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Folks,

Ships Chemical Smoke Munitions, OP 1042, 1944, describes chemical smoke systems for creating smoke screens.

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RESTRICTED
ORDNANCE PAMPHLET NO. 1042
INCLUDING: CHANGE 1
CHANGE 2
OCL AV3-44
OCL A48-44
OTI A3-44
SHIPS CHEMICAL SMOKE MUNITIONS
DESCRIPTION AND INSTRUCTIONS FOR USE
Department of the Navy, Bureau of Ordnance
A BUREAU OF ORDNANCE PUBLICATlON  25 SEPTEMBER 1943



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RESTRICTED

NAVY DEPARTMENT, BUREAU OF ORDNANCE,
WASHINGTON 25, D. C.

OP 1042  CHANGE 1

21 August 1944

1 Page - Page 1

To all holders of Ordnance Pamphlet 1042
insert change; write on cover 'Change 1 entered'
Approved by The Chief of The Bureau of Ordnance
Acting Chief of Bureau

ORDNANCE PAMPHLET 1042
is changed as follows:
SHIPS CHEMICAL SMOKE MUNITIONS

Insert at end of Chapter. V:

SAFETY DISTANCES FOR OPERATION OF SMOKE SCREEN GENERATOR MK 3

The Bureau has conducted a series of tests to determine the distance from depth charges at which the Smoke Screen Generator Mk 3, consisting of one (1) Smoke Screen Rack Mk 1 and four (4) Smoke Pots Mk 3, may be operated with safety.

These tests were made by burning Smoke Pots Mk 3 at varying distances from a Depth Charge Mk 8. At each distance, a series of sixteen (16) pots were burned, four (4) at a time, with as little time as possible lost between burnings. The depth charge was placed with its center line approximately eight inches (8"). above the pots, and a blower was placed in a position to blow the smoke directly over the depth charge to simulate the worst possible conditions. In some of the tests, the depth charge was placed with the booster-detonator end nearest the pots. In others, the longitudinal axis of the depth charge was placed parallel to the Smoke Screen Generator Mk 3. No results were noticed until the depth charge was placed six inches (6") from the burning pots, at which time there was a slight low-order detonation.

From these tests it is believed that the Smoke Generator Mk 3 may be operated with safety at distances beyond two feet (2') from depth charges, but that operation within two feet (2') should be considered dangerous.

DISTRIBUTION

Additional copies of OP 1042 Change 1 may be obtained by submitting requests on NAVORD FORM 1, ORDNANCE PUBLICATIONS AND FORMS REQUISITION, in accordance with the procedure outlined in OCL V15-43 (1st Rev.), or to the nearest Ordnance Publications Distribution Center: Navy Yard, Wash. 25, D.C.; Adak, Alaska; Mare Island, Calif.; Pearl Harbor, T.H.;Espiritu Santo, New Hebrides; Exeter, England; Brisbane, Australia. NAS and Distribution Center mailing addresses should be obtained from the Standard Navy Distribution List, or from the reverse side of NAVORD FORM 1.

Standard Navy Distribution List No. 26
2 copies each unless otherwise noted.

1.
2. c-f, h, k, m, n, q, t, v, w.
3. b, c, e, f, g, i-r, r-1, t-11, nn-yy, aaa, bbb.
3. 5 copies) a, d.
B3. (5 copies) LIONS, CUBS, ACORNS.
4. b, c, e, f, h-n, p-r, nn-rr, tt-yy, aaa, bbb.
4. (5 copies), a, d.
5. b.
6. a.
7. e, j*, s, x.
7. (5 copies) a, b, c, p.
8. a*, h*, n(SPECIAL LISTS N, P, R, S, z).
10. g*, 1, j, t.
10. (25 copies) nn.
11. a (BuShips, CNO, ComdtMarCorps)
12. a, b.
14. a, k-m, q, s.

* Applicable addressees.



1
 
RESTRICTED

NAVY DEPARTMENT, BUREAU OF ORDNANCE,
WASHINGTON 25, D. C.

OP 1042  CHANGE 2

10 November 1944

2 Page - Page 1

To all holders of Ordnance Pamphlet 1042
insert change; write on cover 'Change 2 entered'
Approved by The Chief of The Bureau of Ordnance
Acting Chief of Bureau

ORDNANCE PAMPHLET 1042
is changed as follows:
SHIPS CHEMICAL SMOKE MUNITIONS

1. Paragraph 90(e), page 61, is cancelled and superseded by the following:

90(e). Service use of the Floating Smoke Pot, HC, M4, revealed two serious defects. There is insufficient internal bracing to the pull wire igniter fuze and the solid HC, Smoke mix cake. During the normal handling incident to shipping, the internal support of the pull wire igniter is liable to come loose, and either activate the pull wire or make it prone to activation with any subsequent jolt or drop. It may also so disrupt the fuze that it will not function at all. Lack of support for the smoke mix allows it to break up during any rough handling. This results in a much faster rate of burning of the smoke mix, and shortens the period of smoke emission.

90(f). To eliminate the bad features of the pot M4, a modified pot, the M4A1, was developed in which a bouchon firing device is incorporated, and the safety fuze and fuze support is replaced by a steel pipe containing a powder train which extends from the bouchon fuze adapter to a perforated sheet steel disc holding the smoke mix cake in place. This pot has a disadvantage in that the bouchon extends above the level of the pot and is subject to damage during shipment. It also prevents stacking of the unboxed pots. This pot was produced in very limited quantities as a stop gap while a further modification, the M4A2, was being developed.

90(g). The Floating Smoke Pot M4A2 differs from the M4A1 in that the cover plate has been provided with a circular well in its center 6 inches in diameter and approximately 1.4 inches deep, into which the bouchon fits with no part projecting above the cover. A pull ring is attached to the safety pin of the bouchon by a 6-inch chain to facilitate firing; and the entire well is covered with a chipboard shield which, in turn, is covered by a waterproof adhesive sheet which extends over the emission ports. This pot has similar operational characteristics to the pots M4 and M4A1; namely, a 10-second delay and a burning time of 10 to 15 minutes. It contains 2 pounds of fast-burning HC mix and 25 pounds of a slow-burning mix.

2. Paragraph 92, page 61, is cancelled and superseded by the following:

92(a). Within 24 hours of firing the smoke pots, the vent hole covers must be removed for five minutes and then replaced.

92(b). To fire the pot M4, remove the adhesive tape covering the pull wire, but do not remove the tape covering the vent holes and the fuze support nail. Give the pull wire a sharp pull, and about 10 to 20 seconds later smoke will start. The pressure of the gases is sufficient to blow the tape off the vent holes.

92(c). To fire the pot M4A1, all that is necessary is to pull out the safety pin of the bouchon fuze. The pot M4A2 is fired similarly except that it is necessary to remove the chip-board shield which protects the bouchon.

3. Paragraph 93(b), page 61, is cancelled and superseded by the following:

93(b). On the pot M4, only the fuze pull wire tape should be removed when the pot is being put into operation. This tape should not be removed until immediately prior to firing the pot.

4. Paragraph 94, page 61, is cancelled and superseded by the following:

94(a). The Floating Smoke Pot, HC, M4, must be handled with extreme care during stowage operations and in shipment. Do not roll, skid, drop, or jolt crated or individual pots. Always stow them right side up.

94(b). As with all HC Smoke Pots, they should not be stowed with other ammunition and should never be overstowed with other cargo when large quantities are cargo-loaded below decks. Shipboard allowance should always be stowed topside, convenient for jettisoning and protected from the weather.

94(c). In case a pot catches on fire, fight fire with large quantities of water. Do not use foamite or carbon dioxide extinguishers, or fog nozzles, as they are not effective.

94(d). All ships carrying HC Smoke Pots should have Rescue Breathing apparatus and gas masks. Personnel should not enter or remain in enclosed spaces containing BC Smoke without wearing a gas mask or Rescue Breathing Equipment. If the likelihood of a lack of oxygen



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in the atmosphere exists due to causes other than the burning of the HC Smoke munitions, Rescue Breathing Equipment only shall be worn. In addition, it is recommended that personnel who must remain near an HBC munition generating smoke in the open, wear gas masks.

DISTRIBUTION

Additional copies of OP 1042 Change 2 may be obtained by submitting requests on NAVORD FORM 1, ORDNANCE PUBLICATIONS AND FORMS REQUISITION, to the nearest Ordnance Publications Distribution Center: Navy Yard, Wash. 25, D.C.; Adak, Alaska; Mare Island, Calif.; Pearl Harbor, T.H.;Espiritu Santo, New Hebrides; Exeter, England; Manus Island, Admiralty Islands. Distribution Center mailing addresses should be obtained from the List 10 nn of the Standard Navy Distribution List, or from the reverse side of NAVORD FORM 1.

Standard Navy Distribution List No. 28
2 copies each unless otherwise noted.

1. a-h, i-1;
2. d-f, h, k*, m, m(1), n, q-u, w, x;
3. b, c, e, f, g, i-r, r(1), t-11, nn-yy, aaa-ccc;
3. (5 copies), a, d;
4. b, c, e, f, h-n, p-r, t-11, nn-rr, tt-yy, aaa, bbb;
5. b*;
6. a;
7. e, f,h, i, o, x, z;
7. (5 copies), b, c, d, j, p, s;
8. a*, h*, i, j, n(SPECIAL LISTS G, K, L, N, P, R, S, V, Z), q, v;
8. (10 copies), r;
10. g*, i, j, t;
10. (25 copies), nn;
11. a(Buships, BuAer, BuDocks, CNO, ComdtMarCorps);
12. a, b(Revision 1)
13. a, c-f, aa-ddd, hh;
13. (5 copies), r;
14. a, k;

* Applicable addressees.



1
 
S77
(Re2d)
RESTRICTED
NAVY DEPARTMENT
BUREAU OF ORDNANCE
WASHINGTON, D. C.
NAVORD OCL AV3-44
17 January 1944

BUREAU OF ORDNANCE CIRCULAR LETTER AV3-44

Subject: Chemical Smoke Munitions

Reference:
(a) O.P. 1050
(b) O.P. 1042
(c) NavOrd O.C.L. A38-43

1. The purpose of this letter is to furnish the operating forces immediate information concerning the nomenclature and operating characteristics of chemical smoke munitions as a guide to their practical use. The majority of these munitions are described in references (a) and (b). Reference (b) will not be available for distribution, however, until February, 1944.

2. The smoke producing agents are HC or hexachlorethane type smoke mixture, FS or sulfur trioxide in chlorosulfonic acid, FM or titanium tetrachloride, and WP or white phosphorus. Precautions to take with these mixtures are given in reference (c).

3. The Navy Chemical Smoke Screen Generators.

(a) The Mark 1 Mod 1 (FS) Smoke Screen Generator consists of 4 smoke generator tanks Mark 1 mounted in two tiers. Each tank may be used as a single unit or simultaneously with 1 or more of the other tanks. The FS is ejected by pressure from the ships' high pressure air lines (Max. pressure is 150 lbs/sq.in.). The generator has overall dimensions of 70" long, 32 1/2" wide, 38" high and occupies 16 sq. ft, of deck space. It weighs 3198 lbs. when filled with 2048 lbs. of FS and produces smoke for 6 1/2 to 85 minutes. It is primarily for use on CLs and DDs.

(b) The Mark 2 (FS) Smoke Screen Generator has a single Mark 1 smoke generator tank. The FS is ejected by pressure from a CO2 bottle (max. pressure is 150 lbs/sq.in.). The generator is 68" long, 22" high, and 17" wide, occupying 8 sq. ft. of deck space. It weighs 974 lbs. filled with 512 lbs. of FS and generates smoke for 6 1/2 to 21 minutes. It may be used on escort ships smaller than DDs.

(c) The Mark 3 Smoke Screen Generator consists of 4 HC Smoke Pots Mark 3 and a smoke generator rack Mark 1. It is 48 1/4" long, 17 3/4" wide and 12" high but occupies negligible deck space as the rack is mounted so that it extends over the water abaft the stern. When all the pots are in simultaneous operation, smoke is generated for 5 to 6 minutes. The generator is designed for use on landing and landing support boats where weight and space is at a premium. Total weight is 165 lbs with 128 lbs of HC.

(d) The Mark 4 Smoke Screen Generator (FM) consists of 4 smoke generator tanks Mark 2 mounted in a single unit in two layers. CO2 mixed with the FM in the tank is the smoke ejecting agent. The pressure, therefore, depends on the temperature of the mixture. The generator weighs 2403 lbs. when filled with 1320 lbs. of



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FM and CO2. It is 58.5" long, 40 3/4" high, 36 1/2" wide and occupies 15 sq. ft. of deck space. Smoke can be ejected for 2 1/2 to 100 minutes. The generator is designed for use on CLs and DDs.

(e) The Smoke Screen Generator Mark 5 (FS) is the Mark 2 Smoke Screen Generator modified to be mounted in a depth charge release track.

(f) The Smoke Screen Generator Mark 6 (FM) is a single (Mark 2 Tank) tank unit designed especially for PT boats. It generates smoke for 2 1/2 to 25 minutes. It is 58" long, 17 1/2" high, and 18" wide, occupying 7 1/4 sq. ft. of deck space. It weighs 544 pounds when filled with 330 lbs. of FM and CO2.

4. Smoke Bombs. The Navy is only using two smoke bombs at this time - the 50 lb. Mark 1 Mod 1 floating smoke bomb and the 100 lbs. Mark 3 floating smoke bomb. Both are HC filled. The 50 lb. bomb is 35 1/3" long, 8 7/8" in diameter and weighs 54 lbs. when filled with 28 lbs. of HC. It generates smoke for 3 minutes. The 100 lb. bomb is 48 1/2" long, 10 1/4" in diameter and weighs 102 lbs. when filled with 59 lbs. of HC. It produces smoke for 7 to 8 minutes.

5. Floats

(a) The Mark 1 Smoke Float (HC) weighs 165 lbs. when filled with 90 lbs. of HC. It is 30.7" high by 22.5" in diameter and produces smoke for 18 - 21 minutes. It is designed to be used as a pot mounted on a noninflammable platform on deck or as a float for the protection of convoys against submarines.

(b) The Mark 2 Smoke Float (HC) is nearly identical to the Mark 1 Float. The differences were merely to aid production and do not alter operation characteristics.

(c) The Floating Smoke Pots M-4 and M4A1 are 13" high by 12" in diameter and weigh 35 lbs. when filled with 26 lbs. of HC. They generate smoke for 10 - 15 minutes and are designed for amphibious operations.

6. Smoke Pots or Grenades (non-floating)

(a) The Smoke Pot M-1 is an HC filled smoke pot for escort vessels and miscellaneous uses. It is 9.5" high, 5.2" in diameter and weighs 134 lbs. when filled with 122 lbs. of HC. It generates smoke for 5 - 8 minutes.

(b) The Smoke Pot Mark 3 is an HC filled smoke pot designed for use in the Mark 3 Smoke Screen Generator (paragraph 3-c). It is 9" high, 8.5" in diameter and weighs 34 lbs. when filled with 32 lbs. of HC. It generates smoke for 5 - 6 minutes. The volume of smoke is superior to that of the M-1 pot, since over twice as much HC is burned in approximately the same time interval.

(c) The small Navy Training Candle is a small tobacco can shaped can 2" high, 2" long, and 1" wide filled with HC. It is designed to simulate fires in damage control practices and is the only naval HC smoke pot that produces a small



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enough quantity of smoke to be used safely (personnel need not wear gas masks) in confined spaces such as below decks.

(d) The AN M-8 Smoke Grenade (HC) is 5 3/4" high, 2 5/16" in diameter and weighs 1 3/4 lbs. when filled with 1 lb. of HC. It produces smoke for 2 1/4 to 3 1/4 minutes. While primarily used as a signal, it may be used to generate a small cloud of smoke if no large pot is available.

7. Smoke Projectiles

(a) The Navy Smoke projectiles at this time are limited to 5"/38 caliber WP filled projectiles. These are designed for laying down a surface screen or an antiaircraft cloud in the air. They may also be used as bombardment weapons to start fires in easily inflammable targets and to produce casualties. The projectile is a bursting munition holding 7.2 lbs. of WP. It has an effective range of 8000 yards and produces an initial burst of about 70 yds. in diameter.

(b) While the Navy has only the smoke projectile described above, in combined operations with the Marine Corps or the Army the 4.2" chemical mortars will often be available. This is a rapid firing munition with a range of over 4000 yds. The WP charge in the shell is slightly greater than that of the 5"/58 projectile.

8. Smoke Rockets are a recent development and are available still in very limited quantities.

(a) The 4.5" rocket holds 12 lbs. of FS (WP in the future) and has a range of about 1100 yds.

(b) The 7.2" rocket holds 20 lbs. of FS and has a 3700 yd. range.

9. Aircraft Spray Tanks (FS)

(a) The Mark 5 and Mods Smoke Screen tank (50 gal.) is a monel metal tank 67" long and 19" in diameter. The complete tank weighs 947 lbs. when filled with 727 lbs. of FS. It ejects smoke for a period of about 25 to 80 seconds.

(b) The Mark 6 Smoke Screen tank (50 gal.) (now obsolete) is similar to the Mark 5 tank, but smaller, weighing 593 lbs. when filled with 442 lbs. of FS. It ejects smoke for 15 to 50 seconds.

(c) The Army has the following smoke tanks that may be used by the Navy in emergencies. The M-10 tank weighs 68 lbs. empty and has a 30 gal. capacity. The M-5 tank weighs 175 lbs. empty and has a 70 gal.capacity. Both are gravity flow tanks. Also the Army has the M-20 and M-21 tanks which are identical to the Navy Mark 5 and Mark 6 tanks, respectively, except that they are constructed of mild or copper-bearing steel instead of monel. These tanks can be used only on Army type planes in use by the Navy.

G.F. Hussey, Jr., Rear Admiral, U.S. Navy, Chief of Bureau



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DISTRIBUTION;
Standard Navy Distribution List No. 19
2 copies each unless otherwise noted.

1.a-e,g-n,q-u,w,x,z-ff,ii-uu,ww-zz; 1.(5 copies),o,p,y,gg; 2.a,b,d-p,r-t, v-ee,hh-11; 2.(5 copies),c,u; 3.b,c,e-h,i-r,t-ccc; 3.(5 copies),a,d; B3. (5 copies),LIONS,CUBS,ACORNS; 4.b,c,e,f,h,k-n,p-r,u,w-rr,tt-yy,aaa; 4.(5 copies),a,d,i,j; 5.b(Alusna, London only); 6.a,b,d-w; 6.(4 copies),c; 7. b,g,l,o,p,s,x,z; 7.(5 copies),c-f,h-j,w; 7.(10 copies),a; 8.b,h(NOL and NO. Beach only),i,j(except Panama City & Neah Bay),n(SPECIAL LIST A,B,C,D,E,F, G,H,I,L,N,P,R,S,V,Z,AA,BB),r,v,cc; 8.(10 copies),r; 10.b(except Wright Field), d(except Aircooled Motors, Syracuse, N.Y.),n(Pollack Mfg. Co. only),t,gg; 10.(5 copies),b(Wright Field, Dayton, Ohio only),c(except Dallas, Texas & Pratt & Whitney, Hartford,Conn),nn(Via Airmail); 11.a(BuShips,BuAer,BuDocks,CNO,SecNav, ComdMarCorps); 12.; 13.c-q,s,v-x,z,aa; 13.(5 copies),r; 14.a,b(except Washington),i,k,q,s; 14.(5 copies),g; Naval Unit, Edgewood Arsenal, Md.; Chief of Chemical Warfare Service, U.S.A.; Ammunition Dumps, Navy Nos. 93,101,117, 138,142,147,157,220,65,127,129,143,144,151,152,156,203,714, Annette Island, Cold Bay, Port Althorp, c/o U. S. Fuel Depot, San Diego, c/o U. S. Fuel Depot, San Pedro, Levis, P. Q. Canada; AvSly Annex-Norfolk, Oakland; OCO, War Dept.; CG, AAF(Attn: Air Ordnance Officer, (11 copies); Hdqtrs, Air Service Command, Mntce Div., Patterson Field, Fairfield, Ohio, Desk MQw; Design & Drafting Div., NYd, D.C. (Attn: Comdr, F. B. Schaede); USCG Institute, Groton, Conn; Comdt, NAS, Patuxent, (Attn: Aircraft Armament Unit); OinC, Training Dept., NAS, Quonset Point, R.I; ComAirLant, Ord Field Service Unit, NAS, Norfolk; Naval Aircraft Pool, Navy No. 131; Hdqtrs, ComAirSols, Navy No. 250; (10 copies), OinC, B-3, Navy No. 140.

Additional copies of OCL AV3-44 needed by aircraft activities should be obtained in accordance with the procedure outlined in OCL V15-43. All other activities should address requests for this publication to the nearest BuOrd Publications Distribution Center: Comfit and Supt, NavGun, YYd, Wash., 25,D. C. (Attn: OrdPubSubcen); OinC, OrdPubSubcen, NSD, Pearl; Comfit, NYd, Mare Island, Calif.; (Attn: OrdPubSubcen); ComServFor, SEVENTH FLEET, OrdPubSubcen, %FPO, SanFran



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S70-1(9)
(Mn2e)
RESTRICTED
NAVY DEPARTMENT
BUREAU OF ORDNANCE
WASHINGTON, D. C.
NAVORD OCL A48-44
24 June 1944

BUREAU OF ORDNANCE CIRCULAR LETTER A48-44

Subject: Smoke Floats Mk 2.

Reference:
(a) OP 1042, Ships Chemical Smoke Munitions.
(b) OHI C1-44, Instructions for Handling and Firing the Smoke Float Mark 2.

1. There have been several instances of spontaneous ignition in early lots of subject floats. The cause has been attributed to moisture getting into the smoke-mix can and reacting with the HC mix, igniting It after a short delay. The points of entry of this moisture are believed to be at the seal between the igniter and the pyrotechnic container, where the watertight integrity has been broken by rough handling, or by seepage along the threads of the nut locking the igniter to the container.

2. In order to insure serviceability of floats and to protect against premature ignition, all Smoke Floats Mark 2 of lots 1 to 85 inclusive manufactured by Aerial Products Inc. at Merrick, Long Island, under contract NOrd 3475 that are in storage in shipping boxes, should be reconditioned as follows:

(a) Open each wooden packing box, loosen toggle-bolt wing nuts, and remove clamping yoke.

(b) See that the igniter fitting lock nut is secure. If the lock nut is loose to the hand, tighten it with a wrench. If this can not be tightened satisfactorily, the pyrotechnic can should be destroyed.

(c) See that the igniter itself is secure. If the igniter can be unscrewed by hand, the igniter should be removed, being careful not to lose the lead washer. If there is any visible moisture in the igniter can or on the igniter, the pyrotechnic can and igniter should be destroyed. If



2
 
no moisture is found, reassemble igniter end tighten with a wrench. If the igniter is secure to the hand, it can be assumed that no moisture was able to get in and that assembly is satisfactory.

(d) Remove the knurled cap protecting the pull-wire, and see that the pull-wire is dry. Replace the cap.

(e) Drive three wooden wedges between the pyrotechnic can and flotation chamber on the upper edge approximately 120 degrees apart. This will prevent chafing between the float and the pyrotechnic can. Wedges shall not interfere with the smoke ports, and care should be taken not to damage a smoke port.

(f) Replace the clamping yoke and secure the toggle-bolt wing nuts from backing off by installing lock washers under the wing nuts or by wiring on.

(g) See that. each float is located upright in the packing box, and fasten in the braces securely. Nail down the cover of the box.

(h) Paint "This Side Up" and "Handle With Care."

Any crated floats of these lots marked "This Side Up" have been reconditioned and need no further overhauling.

3. Floats aboard ship should be inspected periodically to insure that the locking nut of the igniter assembly and the igniter itself are both sealed tightly. If they have come loose, they should be inspected as outlined in paragraphs 2 (b) and (c) above.

4. In addition to the above, all floats on Contract NOrd 3475 in lots 1 to 85 inclusive were made with steel pull-wires. Moisture may work its way under the cap and so corrode this wire that it will break off when activated.



3
 
Frequent inspection of these steel pull-wires is necessary on floats installed aboard ship. Coating the wire with a heavy grease will help to prevent corrosion. Floats with corroded wires should be destroyed, unless spare igniters are available.

5. All floats that are damaged so that their watertight integrity is in question, or have been condemned in the overhaul inspection outlined above, should be destroyed by removing the pyrotechnic can and either dumping it overboard in water 50 fathoms deep and at least 10 miles offshore, or by burning in an isolated area where fire cannot spread and the large volume of smoke produced will create no hazard. The flotation chambers should be dumped overboard or salvaged for scrap metal if convenient.

6. Smoke floats should be handled with care during shipment. They should not be dropped, skidded, or rolled, and should always be kept right side up. As with all smoke-producing ammunition, they should be deck-stowed if possible; but when large quantities are being shipped as cargo, they are suitable for stowage in any tight cargo hold provided they are not overstowed with other cargo and every two tiers are floored off.

7. If a smoke float ignites accidentally, the principal danger is from spreading of the fire to the wooden crates of adjacent floats and subsequent ignition of these floats. Water in lame volume should be used in fighting HC smoke-mix fires. Foamite and carbon dioxide extinguishers or fog nozzles are less effective, as HC smoke-mix does not require atmospheric oxygen for its reaction. Large volumes of water will extinguish a burning smoke float.

8. HC smoke is toxic in heavy concentrations, and all personnel exposed to such concentrations should wear rescue-breathing apparatus or gas masks (provided there is sufficient oxygen).

9. Smoke floats may be stowed in the open ashore when necessary provided dunnage and tarpaulins are used.

G.F. Hussey, JR Rear Admiral, U.S. Navy, Chief of Bureau



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Requests for additional copies of OCL A48-44 should be directed to the nearest Distribution Center: Navy Yard, Washington, D.C.; Mare California; Kodiak, Alaska; Pearl Harbor, Hawaii; Epiritu Santo, New Hebrides; Exeter, England; Brisbane, Australia. Distribution Center mailing addresses should be obtained from list 10 nn on the Standard Navy Distribution List.

DISTRIBUTION

Standard Distribution List No, 24
2 copies ee c unless otherwise noted,

1,a-1; 1,(5 copies), g; 2, c-f, h,i, k, m, n, q-t,v,w; 3. a-rl, t-11, nn-ccc;B3.(5 copies), LIONS, CUBS, ACORNS; 4,b,e,f,n,qq,rr; 5.b; 6.a-p; 7.e-h,s; 7.(5 copies), a-d,p,x; 8.a,h,k,n(SPECIAL LIST G,K,N,P, R,S,V,Z,AA),u; 8.(5 copies),i.j,q,r; 10.g*t; 10.(25 copies),s,nn; 11.a(BuShips, BuDocks, ComdtMarCorps); 12,a,b(Revision 1); 14.a-e,k,g.

*Applicable Addressees



1
 
RESTRICTED
NAVY DEPARTMENT, BUREAU OF ORDNANCE,
WASHINGTON 25, D. C.
NAVORD OTI A3-44

Date  16 May 1944

3 Page - Page 1

Approved by The Chief of The Bureau of Ordnance
ORDNANCE TECHNICAL INSTRUCTIONS
AMMUNITION AND PYROTECHNICS
Acting Chief of Bureau

CONTENTS

Paragraph Page
1 References 1
2 Purpose 1
3 Description 1
4 Installation 1
5 Operation 2
6 Maintenance 2
7 Special Precautions 2
4".5 ROCKET (WP SMOKE)
(ASSEMBLY NO. 4.5SMO13)

ILLUSTRATIONS

Page
BuOrd Drawing Number 394439 3

1. REFERENCES

(a) Ordnance Pamphlet 1017.
(b) Ordnance Pamphlet 1042.
(c) Ordnance Pamphlet 1003.
(d) Bureau of Ordnance Manual.

2. PURPOSE

This OTI is issued to provide instructions for the assembly of the 4".5 Rocket (WP Smoke) (Assembly No. 4.5SM013) consisting of the 4".5 Rocket Body Mark 7 (WP Smoke), 2"25 Rocket Motor Mark 9, Nose Fuze Mark 137 Mod. 1, and separate tetryl burster. This fuze and burster assembly for the 4".5 Rocket Body Mark 7 (WP Smoke) is only temporary and will be replaced by the Fuze Mark 154, which will be covered in a later OTI.

3. DESCRIPTION

The complete body assembly of the 4".5 Rocket Body Mark 7 (WP Smoke) (see fig. 1) includes a tetryl-loaded metal burster tube installed in a steel well in the rocket body and a Nose Fuze Mark 137 Mod. 1. The WP-loaded rocket body, the 2".25 Rocket Motor, the tetryl burster, and the Fuze Mark 137 Mod: 1 are each shipped in a separate container and must be assembled prior to firing the rocket. The WP-loaded rocket body is not shipped with the tetryl burster installed, because of the hazard from leakage of WP, which might cause the burster to detonate. When the 4".5 WP Rocket strikes the target, the fuze detonates the tetryl burster, which shatters the rocket body and scatters pieces of burning white phosphorus over a circular area approximately fifty (50) yards in diameter. Failure to install the tetryl burster in the rocket body will result in the production of little or no smoke when the rocket strikes the target.

4. INSTALLATION

A. General. 2".25 Rocket Motors Mark 9, Nose Fuzes Mark 137 Mod. 1, and tetryl bursters are to be stowed separately in accordance with references (c) and (d). 4".5 Rocket Bodies (WP Smoke) are to be stowed separately from the other components in accordance with paragraph 6 below. The tetryl burster should be installed in the 4".5 Rocket Body Mark 7 (WP Smoke) at the time the rocket motor is assembled to the body. Because of the increased hazard in stowing WP smoke-loaded bodies with bursters installed, the burster should not be placed in the body at an earlier time than is necessary to provide ready availability of the ammunition for use.

B. Preparation of Body. Remove the nose shipping plug from the body. Beneath this plug are: (1) A cardboard tube which acts as a spacer; (2) a small threaded steel collar; and (3) a small cork washer. Remove all of these pieces from the body and carefully retain them.

C. Burster. The tetryl burster is 14" long by 5/8" in diameter, and contains approximately 1/8 of a pound of tetryl. The bursters are shipped in wooden boxes marked: "Burster Tube for 4".2 Chemical Mortar Shell." Obtain a burster from the box and remove and discard the protecting waterproof tape and shellacked paper disc on the threaded end of the burster. Assemble the threaded steel collar mentioned in paragraph B. to the threaded end of the tetryl burster. Care must be taken that no loose tetryl at the open end of the tube becomes squeezed between the threaded sections of the two pieces during union, or between the top surface of the collar and the top surface of the tube. Insert the cork washer mentioned in paragraph B. above into the fuze seat liner and position it concentric with the mouth of the burster well. Carefully insert the burster into the rocket body. The collar on the burster should rest firmly on the cork washer, and the washer in turn should rest firmly against the mouth of the burster well.

D. Fuze. When it is intended to have the round ready to fire, a Nose Fuze Mark 137 Mod. 1 should be screwed into the nose of the rocket in the usual manner (see reference (a)).



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E. Disassembly. If for any reason, it is desired to disassemble a fuzed rocket, the fuze. Should be unscrewed first, the burster carefully removed and restowed with the steel collar attached, the cork washer and the cardboard spacer tube should be placed in the fuze seat liner, and the nose shipping plug should be installed. After this operation, the motor should be unscrewed from the rocket body, and all components of the rocket returned to their stowages.

5. OPERATION

For operation of the 4".5 Rocket (WP Smoke) see reference (c).

6. MAINTENANCE

4".5 Rocket Bodies, WP Smoke-loaded, should be stowed in a cool place base down, if practicable, so that in case the temperature in stowage temporarily exceeds 120° F. and the WP melts, solidification of the WP on cooling will not disturb the center of gravity of the body. Stowage of WP-loaded rocket bodies aboard ship should be topside and readily jettisonable if practicable. Stowage lockers provided topside should be equipped with sprinkling systems. If such stowage is not practicable, WP-loaded rocket bodies may be stowed below decks in space which can be completely flooded, which contains no other ammunition of any kind, and in which the temperature does not exceed 120° F.

7. SPECIAL PRECAUTIONS

Reference (b) gives the precautions to be taken with WP smoke munitions. In general WP ignites spontaneously on contact with the air; and because of this hazard, WP-loaded munitions should be stowed separately from other types of ammunition and from pyrotechnics. The WP-loaded rocket bodies, the Fuzes Mark 137 Mod. 1, and the tetryl bursters should be handled carefully at all times.

DISTRIBUTION

Requests for additional copies of OTI A3-44 should be directed to the nearest BuOrd Publications Distribution Center: Navy Yard, Washington, D.C.; Mare Island, California; Adak, Alaska; Pearl Harbor, T.H.; Espiritu Santo, New Hebrides; Exeter, England; ComServFor 7th FLEET. Distribution Center mailing addresses should be obtained list 10 nn on the Standard Navy Distribution List.

Standard Navy Distribution List No. 23
2 copies each unless otherwise noted.

1. a, g, h, k, l.
2. k, m, r, t.
3. b, f, h, t-v, rr.
4. b, f, h, t-v, rr(APA's only).
5. b.
7. e-h, i, k.
7. (5 copies) b, c, d(Key West, Norfolk, Quonset and Patuxent only), j,p,s.
7. (10 copies) a.
8. h-k, n(SPECIAL LISTS K, V, AA, BE).
10. qq.
10. (25 copies) nn.
11. a(ComdtMarCorps).
12. a, b(ReVision 1); d.
13. d, e, f, x, sp, hh.
14. s, q.



3
 
4.50 IN. ROCKET BODY MARK 7
BURSTER TUBE ASSEMBLY
AND DETAILS
394439


RESTRICTED ORDNANCE PAMPHLET NO. 1042
SHIPS
CHEMICAL SMOKE MUNITIONS
DESCRIPTION AND INSTRUCTIONS FOR USE
Department of the Navy Bureau of Ordnance


4
 

NAVY DEPARTMENT
BUREAU OF ORDNANCE
WASHINGTON. D. C.

RESTRICTED 25 SEPTEMBER 1943

ORDNANCE PAMPHLET No. 1042.
SHIPS CHEMICAL SMOKE MUNITIONS

1. The purpose of this publication is to furnish cognizant personnel with instructions for the operation, stowage, and handling of chemical munitions used by the Navy to generate smoke screens from surface vessels. Filling instructions are also included for those munitions that will not be procured already filled.

2. This publication should be used as a hand book covering stowage, installation and operation of ships chemical smoke munitions.

3. The following publications are superseded by this publication. They should be destroyed:

Ordnance Pamphlet 734, Smoke Screen Generator Mark 1.
Ordnance Circular Letter A-30-42, Smoke Float Mark 1.
Ordnance Circular Letter A-17-42, WP Smoke Projectiles 5"/38.
Ordnance Circular Letter A-38-43, Precautions to Take with Smoke Munitions.

4. The following publications contain information concerning the subject or related munitions:

Army Technical Manual 3-250, Stowage and Shipment of Dangerous Chemicals.
Ordnance Pamphlet 725, Ships Pyrotechnics.
Ordnance Pamphlet 723, Aircraft Smoke Screen Equipment.
Army Technical Manual 3-300, Irritant Candles, Tear Pots, Smoke Pots, etc.
Army Training Circular 49.
Ordnance Circular Letter A-90-43, Bulk Stowage of FS.

5. This publication is RESTRICTED and will be handled in accordance with Article 76, United States Navy Regulations, 1920

W.H.P. Blandy
Rear Admiral, U.S. Navy
Chief of the Bureau of Ordnance
W.H.P. Blandy
Rear Admiral, U.S. Navy
Chief of the Bureau of Ordnance


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CONTENTS OP 1042
CHAPTER 1 Page
Introduction 7
Purpose 7
Scope 7
CHAPTER 2
Agents 9
FS 9
FM 10
HC 11
WIP 11
CHAPTER 3
FS Generators 15
General 15
Smoke Screen Generator Mark 1 and Mods 15
Smoke Screen Generator Mark 2 23
Smoke Screen Generator Mark 5 26
CHAPTER 4
FM Generators 37
General 37
Smoke Screen Generator Mark 6 37
Smoke, Screen Generator Mark 4 41
 
CHAPTER 5 Page
HC Smoke Screen Generator Mark 3 49
CHAPTER 6
HC Smoke Floats 57
General 57
Smoke Floats Marks 1 and 2 57
Floating Smoke Pots M4 and M-4A1 59
CHAPTER 7
Smoke Pots, Candles, and Grenades 65
General 65
HC Smoke Pot, Mark 3 65
The Smoke Pot M-1 65
Navy HC Training Candle 66
HC Smoke Grenade AN-M8 68
CHAPTER 8
White Phosphorus Projectiles 69
 

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FM SMOKE
(From Smoke Screen Generator Mark 6)
FM SMOKE
(From Smoke Screen Generator Mark 6)
 

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INTRODUCTION OP 1042

CHAPTER 1

 

PURPOSE

1. The purpose of this pamphlet is to furnish qualified personnel with a description of ships' chemical smoke munitions now in use. The term, "ships chemical smoke munitions," is applied to all chemical smoke munitions other than aircraft smoke bombs and spray tanks that are used to generate blanketing or screening clouds as distinct from oil smoke generators and those chemical smoke munitions designed primarily for signaling devices.

2. This pamphlet also includes instructions for the operation, stowage, and handling of chemical munitions used by the Navy to generate smoke screen from surface vessels. Filling instructions also are included for those munitions that will not be procured already filled.

  SCOPE

3. The following smoke producing agents and munitions are covered by this pamphlet:

(a) AGENTS:

FS.
FM.
HC.
WP.

(b) MUNITIONS:

FS Generators; Mark 1, Mark 2, and Mark 5.
FM Generators; Marks 4 and 6.
HC Generator; Mark 3.
HC Smoke Floats; Smoke Floats Marks 1 and 2, Floating Pots M-4 and M-4A1.
HC Smoke Pots (Mark 3 and M-1), Candles (Navy Small Training), and Grenades (M-8).
WP Smoke Projectile, 5 in. 38 caliber.

 

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This page is blank.
 

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AGENTS OP 1042

CHAPTER 2

 

FS

4. GENERAL

FS generates a dense, white, corrosive smoke. It is primarily used for aircraft spray tanks and the Marks 1, 2, and 5 Smoke Screen Generators for use on surface vessels. It may also be used as a filler for new munitions now being developed.

5. COMPOSITION

FS is a solution of sulfur trioxide in the liquid chlorosulfonic acid. It is a very corrosive, heavy, fuming liquid, and weighs about 16 pounds per gallon. In contact with air it reacts with the moisture present to form a mixture of sulfuric and hydrochloric acid mist. Not only the smoke mixture, but also the smoke is corrosive.

6. STOWAGE

FS is obtained and stowed in 55 gallon steel drums. It is stable inside these drums where it is concentrated, but fumes leaking out past the bung hole plugs will react with moisture in the air to form a corrosive mist that will corrode the outside of the drums. The stowage of FS drums resolves, therefore, to prevention of corrosion to the outer surfaces of the drums.

(a) The drums should be painted on the outside with an acid- and weather-proof paint, such as the Navy Projectile Cavity paint (O.S. No. 1356).

(b) They should be stowed in well ventilated magazines ashore (stowage in the open is permissible in the continental United States if the outer surfaces are kept well painted). They should be kept on racks at least four to six inches above the ground

  or floor, as FS vapors are heavy and hug the ground.

(c) Aboard ship they should be stowed topside only, but protected from the weather, especially the sun, and from salt water spray.

(d) The drums must be constantly inspected for signs of corrosion, leakage, and paint deterioration.

(e) The drums should not be vented, despite contrary instructions in O.P. 723, O.P. 725, and O.P. 734, except when the drums are actually bulging due to the pressure, or when they are to be opened. When venting is thus necessary, the drums to be vented should be removed from the place of stowage to prevent contamination of the remaining drums. When it is desired to open, FS drums should be sufficiently removed from the place of stowage so that the corrosive vapors released when the plug is removed will not be able to contaminate the other drums. When a drum begins to leak badly, the FS should be transferred to an empty non-leaking drum. If no suitable empty drums are available, the leaking drum should be disposed of in order to avoid subjecting the other drums to the corrosive atmosphere created by the leaking. Disposal of leaking drums is accomplished either by dumping them in deep water at sea or, if that is not practicable, dumping them into a deep hole in an isolated location down wind from any stowage place, magazine, or inhabited locale and burying them.

7. DECONTAMINATION

Due to the strongly corrosive properties of FS and its smoke, care mould be taken to prevent FS fumes or smoke from

 

10
 
contacting any machinery, aircraft, or delicate equipment that may be near. FS is spilled, it must be destroyed by repeated drowning with water, taking care to avoid injury due to droplets that are likely be scattered by the violent reaction of FS with water. In this respect, a small mount of water should never be allowed to contact a large amount of FS mixture. If any liquid FS should come in contact with any part of the body, it should be immediately wiped off and the body washed with an abundance of water, then rewashed with a weak solution of bicarbonate of soda, or ammonia in water. Contaminated clothing should be immediately removed before washing with water, or serious burns are likely to result.

8. HANDLING

All personnel handling FS or FS munitions must observe the following precautions:

(a) Personnel handling FS drums or munitions should wear acid-proof gloves and boots.

(b) Personnel handling FS during filling operations, or at other times when this agent could splash onto them, should wear acid-proof aprons or clothing, acid-proof gloves, boots, and goggles.

(c) It is preferable for personnel operating in an FS smoke cloud to wear gas masks if possible. Gas masks should always be worn when the cloud is in a confined space where high concentrations of FS smoke exist.

FM

9. GENERAL

FM reacts with the moisture in the air to form a dense, white, persistent smoke cloud. It is used in the Mark 6 generator on P.T. boats, and may also be used on larger craft in the Mark 4 generator. The Mark 4

  generator contains four tanks of the one type used in the single tank Mark 6 generator.

10. COMPOSITION

FM is a compound, titanium tetrachloride. It is used with carbon dioxide as the pressure producing agent, and sometimes with the addition of a small percentage of other chemicals. With or without the additional chemicals, the stowage. handling. and decontamination instructions are the same as for the FS. The smoke mixture is a corrosive colorless to yellow liquid that weighs 14 pounds to the gallon. It reacts vigorously with the moisture in the air to form a combination smoke (finely divided titanium hydrate particles) and mist (hydrochloric acid vapor). Due to the hydrochloric acid, the liquid is highly corrosive, but the smoke, while acrid, is not sufficiently irritating in field concentrations to cause coughing or other physiological effects to the respiratory system.

11. STOWAGE

FM is obtained and stowed in 55-gallon drums, in which it is stable. Stowage instructions are the same as for the FS (paragraph 6), but the corrosion problem on the exterior of the tanks is much less severe because FM is not nearly so volatile as FS.

12. DECONTAMINATION

FM is strongly acidic, though not quite so corrosive as FS. The decontamination instructions for the two mixtures are the same, and may be found in paragraph 7.

13. HANDLING

All personnel handling FM should wear acid-proof clothing, goggles, rubber gloves, and boots, As FM smoke in the open is not very corrosive, a gas mask need not be worn unless the screen is being generated in enclosed

 

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spaces where a high concentration is possible.

HC

14. GENERAL

HC smoke mixture is a solid that reacts to form a very dense, persistent, white to gray smoke cloud. It is used in smoke candles, pots, floats, and grenades.

15. COMPOSITION

There are several possible HC mixtures, all containing hexachlorethane and a metal or metallic oxide or both. The most common mixtures contain hexachlorethane, zinc, and zinc oxide. The relative amounts of these chemicals may vary. Various amounts of other chemicals may be added to alter the burning characteristics of the smoke mixture. Each smoke pot must also have a starting mixture to initiate the reaction of the HC mixture. Once reaction has commenced the temperature rises quickly to above 1000°C and the reaction is self-supporting. When the chemicals in the mixture react, a smoke cloud of metallic chloride (zinc chloride with the Navy HC munitions) and carbon is generated. It should be noted that the heat necessary to start this reaction (usually obtained from the starter mixture) can be obtained by the reaction of water on the mixture. Therefore, spontaneous combustion is possible if moisture is allowed to contact the HC smoke mixture.

16. STOWAGE

HC smoke mixture is obtained already loaded in munitions. These munitions must be stowed by themselves in fireproof magazines away from other munitions. Aboard ship they should always be stowed in topside stowage convenient for jettisoning. They should be protected from the weather,

  but never stowed below deck. In the event of a fire, water should never be used to quench the flames. Personnel fighting the fire should wear masks and use chemical extinguishers.

17. DECONTAMINATION

As HC is a solid and already loaded in munitions, the necessity for decontamination is unlikely to occur. If a munition should break open and spill out some of its contents, it and the spilled HC mixture should immediately be moved to some place where the fire risk is negligible.

18. HANDLING

Care should be taken to handle HC munitions carefully so as not to damage them and destroy their watertight integrity. HC smoke is harmless in concentrations encountered in the field, but becomes somewhat toxic if concentrated. Gas masks are not necessary in the field, therefore, but should be worn if the smoke is generated in enclosed spaces where higher concentrations are possible.

WP

19. GENERAL

WP produces a dense white smoke that tends to pillar somewhat. It is also a moderate incendiary agent. It is used in Naval 5"/38 caliber projectiles and in several Army munitions that may possibly be acquired for Naval use in the future.

20. COMPOSITION

WP is the "white" form of the element phosphorus. L. is a yellow solid at ordinary temperatures. It reacts with the oxygen in air to form a dense white cloud of phosphorus pentoxide. This reaction occurs spontaneously when the two elements come in contact.

 

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21. STOWAGE

Since the canisters of WP are tested at high pressure and are contained within the sealed projectile case, stowage of 5"/38 caliber WP projectiles offers no great hazard. However, since any leakage or malfunctioning in stowage would result in generation of quantities of acrid smoke and fires which are difficult to permanently extinguish, the projectiles should be stowed, protected from rain, spray, and direct sunlight, topside where jettisoning is readily possible. Ashore, the projectiles should be stowed in fireproof magazines away from all other types of munitions.

22. DECONTAMINATION

WP fires are easily extinguished permanently with a 5 per cent copper sulfate solution. If this solution is not available, water or wet sand may be used to temporarily extinguish the fire. Fires thus extinguished will re-ignite when the phosphorus has dried out, however. Therefore, they must be kept wet until all the white phosphorus has been removed. WP in contact with the skin will cause severe and lingering burns. Places of contact should be immediately washed and kept wet until the phosphorus has been

  removed. Washing the affected area with soda solution, followed with a 5 per cent copper sulfate solution, is very effective, but greasy ointments should never be used as such ointments merely spread the contamination.

23. HANDLING

As WP munitions ignite spontaneously in contact with air they should not be handled roughly lest their air-tight integrity be destroyed. If a fire does occur, personnel should wear gloves and keep both the gloves and their shoes wet. WP smoke is poisonous on prolonged and repeated inhalation, but is not likely to be harmful in the concentrations found in smoke screens in the open. Gas masks afford complete protection from concentrated WP smoke, but they tend to become clogged, and therefore they should not be worn except where serious exposure in enclosed spaces is involved.

 

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This page is blank.
 

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Figure 1-Mark 1 Mod 1-Smoke Screen Generator
Figure 1-Mark 1 Mod 1-Smoke Screen Generator

 

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FS GENERATORS OP 1042

CHAPTER 3

24. There are three Navy generators designed for generation of FS smoke screens from surface vessels: The Smoke Screen Generators Mark 1 and Modifications, Mark 2, and Mark 5. The Mark 1 generator, as well as the Modifications, is designed for use on destroyers or larger vessels. The Mark 2 and Mark 5 generators are designed for use on smaller vessels. These generators are similar in that the same generator tank is the basic unit of each. The Mark 1 generator obtains the pressure necessary to disperse the FS from the ship's high pressure air line, while CO2 bottles are the pressure source for the other two generators.

MARK 1 SMOKE SCREEN GENERATOR (AND MODIFICATIONS)
 

25. The Mark 1 Smoke Screen Generator and Modifications are composed of four 35-gallon Mark 1 smoke screen tanks, which are mounted as a single unit, as shown in Figure 1. Each tank has its own pressure line, exhaust tube, and nozzles. The complete unit of four tanks can be immediately jettisoned, either locally by pulling the manual   emergency release lever, or remotely by a quick operating air valve. The tanks are designed for operation at pressures ranging up to 150 pounds per square inch. The same instructions are applicable to both the Mark 1 and the Mark 1 Modification 1 generators, as the modifications are all of a minor nature.
 

16
 

Figure 2-Arrangement of Air Connections
Figure 2-Arrangement of Air Connections

26. The generator tanks are fabricated from welded sheet monel metal. Within each tank are baffle plates to add strength and minimize surging, and a discharge tube, the purpose of which is to empty the tank as completely as possible by taking the liquid   from the low end. On the outside of each tank are two reinforcing bands, which locate and restrain the tank in its mounting; a filling fitting; a flange for smoke exhaust line connection; and a pipe threaded air inlet tube.
 

17
 

Figure 3-Details of Tank and Saddles
Figure 3-Details of Tank and Saddles

27. The Mark 1 smoke screen tanks are mounted in saddles, the lower set of two being welded to the emergency release carrier, while the upper two rest on the lower two tanks. The tank reinforcing bands serve to properly position the upper two saddles. The tanks and upper saddles are secured to the release carrier by tank anchoring slings. The clevis bolts of these slings extend through the cable anchor brackets, the slings being secured and tightened in place by common nuts which, in turn, are secured by check nuts. Spherical washers are provided so that the clevis bolt nuts will not bear directly against the cable and anchor brackets.

28. The emergency release carrier is, in effect, a skid upon which are mounted the generator tanks. It also mounts all piping necessary to conduct air from a single

  connection (which is fixed to the ship's structure) to each tank, and to the piping and nozzles by which the smoke mixture is discharged from the individual tanks. The carrier is restrained vertically by four keys, one adjacent to each corner, which engage suitable parts of the carrier rack. The carrier is normally held in place on the carrier rack by means of a latch bracket secured to the inboard end of the emergency release carrier. This bracket is fitted with a toggle pin which restrains the latch, and this toggle pin must be removed from the bracket before the carrier can be jettisoned.

29. The carrier rack is the frame in which the emergency release carrier is normally mounted. It slants outboard at an angle of 8 degrees to permit jettisoning the generator by gravity.

 

18
 

Figure 4-Release Mechanism
Figure 4-Release Mechanism

30. The release mechanism is mounted on the inboard end of the carrier rack, as shown in Figure 4. It permits the generator to be jettisoned in case of an emergency. Jettisoning may be accomplished either by manual operation, by means of the lever, or by air pressure applied, by operation of a remote valve, to the release air cylinder which is mounted beneath the carrier rack. In either case, it is necessary, first, to remove the toggle pin which normally restrains the latch from opening. As the carrier starts to roll overboard, the emergency   air release coupling lever is freed by the clevis in the carrier, which had previously retained the air coupling cap in place, and the carrier is thereby freed from the ship's air line.

31. Generator air piping, which starts at the permanent supply line and terminates in the air coupling body at the inboard end of the carrier rack, consists of an air coupling cap, a section of flexible hose, and a piping manifold arranged so that the flexible hose may be connected at either side,

 

19
 

Figure 5-Nozzle and Details
Figure 5-Nozzle and Details

and containing two double branch laterals providing four connections from which connecting pipes run to each individual tank. A three-eighths inch stop valve, to select the particular tank or tanks for discharge, and a spring loaded ball check valve, to check the air line against the smoke mixture, are provided in each line from manifold to tank.

32. Generator smoke lines, which are individual lines, each containing a 1.0 inch stop valve, run from each tank to one of four spray nozzles, these spray nozzles

  being mounted at the outboard end of the emergency release carrier.

33. The spray nozzles, shown in Figure 5, are intended to emit the smoke mixture in finely divided form, the resulting spray to form a comparatively wide cone. Nozzles are made adjustable in order to obtain the optimum spray, but the adjustment, once determined, is not intended to be altered in service except to re-establish the original setting. Nozzles should in no case be adjusted so they will permit smoke mixture to fall upon any part of the ship's structure.

 

20
 

Figure 6-Arrangement of Tank Filling Equipment
Figure 6-Arrangement of Tank Filling Equipment

 

21
 
34. Filling caps are provided for each tank. They are intended for use only when tanks are to be filled with smoke mixture, or when, having been discharged, tanks are to be flushed with water. Under normal operating conditions, a filling cap should never be opened unless the tank is known to have been completely discharged, and then only with the precautions described under paragraph 43 (page 28).

35. The mounting of a generator, after original installation, should proceed as follows: The emergency release carrier, with the air connection assembly in place, is to rest upon the rollers which are mounted in the carrier rack, the four keys of the release carrier being properly engaged with their mating parts of the carrier rack, the carrier latching hook being engaged in the carrier latching eye and secured therein by the toggle pin. The four discharge tubes, which pass through holes in the lower cradles, may be loosely in place or may be assembled later. Before proceeding further, the proper lubrication of all rollers and other operating parts should be checked. Two tanks are now placed upon the rollers of the cradles which are part of the release carrier, the rollers being at the centers of the tank reinforcing bands, and the tanks are rotated upon the rollers until the rollers engage the machined recesses in the bands. The upper cradles are now placed upon the two lower tanks, rollers up, and fitting over the raised portions of the reinforcing bands of the lower tanks, and the upper tanks are placed therein, the bands

  of the upper tanks engaging rollers as in the case of the lower tanks. The tank anchoring slings are now checked for proper protection against corrosion, and are installed so that the cables straddle the reinforcing bands of the upper tanks, precautions being taken to insure that the minimum clearances at the ends of the sling devises are maintained. The slings should be so adjusted that no part extends below a line 7.375 inches above the bottom of the carrier rack. If the threaded stem of the clevis extends below that line the excess should be sawn off. Make up the air and smoke discharge pipe connections. If necessary to make up any pipe joints, use soft deflocculated graphite lubricating grease (Standard Stock Catalog No. 14-G-950) as thread lubricant. With all air and smoke valves at the tanks tightly closed, drain water under air pressure from the separation in the air line to the generator tanks, and test the remote quick-operating jettisoning valves for leakage by means of the bleeder valve in the line to the air release cylinder. To dismount a generator, the reverse order of the foregoing procedure will apply. On account of the slope of the carrier rack, it may be considered preferable to build up a generator upon its release carrier while the carrier lies flat on a deck or other approximately horizontal surface, and then to transfer the entire assembly to its place in the carrier rack.
 

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23
 

Figure 7-Mark 2 Smoke Screen Generator
Figure 7-Mark 2 Smoke Screen Generator

MARK 2 SMOKE SCREEN GENERATOR

36. The Mark 2 Smoke Screen Generator is a single tank version of the Mark. 1 generator, except that it utilizes a CO;, bottle instead of the ship's air line to furnish pressure.

37. The Mark 2 generator is mounted in an emergency release carrier in a carrier

  rack similar to those used by the Mark 1 generator, but designed for a single tank. The tank is the Mark 1 smoke screen tank. It is secured to the emergency release carrier in the same manner as the lower tanks in the Mark 1 generator. Jettisoning is accomplished by means of the release lever in
 

24
 

Figure 8-Smoke from Mark 2 Smoke Screen Generator
Figure 8-Smoke from Mark 2 Smoke Screen Generator

the same way as with the Mark 1 generator, except that it can only be done locally as there is no remote jettisoning valve.

38. The CO2 is contained in a cylinder with a capacity of 15 pounds of CO2 Appropriate piping conducts gas from the CO2 equipment through the emergency release slip

  joint attached to the carrier rack and to the tank. A gas control valve, a regulator, and a pressure gage are mounted on the CO2 line.

39. A gas inlet valve and a smoke discharge valve are attached to the tank. The smoke is discharged through a double nozzle. As with the Mark 1 generator, the smoke

 

25
 

Figure 9-Mark 2 Smoke Screen Generator Mounted for Use
Figure 9-Mark 2 Smoke Screen Generator Mounted for Use

 

26
 

Figure 10 Mark 5 Smoke Screen Generator
Figure 10 Mark 5 Smoke Screen Generator

screen is controlled by adjusting the rate of discharge by altering the pressure from the CO2 bottle.

MARK 5 SMOKE SCREEN GENERATOR 40.

The Smoke Screen Generator Mark

  5, as shown in Figure 10 above, is practically identical to the smoke screen generator Mark 2, the only exception being that it is designed to be mounted in a depth charge release track instead of in the emergency release carrier and carrier rack.
 

27
 
FILLING INSTRUCTIONS

The filling of smoke screen generators Marks 1, 2, and 5, will take place aboard tenders or ashore. The object is to transfer 32 gallons of smoke mixture from the 55 gallon bulk stowage drum to the generator tank without spillage, and with as little exposure to the air as possible. As each tank is filled separately, these filling instructions are equally applicable to all the present FS generators, Mark 1, Mark 2, and Mark 5. Navy Filling Equipment Mark 1 Modification 2 is used.

42. RECOMMENDED PROCEDURE

The recommended procedure for filling the Marks 1, 2, and 5 smoke screen generators is as follows:

(a) Secure the drum, on deck, or on a platform, with the two-inch bung up. Secure the tank alongside of the drum, filling end up.

(b) Remove the tank filling cap and install the filling gage, first making sure that the filling gage float is free and will register when the tank is filled. Keep the float stem oiled lightly where it protrudes through the filling gage retaining nut.

(c) Make sure that the air and discharge stop valves on the tank, and the plug cocks in the filling and vent hoses are closed.

(d) Make sure that the gasket of the filling and drain drum connection is in place and in good condition, and that it is coated with soft deflocculated graphite lubricating grease.

(e) Remove the screw cap from the bung of the drum and install the filling connection on the drum. To do this, the screw cap on the drum should be loosened very cautiously, and the drum allowed to vent, if necessary, before removing the cap entirely.

  Careless removal of the bung hole cap might result in spraying personnel present with the concentrated acid mixture.

(f) Connect the filling and vent hoses to the generator tank, first making sure that the ball check valve has been removed from the air line stop valve. The drum may be rolled over, if necessary, to facilitate these connections.

(g) Hoist the drum and the generator tank so that the tank stands vertically and the drum hangs with its axis horizontal, with the bung down, taking care that no strain is put on the filling or vent hoses.

(h) Open the two stop valves on the generator tank.

(i) Open the plug cock in the filling hose cautiously. If any water is present in the tank, a reaction of some violence may be expected, and smoke may be emitted from the orifice around the stem of the filling gage on the tank. If a reaction occurs, close the plug cock immediately. Do not open it again until all reaction ceases, and then with the same caution as before.

(j) Open the plug cock in the vent line cautiously.

(k) Permit the liquid to flow while watching the filling gage vigilantly. When the filling gage stem starts to rise, shut the plug cock in the filling hose immediately. Failure to do so may result in the entrapment of smoke liquid in the filling line between the generator tank stop valve and the filling line plug cock, and in subsequent spillage of the smoke liquid. Also, the tank should never be filled beyond the 32 gallon limit which the gage is designed to indicate, as sufficient space must be left for possible expansion of the liquid in case the filled tank is later subjected to a considerable rise in temperature.

 

28
 
(1) After an interval of a few seconds, close the vent hose plug cock. Disconnect the vent hose from the generator tank, leaving the tank valve open to vent the tank. Cautiously break the joint between the filling hose and the generator tank, allowing any liquid which may be entrapped to drain into the tank. After completely disconnecting the filling hose, close both generator tank valves.

(m) Remove filling gage and replace the tank filling cap, making sure that its gasket is in place and in good condition, also that it is coated well with soft deflocculated graphite lubricating grease. If the filling gage is not to be used again immediately, immerse in sodium bicarbonate solution, rinse in fresh water, and then wipe dry.

(n) Remove any smoke mixture which may be present on the tank connections. As much as possible should be wiped up with dry cloth or waste which should be discarded immediately. A 5 per cent solution of sodium bicarbonate may then be applied, but none should be allowed to remain where it can later contact the smoke mixture, since such contact will produce a relatively insoluble white precipitate. Lower the generator and the bulk container, bung up disconnect the filling and vent connections, and replace the screw cap on the drum. Wash the drum around the bung with sodium bicarbonate solution, followed by water. If the filling equipment is not to be immediately re-used, open both plug cocks and wash thoroughly. Sodium bicarbonate solution may be used if entirely removed afterwards by a water rinse.

(o) In partially filling a tank from a partially empty drum, or in completing the filling of the tank with a second drum, the same procedure should be followed as when completely filling the tank from a single drum, except that water in the tank will be spent by the first smoke mixture entering.

  43. PRECAUTIONS TO OBSERVE

(a) The precautions set forth in Chapter 2 for bulk FS under "Handling," together with the following, should be carefully observed:

(b) Filling operations should be done in the open air, preferably under open sided cover, but in all events in a dry location protected from spray. (c) The equipment should be as cool as possible for the filling operations, especially the FS bulk containers, as FS fumes badly when hot and may spurt dangerously when the bung is open. To lessen this, drums should be vented before opening.

(d) All equipment should be thoroughly dry before commencing filling operations. The location where filling operations are performed should also be dry.

(e) Equipment should be thoroughly washed and dried after using to prevent corrosion due to the acid. Filling lines should be periodically tested hydrostatically at 50 pounds per square inch to detect any signs of deterioration.

(f) Buckets of water and soda solutions should be kept nearby to use in the event of an emergency.

(g) Personnel should wear acid-proof clothing, gloves, boots, and gas masks. Any personnel not so protected should always stay to windward of the filling operations.

OPERATION

44. To lay a smoke screen with the Mark 1 Smoke Screen Generator, the following operations are performed:

(a) Make sure that all eight valves at each generator, and all remote quick operating valves, are closed.

(b) Open the stop valve on the pressure side of the quick operating valve.

 

29
 
(c) Check possible leakage of the remote quick operating jettison valves by opening the bleeder valve in the air line to the release air cylinder. If leakage is indicated, leave this valve open enough to prevent pressure from building up in the air release cylinder.

(d) Drain water from the separator in the air line to the generator tanks.

(e) Immediately before laying a screen, first fully open the air valves, and then the smoke discharge valves of the generator tanks to be used.

(f) Then stand clear of the generator.

(g) Opening of the proper quick operating valves will now cause FS liquid to be sprayed from the nozzles of the selected tanks.

(h) It is possible to discharge FS from any tank singly, or from any combination of tanks simultaneously.

45. To lay a smoke screen from the Mark 2 or Mark 5 smoke screen tanks, it is necessary only (a) to carefully crack the CO2 valve until the pressure has risen to the desired value, and then to open the smoke exhaust valve. The rate of flow of the smoke mixture is controlled by the CO2 valve. The pressure should not be allowed to exceed 150 pounds per square inch.

(b) Check all working parts to make certain they are in proper operating condition.

(c) Make certain there are no leaks of either CO2, air, gas, or smoke mixture (the gas referred to is the SO3, that is in solution in the chlorosulfonic acid).

(d) See that the gas line does not contain any water.

(e) Make certain that no parts are corroded, especially the gas inlet valve and the ball check valves. Corrosion of these valves may be traced to a leaky inlet valve allowing

  smoke mixture to leak into the gas line. Whenever tanks are refilled, defective valves should be reworked or replaced.

(f) Be sure there is no accumulated paint, dirt, or other material in the emergency release carrier, inboard of any of the rollers mounted in the carrier rack, or between the holding down lugs and angles on the emergency release carrier and their mating parts on the carrier rack where the presence of foreign material might impede jettisoning the generators in case of an emergency.

(g) See that all paint is in good condition.

46. Upon conclusion of the screening operation, each tank should be washed at least three times by filling with water and then forcing the water out at a low pressure. This operation should be performed, however, only by men who are completely protected by acid-proof clothing. Care should be taken when water first enters the tank, as considerable reaction is to be expected at that time. Also, too great pressure should not be allowed to build up during the washing operation or spattering of the corrosive diluted FS may result.

47. Upon concluding a screening operation, the entire ship's structure adjacent to the tanks should be washed down with a fire hose. If other parts of the vessel have been exposed to its own smoke screen, or to the smoke screen of another vessel, those parts should also be washed down if practicable. If practicable, the tanks should be washed out first, since some emission of smoke, or spattering of liquid, or both, may be expected to occur during washing.

STOWAGE AND HANDLING

48. Stowage instructions for the 55-gallon bulk containers are applicable for the tanks of FS that compose the Mark 1, Mark 2, and Mark 5 Smoke Screen Generators.

 

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These instructions will be found in Chapter 2 of this pamphlet.

49. Aboard ship the generators should be stowed topside, but protected from the weather, sun, and spray. They should be kept as cool as possible. This is especially true for the CO2 bottles of the Marks 2 and 5 generators.

MAINTENANCE

50. Smoke screen generators and their associated equipment require constant attention for proper operation. Personnel responsible for the maintenance and operation of the generators should make periodic inspections to check on the following points:

(a) That all working parts are properly lubricated, especially the rollers, holding down lugs, and holding down angles of the carrier racks.

LAYING THE SMOKE SCREEN

51. POSITIONING THE SCREEN

The positioning of the screen is, of course, a practical mooring board problem, but the following points should be considered in arriving at a solution:

(a) The long axis of the screen will lie in the direction of the apparent wind at the generator, while the screen will move bodily in the direction of the true wind.

(b) To lay a screen parallel to an enemy formation, course and speed of the smoke layers must be chosen to give them an apparent wind whose direction is parallel to the enemy formation.

(c) To place a screen or cloud directly on a target and maintain it there for the maximum length of time, the apparent wind at the generator should have the same direction as the apparent wind at the target, and release of smoke should be commenced when

  the target bears from the generator in the reverse of the direction of the apparent wind. Then if the target does not change course or speed, the target and the cloud will meet at the apex of a triangle whose base is determined by the bearing and distance of the generator from the target at the time of commencing release of smoke, and whose sides are determined by the course and speed of the target and the velocity and direction of the true wind, and the target will pass through the entire length of the cloud without gain or loss of distance as to width of the cloud.

(d) The parallel screen is probably most generally useful, but for the special purpose of covering a part of the enemy battle line with a screen while fire is concentrated on the remainder, the method of (c) should be used. Then, unless the enemy makes a considerable change of course or speed, the screen will hold practically the same position across the enemy line until the entire length of the screen has passed over the line.

52. EFFECTIVENESS OF THE SCREEN

Assuming that the screen is correctly placed to accomplish its intended purpose, its effectiveness is determined by its density as laid and, to a certain extent, by the weather conditions at the time.

(a) As the atomized FS smoke mixture leaves the nozzles of the generator it combines with the moisture of the air to form finely divided fog particles. Heat is evolved as this combination takes place, and the mixture of fog particles and air being thus warmer than the surrounding air tends to expand horizontally to a certain extent, and, to a greater extent, to rise. The horizontal expansion of the cloud has a negligible effect on the efficiency of the screen since the obscuring value of a cloud depends only on the total number of particles between the eye

 

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and the object, and it does not matter whether they are concentrated in a small space or spread out over the entire distance between the eye and the object. The rise, on the other hand, reduces the number of fog particles near the surface and hence tends to reduce the horizontal obscuring power of the screen. Normally, the rise will continue for a distance of from 1000 yards to 2000 yards to leeward of the generator and the screen will reach a height of from 200 feet to 300 feet and there level off.

(b) Unusual weather conditions may affect the normal behavior of the screen in several ways. If the moisture content of the air is very low, it may be insufficient to combine with all of the FS atomized and the screen will therefore be thinner than normal. Experiments over ice and snow covered ground in very cold weather have shown some thinning of the screen from this cause. Similar experiments over water have not been made, but it is believed that such conditions will seldom be encountered at sea. Again, very high winds have a tendency to tear holes in the screen and scatter it. And, third, there is the effect of convection currents. If present, they of course increase the tendency of the cloud to rise and become thinner near the surface. However, they are less frequently present over water than over land. They must be taken into account when it is desired to lay a screen on a beach. Thus, during the day, when the sun is shining and the ground is considerably warmer than the air, it may happen that convection currents along the beach will dissipate the screen, whereas at night and in the early morning the ground is frequently cooler than the air, and the screen will tend to settle closer to the ground.

(c) As to density, it is obviously wasteful and undesirable to expend more smoke mixture than necessary to accomplish the intended purpose. A good criterion of a satisfactory

  screen is considered to be not that it is absolutely without holes or thin spots, but rather that gun fire through it by direct view is impracticable. Experience to date with both aircraft and destroyer screens indicates that a density corresponding to from 10 to 13 gallons of smoke mixture per 1000 yards of screen will be satisfactory under all usual conditions.

53. DENSITY OF THE SCREEN

The density of the smoke cloud produced by any smoke generator is determined by the amount of smoke mixture discharged in unit time, and the velocity of the apparent wind at the generator.

(a) The general formula for density is as follows:

R = DW/30, in which

R = Rate of discharge of smoke mixture in gallons per minute,

D = Density of screen in gallons of smoke mixture per 1000 yards of screen, and

W = Velocity of apparent wind at the generator in knots.

Substituting for D the figure 10, we find that to lay a screen of density 10 gallons per 1000 yards requires a discharge rate of one-third gallon per minute per knot of apparent wind.

(b) The discharge rates of a standard nozzle have been established experimentally for pressures between 70 and 150 pounds per square inch, and for the nozzle retainer (see Figure 5, page 19) set up all the way and backed off two turns. These rates are shown graphically by the "Discharge Chart" (see page 33), which shows the discharges of from one to eight nozzles in gallons per minute. For each number of nozzles, 1 to 8, the lower full or unbroken line shows discharges with the nozzle retainers set up all

 

32
 
the way; the upper dotted or broken line shows discharges with the nozzle retainers backed off two turns. For each number of nozzles, the upper and lower discharge lines are connected by crosshatching to facilitate the reading of the chart. On the chart there is also a scale marked "Apparent Wind" which shows the number and setting of nozzles necessary to provide a screen having a density of 10 gallons of mixture per 1000 yards of length, at various pressures, and for apparent winds up to about 60 knots.

(c) As an example of the intended use of the discharge chart, assume an apparent wind velocity of 30 knots: Entering the chart along the 30 knot wind line, it is shown that a screen of a density of 10 gallons per 1000 yards can be achieved by the use of 6 nozzles set up all the way with an air pressure of 82 pounds per square inch; or by 5 nozzles set up all the way with an air pressure of 125 pounds per square inch; or by 5 nozzles backed off two turns with an air pressure of 90 pounds per square inch; or by 4 nozzles backed off two turns with an air pressure of 150 pounds per square inch. (It is not suggested that pressures or nozzle settings be varied in service to attain particular theoretical discharge rates, but it is presumed that different pressures may be available in different vessels, or in the same vessel at different times; and that different combinations of pressures and nozzle settings may be considered advantageous by various units, or may be so indicated for different climatic conditions.)

(d) If it is desired to lay screens of a density other than 10 gallons per 1000 yards, multiply the actual apparent wind by the ratio of the desired density in gallons per 1000 yards to 10. For example: Having an actual apparent wind of 20 knots, and desiring a density of 15 gallons per 1000 yards, divide 15 by 10 and multiply by 20, giving 30. Enter the chart at the 30 knot apparent

  wind line. If the combination of apparent wind and desired density is beyond the range of the chart, divide the apparent wind by 2 and multiply the number of nozzles indicated by the chart by 2.

(e) Whenever it is necessary to use more than one tank to obtain the desired density, all tanks used should be discharged at the same time. This is equally true whether they are carried on one ship or on several ships. In other words, when two or more ships are detailed to lay a certain screen, they should take formation so their individual screens will lie as close together as practicable, and all should discharge their assigned number of tanks simultaneously.

(f) It is obvious that the length of screen which can be laid with one smoke screen generator, Mark 1, depends on the density used. Since each tank of the generator holds about 32 gallons of smoke mixture, one tank will produce 3200 yards of screen of a density of 10 gallons per 1000 yards; hence one generator will produce 12,800 yards of such screen. With higher density, the length will be reduced in proportion.

TO JETTISON A GENERATOR

54. To jettison a generator, the toggle pin which prevents movement of the carrier latching hook must first be removed. The emergency release carrier, with the generator tanks mounted thereon, may now be released either by opening the remote quick operating release valve, or by pulling the release lever away from the generator with a smart pull, first having released the detent by pushing the button in the top of the lever. The quick opening valve should not be operated until the toggle pin has been removed, since the application of air pressure to the release air cylinder before removal of the toggle pin will probably lock that pin in place and necessitate bleeding down the

 

33
 

Discharge Chart

 

34
 
release air cylinder to permit its removal. The emergency release carrier, when thus released, is free to roll overboard under the influence of gravity. Air lines are not   automatically closed upon jettisoning of a generator; therefore, after a generator has been released, the two quick operating valves pertaining thereto should be closed.
 

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This page is blank.
 

36
 

Figure 11-Mark 2 and Mark 6 Smoke Screen Generators Installed for Use
Figure 11-Mark 2 and Mark 6 Smoke Screen Generators Installed for Use

 

37
 
FS GENERATORS   OP 1042

CHAPTER 4

GENERAL

55. There are two smoke screen generators designed to use FM for the generation of smoke screens from surface vessels. The Mark 4 Smoke Screen Generator is essentially four syphon bottle tanks mounted as a unit, and each holding 22 gallons of FM with CO2 as the dispersing pressure agent. This generator is designed for use on destroyers or larger vessels. For smaller vessels, especially P. T. boats, the Mark 6 Smoke Screen Generator hats been designed. This is similar to the Mark 4 generator except that it contains only one tank.

THE MARK 6 SMOKE SCREEN GENERATOR

56. The Mark 6 Smoke Screen Generator consists of a smoke screen tank Mark 2, fitted with a manual control valve and an exhaust tube designed to operate with or without one of four different sized nozzles. Integral with the valve is a syphon tube extending into the tank and converting the tank into a steel syphon bottle.

57. The smoke tank Mark 2 is a commercial ICC-3A480 full spun steel ammonia cylinder with a capacity of about 33 gallons. It is designed for a working pressure of 480 pounds per square inch, and is tested at 800

  pounds per square inch. The valve is brass, with a copper syphon tube sweated into it with soft solder. The exhaust tube is stainless steel, and the four nozzles are brass. Chained to the exhaust tube is a rubber cap, which fits onto the end of the tube, or onto any of the nozzles to prevent water from entering the tube when the generator is not in use.

58. Smoke screen control is obtained by the choice of the nozzle used. The rate of discharge varies with the size of the nozzle. The discharge time also varies with the

 

38
 

Figure 12-Mark 6 Smoke Screen Generator-Mounted
But Immediate Use Not Contemplated
Figure 12-Mark 6 Smoke Screen Generator-Mounted But Immediate Use Not Contemplated

 

pressure, and therefore with the temperature. As an example, the discharge time with the No. 42, the smallest, nozzle is about 25 minutes at 45°F and only 12 3/4 minutes at   approximately 75°F. The following table of discharge time versus nozzle size, however, is fairly accurate at temperature around 75°F.

 

Nozzle No.
Old Designation
New Designation Rated Time
of Discharge (Min.)
42 5 12 3/4
35 4 8
30 3 5 3/4
13 2 3 1/4
Exhaust tube without a nozzle .. 2 1/4
 

39
 

Figure 13-Mark 6 Smoke Screen Generator
Figure 13-Mark 6 Smoke Screen Generator

Figure 14-Smoke Exhaust Equipment for Mark 6 Generator
Figure 14-Smoke Exhaust Equipment for Mark 6 Generator

 

40
 

Figure 15-Mark 4 Smoke Screen Generator
Figure 15-Mark 4 Smoke Screen Generator

 

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DESCRIPTION OF THE MARK 4 SMOKE SCREEN GENERATOR

 

59. The Mark 4 Smoke Screen Generator is essentially four Mark 6 generators mounted on a single frame. It is for use on such vessels as destroyers. Therefore, all instructions and precautions given for the Mark 6 generator are equally applicable to each unit of the Mark 4 smoke screen generator.

FILLING INSTRUCTIONS

60. GENERAL

The filling of the Mark 4 and Mark 6 smoke screen generators is the same, except that with the Mark 4 generator there are four tanks to fill. Each tank is filled in two steps: First, 310 pounds (22 gallons) of FM or modified FM are poured into the tank, then 16 pounds of CO2 are added. Either Navy Filling Equipment Mark 1 Modification 4 or improvised equipment may be used for the FM filling. If the Navy equipment is used, the strainer should first be removed. The CO2 filling line may be similar to the one used to refill fire extinguishers except that one end must be modified to fit the generator valve at the exhaust tube connection. This line should include a flow pump if possible, otherwise gravity flow may be used with the CO2 cylinder raised a few feet above the generator tank.

  61. AGENTS

The FM or modified FM will be available in 55-gallon steel drums. Each drum has two openings with standard pipe threads, a three-fourths inch opening at one end and a two inch opening in the side. The CO2 is most likely to be provided in 50 pound lots in cylinders. Only liquid CO2 should be used.

62. FM FILLING EQUIPMENT

(a) The Navy Filling Equipment Mark 1 Modification 1 is the modification of the filling equipment designed for filling the Mark 2 smoke tank. This equipment utilizes the two inch opening in the drum, and is a completely closed system, venting back into the drum. Due to the presence of resinous titanium hydrate in the FM it is necessary to remove the strainer from this equipment before it can be used. The filling set up for using this equipment is shown in Figure 16.

(b) Improvised filling equipment: The improvised filling line recommended for use in the event that the Navy Filling Equipment Mark 1 Modification 4 is unavailable consists of the following: one bushing, 3/4 x 1/2 inch; three nipples, 1/2 x 6, 1/2 x 6, and 1/2 x 15 inches; one street ell, 1/2 inch; one valve, 1/2 inch. This set-up is shown in Figure 17.

 

42
 

Figure 16-Transferring FM to Generator
Figure 16-Transferring FM to Generator

(c) Whatever filling line is used, the following additional equipment will be needed: Platform scales, capacity 1000 pounds; block and tackle, or some other rig and hoist capable of lifting the FM drum (weight 850 pounds); safety equipment for personnel, to include acid-proof aprons and gloves, goggles, Bask masks if filling operation is to be performed under cover, and buckets of water and 5 per cent soda solution.

 

Figure 17-Alternate Method
Figure 17-Alternate Method

63. FM FILLING INSTRUCTIONS

(a) The filling line, valve, and generator tank should be thoroughly inspected to ascertain that they are completely dry.

(b) The filling line valve should be closed, and after the FM drum has been vented and the correct opening plug removed, the line should be screwed into the drum opening. The Navy equipment is designed to be screwed into the two inch opening, the improvised line into the three-fourths inch opening.

 

43
 

Figure 18-Arrangement for Transferring CO2 (Motor Driven Pump)
Figure 18-Arrangement for Transferring CO2 (Motor Driven Pump)

 

(c) The generator, with the valve and syphon tube removed, should be stood upright on the platform scales.

(d) The FM drum, with the filling line down, should be hoisted up until it is sufficiently high above the generator tank so that the filling line will be vertical when connected to the tank (Navy equipment) or in position with the long nipple extending into the tank (improvised equipment), as shown in Figures 16 and 17.

(e) The plug should be removed from

  the other opening if the improvised line is used, but this will not be necessary if the Navy equipment is being used.

(f) The scales should now be balanced to obtain the tare weight. Then they should be reset for a weight equal to 310 pounds plus the tare.

(g) The filling line valves should be carefully opened, and FM allowed to flow into the generator tank until the scales again balance, indicating that 310 pounds of FM have entered the generator.

 

44
 

Figure 19-Arrangement for Transfer of CO2 Alternate (Gravity) Method
Figure 19-Arrangement for Transfer of CO2 Alternate (Gravity) Method

 

(h) The valves should be closed and the filling line disconnected from the generator.

(i) The valve and syphon tube should be re-attached to the generator, and the generator should be placed aside until time to add the CO2.

(j) The filling line should be removed from the FM drum when filling operations are completed, or when the drum is empty. When filling operations are completed, the filling equipment should be thoroughly washed and dried.

  64. CO2 FILLING LINE

(a) There are two possible filling lines for CO2 one for gravity filling, the other for filling when using a motor driven pump.

(b) Equipment needed for CO2 filling by the gravity method consists of:

(1) Tilting rack for Mark 2 tank.

(2) 1000 pound capacity platform scales.

(3) Tilting rack for CO2 cylinder.

(4) Standard 50 pound CO2 cylinder, filled.

 

45
 
(5) Special U. S. Navy strainer adapter one-half inch, IPS threaded.

(6) Copper asbestos washer.

(7) Coupling adapter nut.

(8) By-pass valve.

(9) Coupling adapter.

(10) Flexible hose, 3 feet long.

(11) Flexible hose, 6 feet long.

(12) Adapter to connect discharge line to generator tank.

(13) 1000 pound capacity pressure gage.

(c) Equipment needed for the CO2 filling with the motor driven flow pump is as follows:

(1) Tilting rack for Mark 2 tank.

(2) 1000 pound capacity platform scales.

(3) Tilting rack for CO2 cylinder.

(4) Standard 50. pound CO2 cylinder, filled.

(5) Special U. S. Navy strainer adapter, one-half inch IPS threaded.

(6) Copper asbestos washer.

(7) Coupling adapter nut.

(8) Coupling adapter.

(9) Flexible hose, 3 feet long.

(10) Lux recharging pump assembly.

(11) Motor for recharging pump.

(12) Shut off or blow off valves (two required).

(13) Connector.

(14) Nipple.

(15) Copper asbestos washer.

(16) Coupling nut.

(17) Controller, magnetic type.

(18) Push button station.

(19) Wiring diagram.

(20) Flexible hose, 6 foot length.

(21) Adapter to connect discharge line to the tank.

(22) 1000 pound capacity pressure gage.

(23) 115 volt electricity for pump motor.

  65. FILLING INSTRUCTIONS FOR CO2

(a) Replace the exhaust valve and syphon tube in the generator tank and secure the tank to the rocker support on the balance scales.

(b) Connect the filling line to the CO2 cylinder, and to the generator tank at the exhaust to the connection (see Figures 18 and 19).

(c) If there is no flow pump in the line, the CO2 cylinder will have to be secured to a platform support a few feet above the top of the generator. The set-up at this stage in the operations is shown in Figure 19 (it should be noted, though, that in the illustration the two tanks are shown on the same level).

(d) Balance the scales to obtain the tare weight, and then reset the scales for a weight equal to the tare plus 16 pounds.

(e) Open the generator valve and then very carefully crack the CO2 valve (and start the flow pump if there is one in the line) allowing the CO2 to flow into the generator tank.

(f) The CO2 should flow into the tank until the scales balance, or until the pressure in the CO2 time gage indicates that a pressure of 480 pounds per square inch has been reached. The pressure must never be allowed to exceed 500 pounds per square inch.

(g) If the pressure reaches 480 pounds per square inch before all 16 pounds of CO2 have entered the tank (as will usually happen unless the equipment is very cool), the CO2 cylinder valve should be closed (after the pump, if present, has been shut off) and the tank rocked vigorously until the pressure has ceased to drop.

(h) This process (paragraphs e, f, and g) is repeated until the scales balance, indicating that all 16 pounds of CO2 have entered the cylinder.

 

46
 
(i) If it is impossible under existing temperature conditions to get all the 16 pounds of CO2 into the cylinder and still remain in the pressure limits allowed, the equipment and the agents will have to be cooled before the rest of the CO2 can be loaded into the tank. The temperature should be 110°F or less, if possible, for the filling operations. Temperatures under 85°F are preferred.

66. PRECAUTIONS TO TAKE DURING FILLING OPERATIONS

(a) The generator and FM filling line must be completely dry for the filling. The line should be washed and dried at the conclusion of filling operations. There must be no strainer in the FM filling line.

(b) Care should be taken to prevent the spilling of FM solution, especially on personnel.

(c) FM spilled on one's skin should be immediately wiped off, and the cloth or waste used disposed of, and the contaminated parts should be washed with an excess of water and then 5 per cent sodium bicarbonate solution.

(d) FM spilled on the deck, floor, or equipment should be thoroughly washed with water, soda solution, and then water again.

(e) Generators should be filled in the open, or if possible under open-sided cover.

(f) The filling locality should be completely dry.

(g) Personnel should wear acid-proof clothing, gloves, and boots. If the operations are carried out under cover, personnel should wear gas masks; otherwise, goggles will suffice.

(h) Hot CO2 cylinders may explode. Even CO2 from cool cylinders, if loaded into hot FM, will rapidly expand, creating a high

  pressure. Therefore, the agents and equipment should be kept as cool as possible, and should never be left in the sun just prior to filling.

(i) Care should always be taken during the addition of CO2 especially in hot weather, due to the possibility of obtaining too high pressures. The pressure should never be allowed to exceed 500 pounds per square inch.

OPERATION

67. To ready the FM generators for operation, the steps are as follows:

(a) Remove the transit caps.

(b) Remove the valve flared sealing caps.

(c) Screw exhaust tubes into valves.

(d) Choose correct jets and screw into exhaust tubes.

(e) Cover jets with rubber jet covers.

(f) Attach the valve handles.

68. To generate smoke, it is merely necessary to open the valves. The rubber jet caps will blow of due to the pressure. Being chained to the exhaust tubes, they will not be lost.

69. To stop generating smoke, close the valves and place the rubber jet caps back on the jets. Do not use force on the valves.

STOWAGE AND HANDLING

70. The tanks that compose the Mark 4 and Mark 6 Smoke Screen Generators are stronger and more leak proof than the 55-gallon bulk containers. Therefore, the instructions given in Chapter 2 for the stowage of bulk containers are applicable to the generators.

71. Aboard ship, FM generators should be stowed topside, but protected from the weather and sun. They should be kept as cool as possible.

 

47
 
72. When use of the FM generators is not contemplated, they should have their transit caps on. When use is contemplated and the exhaust tube and nozzle are in place, the nozzle cap should be kept on to prevent any water from entering the nozzle and exhaust tube. This cap does not have to be removed before the generator is used; the pressure in the generator will blow it off when the valve is opened.

MAINTENANCE

73. After use, at sea, the rubber nozzle cap will be ample protection for the exhaust tube. It must be replaced on the nozzle after use and kept there whenever the generator is not being used, however.

74. The only parts to be serviced are the

  valve, exhaust tube, and nozzles. They should be kept clean, and the threads oiled or greased.

75. After the unit is used, and when time and conditions permit, the smoke exhaust tube should be removed and thoroughly washed and dried.

76. When the exhaust tube is not attached to the valve, the transit cap should be screwed on to protect the valve.

77. After use, at the time the exhaust tube is being washed, the valve outlet end should also be washed. Fresh water is preferred but not a necessity.

78. In cleaning, care should be taken to prevent damage to the flared seat and threads.

 

48
 

Figure 20-Smoke from Smoke Screen Generator Mark 3
Figure 20-Smoke from Smoke Screen Generator Mark 3

 

49
 

CHAPTER 5

 

GENERAL

79. The Navy HC Smoke Screen Generator Mark 3 was designed to generate smoke from small craft, primarily landing and

  landing support craft, where weight and space are at a premium. The entire generator weighs only about 165 pounds, and extends completely abaft the stern. It will generate smoke for from five to six minutes when all pots are used simultaneously, as will be the case under normal operation.
 

50
 

Figure 21-HC Smoke Screen Generators in Operation
Figure 21-HC Smoke Screen Generators in Operation

Figure 22-Smoke Screen Generator Mark 3 on Rack
Figure 22-Smoke Screen Generator Mark 3 on Rack

 

51
 

Figure 23-Mark 3 Smoke Pot
Figure 23-Mark 3 Smoke Pot

 

DESCRIPTION

80. The HC Smoke Screen Generator Mark 3, shown in Figures 21 and 22, consists of four Mark 3 smoke screen pots carried in the Mark 1 smoke screen rack. The rack is mounted on the stern of the boat, extending back over the water. A release lever in the rack allows the immediate jettisoning of the pots in the event of an emergency.

(a) Each pot is a metal can, approximately 8 1/2 inches in diameter and 9

  inches high, containing about 32 pounds of smoke mixture. On the top is a handle attached to a tear strip. The removal of the tear strip reveals the igniter button and an envelope containing the ignition match held in place by a clip spring. The pots, shown in Figure 23, are water, vapor, and moisture proof.

(b) The supporting rack is a cold rolled steel base plate, in which four equally spaced holes are cut, with a cylindrical cage of steel uprights and hoops at each hole to hold the

 

52
 

Figure 24-Release Lever Details of HC Smoke Screen Generator
Figure 24-Release Lever Details of HC Smoke Screen Generator

 

Figure 25-Method of Mounting Mark 3
Generator on Landing Boat
Figure 25-Method of Mounting Mark 3 Generator on Landing Boat

smoke pots. Arms extending from a discharge shaft form the bottoms of the cages. These arms may be dropped, allowing the pots to fall out, by raising a release lever that is attached to the center of the discharge shaft. To prevent premature jettisoning

 

Figure 26-Alternate Method of Mounting
Mark 3 Generator
Figure 26-Alternate Method of Mounting Mark 3 Generator

of the pots, the release lever is held down by a safety latch, shown in Figure 24. Actually, when the latch is removed from safe position, the weight of the pots on the shaft arms is sufficient to force them down and let the pots fall into the water. Two steel pads

 

53
 
welded to the bed plate serve to mount the rack on the mounting pads supplied for the boat.

INSTALLATION

81. Methods of mounting the rack on to the boat are shown in Figures 25 and 26. Whatever method is used, the mounted rack must extend back over the stern sufficiently to allow the pots to fall freely into the water when jettisoned.

(a) Normally, the two mounting pads are to be fastened permanently to the deck at the stern of the boat. The rack pads may then be bolted to the mounting pads when it is desired to mount the rack to the boat. This arrangement permits the rack to be easily removed when use of the generator is not contemplated.

(b) In the event the shape of the stern obstructs the fall of the pots on jettisoning when the rack is mounted as instructed above, an alternate method of mounting must be improvised. A suggested method is to bolt the rack pads to the ends of "two by four" channels about three feet long, the other ends of which are fastened to the deck at the stern of the boat by steel brackets.

OPERATION

82. To put the smoke screen generator in operation after the rack has been mounted, the release lever is first pulled down and held in place by putting the latch in safe position. The pots are then put into the cages, as shown in Figure 24. When the proper command has been given, the tear strip handle on top of each pot is given a quick jerk to remove the tear strip, as shown in Figure 27. Next, the envelopes are removed from the clips, the matches taken out (see Figure

  28), and the ignition buttons scratched by the matches (see Figure 29). This will ignite the starter-mix, which will burn through the zinc cup, as shown in Figure 30, to ignite the smoke mixture and produce the smoke screen shown in Figure 31. The pots should be ignited in order, either from left to right, or from right to left. An effort should be made to get all the pots ignited before the first pot has started to produce smoke.

(a) If a screen of less density than that produced by all four pots operating simultaneously is desired, one, two, or three pots, instead of all four, may be put in operation.

MAINTENANCE

83. When not in use, the pots should be stowed in a location protected from the weather, but convenient for jettisoning. They should never be stowed below deck.

SPECIAL PRECAUTIONS

84. In view of the fact that the smoke mixture is subject to spontaneous combustion on contact with moisture, care should be taken when handling the pots to preserve their water-tight integrity. When in operation, the pots become very hot therefore inflammable substances should not be permitted near the rack. In the event of an emergency, all pots in the area can be simultaneously jettisoned by pulling the release latch from the safe position.

(a) Although HC smoke is harmless in the concentrations found in a smoke screen in the open, it is somewhat toxic when concentrated, as when generated below deck or in some other confined spaces. Therefore, in such cases, gas masks should be worn, whereas normally none are needed.

 

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IGNITING A MARK 3 SMOKE SCREEN POT

Figure 27-Jerking Open the Tear Strip-Note the Envelope That Contains the Match
Figure 27-Jerking Open the Tear Strip-Note the Envelope That Contains the Match

Figure 28-Removing the Match from the Envelope
Figure 28-Removing the Match from the Envelope

 

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Figure 29-Scratching the Igniter Button
Figure 29-Scratching the Igniter Button

 

Figure 30-Starter Mixture Burning
Through Zinc Cup
Figure 30-Starter Mixture Burning Through Zinc Cup

 

Figure 31-Pot in Operation
Figure 31-Pot in Operation

 

56
 
This page is blank.
 

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HC SMOKE FLOATS OP 1042

CHAPTER 6

 

GENERAL

85. The smoke floats now used by the Navy are the Smoke Float Mark 1 and the Floating Smoke Pot M4. Both of these floats are being revised, and the revised munitions will be called the Smoke Float Mark 2 and the Floating Smoke Pot M4A1, respectively. The revisions will not greatly alter the operation of the munitions, and they will be discussed later in this chapter. The Smoke Floats Mark 1 and 2 are designed for use on, or from, merchant vessels and convoys escorting vessels for anti-submarine defense. The floating smoke pots are primarily for the use of the amphibious forces.

  SMOKE FLOATS MARK 1 AND 2

86. DESCRIPTION

(a) The smoke float Mark 1 is a cylindrical float, 22.5 inches in diameter and 30.7 inches high. It consists of an igniter, an HC container, a buoyancy chamber, and a metal skirt, to give it floating stability. The HC container is filled with 90 pounds of HC mixture, which gives a smoke cloud for 18 to 21 minutes. The complete float weighs about 165 pounds. Holes in the buoyancy chamber permit sufficient water to enter this chamber to sink the float in approximately 45 minutes, or about 25 minutes after the float has finished generating smoke.

 

58
 

Figure 32-Smoke Float Mark 1 Ready for Operation
Figure 32-Smoke Float Mark 1 Ready for Operation

Figure 33-Smoke Float Mark 1
Figure 33-Smoke Float Mark 1

 

59
 
(b) The igniter is a pull wire igniter that is designed to screw into the threaded hole in the center of the top of the float. This hole is protected by a cap when the float is to be used. The igniter is packed in a separate container to prevent deterioration before use. This container is secured to the top of the float.

(c) The Mark 2 smoke float is identical to the Mark 1 float, except that its body has been slightly revised to aid production. This gives the float a slightly more streamlined appearance than the Mark 1 float, but the method of operation and the operation characteristics are identical.

87. METHOD OF USE

Although designed to be dumped overboard as a float, these generators may also be mounted for use on the deck. For this purpose, they should be mounted on metal topped racks or platforms rigged on the weather deck as far aft as practicable. These platforms should be about 18 inches above deck level and hinged to allow jettisoning of the floats in the event of an emergency. The Bureau of Ships will provide specific data as to the type of platform to be employed.

88. OPERATION

To fire the smoke float, it is first necessary to replace the igniter, which, to prevent deterioration, has been packed in a separate container secured to the top of the smoke float. At the center of the cover is a threaded hole protected by a cap. This cap is removed, and the igniter taken out of its container and inserted into the threaded hole. A green cap on the igniter protects the toggle on the puller from damage or accidental ignition. This is removed, and the toggle pulled quickly all the way out. If the starter has functioned properly, a small flame and a stream of smoke will be emitted

  immediately from the hole left by the igniter wire. Approximately 25 seconds after the toggle has been pulled out, the smoke mixture will ignite. Inasmuch as the ignition and first emission of smoke is rather violent, personnel should be warned to stand clear of the smoke float as soon as the toggle has been pulled out.

89. STOWAGE AND HANDLING

In view of the fact that the smoke mixture is subject to spontaneous combustion on contact with moisture, care should be taken when handling the containers to preserve their water-tight integrity. When not in use, they should be stowed on the weather deck in a location convenient for jettisoning, but protected from the weather. They should never be stowed between decks. For reasons of safety, and to prevent deterioration of the igniter, this unit should be inserted in the smoke float only when ready for firing. Since the smoke floats become very hot when in-operation, if the floats are to be operated on deck all inflammable material should be moved a safe distance away before the float is ignited, and a fire hose should be led out, with pressure on the fire mains. The precautions given under HC in Chapter 2 should also be observed.

FLOATING SMOKE POT M4 AND M4A1

90. DESCRIPTION

(a) The floating smoke pot M4 (see Figure 35) is a cylindrical pail, the bottom third of which is filled with HC smoke mixture. In the cover are vents, from which the smoke is ejected. The pot will produce smoke for from 10 to 15 minutes.

(b) The cylindrical pail is 13 inches high and 12 1/6 inches in diameter. It is hot rolled steel, with a lug cover of the same material. The cover is held in place by a five-eighths

 

60
 

Figure 34-Floating Smoke Pot M4A1
Figure 34-Floating Smoke Pot M4A1

Figure 35-Floating Smoke Pot M4
Figure 35-Floating Smoke Pot M4

 

61
 
inch wide steel strap, which is secured by a steel connector. A wire handle is attached to the sides. The cover has three equally spaced vent holes 23/32 inch in diameter to provide outlets for the smoke. Also in the center and near the center are two 3/32 inch holes, one for the fuze pull wire and the other for the fuze support nail. All of these holes, and the protruding part of the fuze pull wire, which is kept bent down flat on the cover, are covered with water-proof adhesive tape.

(c) The fuel chamber is enclosed with a cellulose acetate disk above and another below. The upper disk is held in place by a flanged steel retaining ring, and has a one-fourth inch hole in the center for the passage of the safety fuze. To seal this point, a five-eighths inch strip of water-proof tape is wrapped around the base of the safety fuze and the area coated with water-proof shellac. The starter cup, also of cellulose acetate, fits into a recess in the center of the top layer of filling.

(d) The ignition system is a safety fuze with a fuze lighter and a pull wire. When pulled, the pull wire ignites the fuze lighter, which is essentially a match, and this ignites the starter mixture, which burns through the cup and ignites the smoke mixture. The fuze, fuze lighter, and bottom half of the pull wire, are stapled to a soft wood fuze support which is held in place by the fuze support nail.

(e) The floating smoke pot M4 has recently been redesigned. The new pot has been designated the floating smoke pot M4A1, and will be the same as the M4 pot, except that the ignition system has been redesigned to provide a more rugged set-up. The alterations include adding a metal retaining disk on top of the cellulose acetate

  fuel retaining disk, replacing the safety fuze with a delay train, and replacing the pull wire igniter with a bouchon fuze.

91. METHOD OF USE

The primary use of this float is to cover landing operations in the face of enemy fire. The float may be used as a pot or candle, or as a float, whenever a smoke screen of modest dimensions is needed.

92. OPERATION

Within 24 hours of firing the smoke pots, the vent hole covers must be removed for five minutes and then replaced. Immediately prior to firing, the adhesive tape covering the pull wire is removed. The tape covering the vent holes and the fuze support nail is not removed. Then the fuze wire is given a sharp pull, and about 10 to 20 seconds later smoke will start. The pressure of the gases is sufficient to blow the tape off the vent holes.

93. PRECAUTIONS

(a) The tape from at least two of the vents must be removed for five minutes within the twenty-four hours preceding the firing of the pot. This precaution must be observed in order to prevent hazard to the operator when the pot is fired.

(b) Only the fuze pull wire tape should be removed when the pot is being put into operation. This tape should not be removed until immediately prior to firing the pot.

94. STOWAGE AND HANDLING

Instructions for stowage and handling are the same as for other HC munitions, and may be found in Chapter 2.

 

62
 

Figure 36-HC Smoke Pot M1 in Operation
Figure 36-HC Smoke Pot M1 in Operation

 

63
 
This page is blank.
 

64
 

Figure 37-- Smoke Pot M1
Figure 37-- Smoke Pot M1

 

65
 
SMOKE POTS, CANDLES, GRENADES OP 1042

CHAPTER 7

 

GENERAL

95. The following munitions are covered in this chapter:

(a) The HC Smoke Pot Mark 3. This pot is a component of the Smoke Screen Generator Mark 3.

(b) The HC Smoke Pot Ml. This pot is used whenever a small pot is desired. It is merely an enlargement of the smoke candles.

(c) The Navy HC Training Candle is for generating very small amounts of smoke, and is primarily designed for use in damage control practice.

(d) The HC Smoke Grenade AN-M8. This grenade, formerly designated as the HC smoke candle M11, is primarily used by the Navy as a distress signal. It may be used to generate a small smoke screen, however, and is therefore discussed in this pamphlet.

HC SMOKE POT MARK 3

96. The HC Smoke Pot Mark 3 is a component of the Mark 3 Smoke Screen Generator, and as such has been described in Chapter 5.

  THE SMOKE POT M1

97. GENERAL DESCRIPTION

Except for its smaller size, this pot is almost identical to the Mark 3 pot. It weighs 14.3 pounds, of which 12.5 pounds is smoke mixture. Burning time is from five to eight minutes. The pots may be ignited electrically as well as manually.

98. CONTAINER

The container is a 7 3/4 inch by 5 5/16 inch (diameter) can. The top has a 1 1/8 inch hole in the center, and it is crimped to the side along the upper edges. A cylindrical and flanged zinc cup for the starting mixture fits into the hole in the cover. In turn, it is covered with a cardboard disk, which has a one-fourth inch hole in it, through which protrudes the match head. The cover is fitted with a carrying handle, and is held in place with adhesive tape around the rim. The adhesive tape is held in place by a metal band encircling the container. A transverse metal strap passes over the handle and holds it in place.

 

66
 
99. METHOD OF IGNITION

The zinc cup previously mentioned is filled with starter mixture. Protruding through the cardboard cup cover is a match head. Under the cover is packed an envelope with a scratcher. The scratcher is used to scratch the match head which ignites the starter mixture, and this ignites the HC mixture.

100. MANUAL OPERATION

The smoke pot is prepared for operation just prior to firing. The metal strap and band and the adhesive tape are removed from the container, and the cover is taken off. The scratcher is taken out of the envelope and used to scratch the match head. About 10 to 20 seconds later the pot will start producing smoke.

101. ELECTRICAL FIRING

(a) Remove the cover as above.

(b) Withdraw the match head and insert the open end of an electric squib into the match head hole and tape it securely in this position. The squib may also be taped to the pot so that the flash will be communicated directly to the match head instead of to the starter mixture.

(c) In wiring, connect the squib wires of not more than twenty smoke pots in one electrical series, and connect the free ends of the first and the last squibs to a lead wire from the terminals of the exploder (e.g., Machine, Blasting, 100 caps), using Wire, Firing, L.P. or its equivalent, for the lead wire. Fire by operating the exploder in the usual manner. For training purposes, when exploders are not available, smoke pots may be fired by connecting pots to an automobile battery. If this method is used, best results will be obtained by wiring the pots in parallel.

(d) The following precautions should be

  taken when the pots are ignited electrically: The circuit should be tested by means of a circuit detector before firing to make sure that the circuit is intact. The metal cover should be laid in place over the squib and the match head or starter mixture to exclude moisture, but it should not be forced into position as this might damage the squib or cut the wires. Under no condition should detonators or blasting caps be used in place of squibs.

(e) NOTE.-An electrical squib is a small paraffined paper tube containing black powder. When ignited electrically, it produces a flash. An electric detonator is a copper tube of fulminate of mercury. It carries wires similar to a squib (i.e., two 4 to 6 foot wires).

102. STOWAGE AND HANDLING

Instructions for stowage and handling are given under "HC" in Chapter 2.

NAVY HC TRAINING CANDLE

103. GENERAL

The Navy HC Training Candle was developed for use in damage control practices. It is oval in shape, and is two inches high and two inches long by one inch wide. Due to the toxicity of concentrated HC smoke, this is the only munition small enough to generate HC smoke in confined places.

104. OPERATION

This candle is fired by removing the cover and scratching the match head with a scratcher.

105. STOWAGE AND HANDLING

Instructions for stowage and handling are the same as for the other HC munitions.

 

67
 

Figure 38- AN-M8 Smoke Grenade
Figure 38- AN-M8 Smoke Grenade

 

68
 
106. PRECAUTIONS

If liberated in confined spaces and allowed to remain for some time, HC may combine with moisture present to form hydrochloric acid in sufficient quantity to attack bright metal. Therefore, HC smoke candles should not be used in compartments in which delicate instruments, machine tools, or other precise equipment would be exposed.

HC SMOKE GRENADE AN-M8

107. GENERAL

The HC smoke grenade, as used by the Navy, is primarily a signaling device and, therefore, is classified as a pyrotechnic. At times, however, it may be desired to utilize this munition to generate smoke screening. This munition weighs approximately 1.75 pounds, and will produce smoke for 2 1/2 to 3 3/4 minutes.

108. DESCRIPTION

Referring to Figure 38, on page 67:

(a) The HC Smoke Grenade MS consists of a cylindrical tin container 2 5/16 inches in diameter and 4 1/2 inches high, containing solid HC smoke mixture, a starting mixture, and a fuze mechanism for firing. With the fuze attached, the height of the grenade is 5 3/4 inches.

(b) A zinc cup is placed in a depression in the top of the smoke mixture. The top of the cup is flanged outward. This flange covers the entire surface of the smoke mixture.

(c) The container top, in which there are four 0.25 inch holes covered by squares of

  adhesive tape, and to which a brass adapter is riveted, is fitted to the can on top of the zinc starter mixture cup. Into the brass adapter is assembled an M1 fuze in the older grenades, or an M200 fuze in the later grenades.

109. ACTION ON FIRING

When the safety pin of the fuze is pulled and the lever released, the striker fires the primer, igniting the delay element which in turn ignites the starting mixture. The starting mixture burns through the cup and ignites the smoke mixture.

110. OPERATION

Directions for the use of this grenade as a distress signal are listed in Ordnance Pamphlet No. 562. When used for other purposes, the following directions should be followed:

(a) Grasp the grenade in one hand, keeping the lever firm, and pull the safety pin.

(b) Release the lever and throw the grenade with a full arm swing, or place it on the ground. There is about a two second delay before the start of the production of smoke.

(c) Precautions. The grenade should not be thrown or placed within five feet of inflammable material. Personnel should remain at least five feet away from a smoking grenade.

111. STOWAGE AND HANDLING

Instructions are the same as for the other HC munitions.

 

69
 
WHITE PHOSPHORUS PROJECTILES OP 1042

CHAPTER 8

 

GENERAL

112. The 5"/38 caliber white phosphorus smoke projectiles were developed as a means of laying a smoke screen at a distance. By this method, the danger to the ship laying the screen is considerably decreased, and the location of the screen may be chosen at will. The success of the screen depends upon the accuracy of placing it.

113. Screens produced by these projectiles serve the same tactical uses as screens produced by any other method. This is a more flexible weapon than any other type of smoke apparatus, since a ship need not approach the enemy so closely and be exposed to point-blank fire. This projectile was not

  intended for use against aircraft, since its effective volume of burst is small. The effect of fragments is negligible.

DESCRIPTION

114. The smoke projectile is similar to the 5"/38 caliber illuminating projectile, Mark 30, except that the illuminating canister is replaced by the smoke canister. The empty canister is a light steel cylinder, approximately 12 inches long and 3.9 inches in diameter, fitted with a burster tube in its center 12 inches long and 5/8 inch in diameter. In loading, it is packed with 172 small metal tubes, three inches long and one-half inch in diameter, which serve to increase the

 

70
 

Figure 39-White Phosphorus Projectile
Figure 39-White Phosphorus Projectile

 

71
 
distance to which the smoke is spread from the point of burst. The canister, filled with tubes, is tested for leaks at 100 pounds per square inch air pressure, and then is filled with molten white phosphorus, which solidifies on cooling. The weight of the filled canister is approximately 14 pounds 11 ounces, containing approximately 7 pounds one ounce of WP. The complete projectile weighs approximately 52.7 pounds. The burster con-thins 12 grams of ballistite, fired by a short delay fuze. Thus, the functioning of the projectile is as follows: The mechanical time fuze ignites the expelling charge of black powder, which ejects the canister and ignites the short delay burster fuze. The canister is burst shortly after it clears the projectile case and showers the smoking tubes over a space approximately 150 feet in diameter and 150 feet high.

STOWAGE AND HANDLING

115. Since the canisters are tested at high pressure and are contained within the sealed projectile case, the projectiles present no great hazard as to stowage. However, since any leakage or malfunctioning in stowage would be accompanied by quantities of acrid smoke and fires which are difficult to permanently extinguish, the projectiles should be placed in improvised topside stowage which will lend itself to ready jettisoning of projectiles, if necessary. The stowage should provide protection from rain or spray, as well as from direct sunlight.

  USE

116. The screen should be laid so that bursts occur at heights of 25 to 50 feet above the water, and 35 to 40 yards apart. Bursts which occur higher than the recommended height may allow vision beneath the cloud, and those which strike the water are useless. Burning WP is readily extinguished by water. It should be remembered that the screen will drift at a rate equal to the velocity of the wind. Under normal conditions, the screen will be effective for seven minutes or more, but will, of course, drift with the wind. Range table information, for use in preparing initial firing data and in adjusting the height of burst during the firing, are given in Table 1. The elevations and fuze settings in columns 2 and 3 are computed to burst the canister along the line of sight. Any desired height of burst may be obtained by raising the elevation of column 2 in accordance with the information given in column 6.

PRECAUTIONS

117. WP burns at a relatively low temperature and is readily extinguished by water. However, due to its ability to ignite spontaneously when in contact with air, an extinguished fire may reignite when the WP dries out. A solution of a few per cent of copper sulfate in water will remove this danger and extinguish fires permanently. Refer also to Chapter 2, under White Phosphorus (WP).

 

72
 

TABLE 1

5 INCH 38 CALIBER GUN
BALLISTIC DATA FOR WHITE PHOSPHORUS PROJECTILE
45-Second Mechanical Time Fuzes Mk. 18, Mods.

Range Elevation Fuze
Setting
Effect of 0.2 Second
Increase in Fuze
Setting on
Change in Altitude
for 10 Minutes
Range Altitude Change in Elevation
Yards Minutes Seconds Yards Feet Feet
(1) (2) (3) (4) (5) (6)
400 20 0.4 167 -1 3
600 25 .7 164 -2 5
800 30 .9 161 -3 7
1000 36 1.2 158 -4 9
1200 42 1.4 155 -5 10
1400 47 1.7 152 -5 12
1600 53 2.0 148 -6 14
1800 59 2.2 145 -7 16
2000 66 2.5 142 -8 17
2200 72 2.8 139 -9 19
2400 79 3.1 136 -10 21
2600 86 3.4 133 -11 23
2800 93 3.7 130 -11 24
3000 100 4.0 127 -12 26
3200 108 4.3 124 -13 28
3400 116 4.6 121 -14 30
3600 124 5.0 118 -15 31
3800 13 25.3 115 -16 33
4000 141 5.7 112 -17 35
4200 150 6.0 110 -18 37
4400 159 6.4 107 -19 38
4600 169 6.8 104 -20 40
4800 179 7.2 102 -21 42
5000 189 7.6 99 -23 44
5200 190 8.0 97 -24 45
5400 210 8.4 95 -25 47
5600 222 8.9 92 -26 49
5800 234 9.3 90 -28 51
6000 247 9.8 88 -29 52
6200 260 10.2 86 -30 54
6400 273 10.7 83 -31 56
6600 287 11.2 81 -33 58
6800 302 11.7 79 -34 59
7000 317 12.2 77 -36 61
7200 333 12.7 75 -38 63
7400 349 13.3 73 -40 65
7600 366 13.8 72 -41 66
7800 384 14.4 70 -43 68
8000 402 15.0 68 -45 70

Note: These data are for standard Range Table conditions. Use O.P. 551, 5"/38 Cal. Range Table for differentials.
Columns 2 and 3 were computed to place burst along line of sight.
Height of burst may be varied by applying corrections to Column 2 in accordance with Column 6.

 

73
 
TABLE 2

OPERATING CHARACTERISTICS AND WEIGHTS
OF SHIPS CHEMICAL SMOKE MUNITIONS

1. Smoke Screen Generators
Munition Type
Smoke
Dimensions Total
Weight
(pounds)
Weight of Smoke Mixture (pounds) Time of Smoke Generation (minutes)
Mark 1 FS 38"h, 70"l, 32 1/4"w 3,198 2,048 6 1/2 to 85
Mark 2 FS 22"h, 68"l, 17"w 974 525 6 1/2 to 21
Mark 3 HC 12"h, 48 1/4"l, 17 3/4"w 165 128 5 to 6
Mark 4 FM 40 3/4"h, 58 1/2l, 36 1/2"w 2,403 1,250 2 1/2 to 100
(at 45°F)
Mark 5 FS 24"h, 68"l, 24"w 796 525 2 1/2 to 21
Mark 6 FM 17 1/2"h, 58"l, 18"w 544 330 2 1/2 to 25
2. Smoke Pots and Floats, etc.
Pot M-1 HC 9.5"h - 5 1/2" dia. 13.3 12.5 5 to 8
Pot Mark 3 HC 9"h - 8 1/2" dia 35 32 5 to 6
Floating pot M-4 HC 13"h - 12" dia 35 26 10 to 15
Floating pot M-4A1 HC 13"h - 12" dia 35 26 10 to 15
Smoke Float Marks 1 and 2 HC 30.7"h - 22.5" dia 165 90 18 to 21
Smoke Grenade AN-M8 HC 5 3/4"h - 2 5/16" dia 1.75 1.00 1 2 1/2 to 3 1/4
3. Smoke Projectile
5"/38 cal. WP (5"/38 cal. ill. proj.) 52.7 7 1/16 Burst

1 Approximate.

 

74
 
Requests for copies of this pamphlet should be addressed to the nearest BuOrd Publications Distribution Center.

 

Commandant and Superintendent
U. S. Naval Gun Factory, Navy Yard
Washington 25, D. C.

Officer in Charge
Ordnance Publications Subcenter
Naval Supply Depot
Pearl Harbor, T. H.

  Commandant
Navy Yard
Mare Island, California

Commander Service Force, Seventh Fleet
Ordnance Publications Subcenter
c/o Fleet Post Office
San Francisco, California

 
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