3101. It must be thoroughly understood that the attack plans outlined herein are primarily type plans which are intended to serve only as a guide. No multitude of written plans can replace initiative, resourcefulness, and good judgment which every motor torpedo boat officer must exercise in planning and launching an attack.
3102. In planning and developing an attack it is imperative that the attack commander have a thorough knowledge of the boats which he commands, their strong points and weaknesses, their possibilities and limitations. He must understand his officers and men and they in turn must understand him, in order that his plans will be carried out even when things go wrong and communications are disrupted. Team work and indoctrination are the keynotes to a successful attack.
3103. The attack commander should make use of all the inherent advantages which the PT boat possesses and avoid as far as possible their weaknesses. He should use stealth in closing the range before being detected. He should seek a favorable attack course where the speed of his boats can best be used, taking into account the desirability of reducing spray. He should consider the direction of the wind for carrying sound and laying smoke. He should make use of sun glare to blind the enemy and moonlight to silhouette him, at the same time avoiding being blinded and silhouetted himself. He should take advantage of the enemy being otherwise engaged and coordinate his attack with other units whenever possible. In short, he must make use of everything favorable to press home the attack to decisive range.
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CHAPTER 2. ATTACKS ON ENEMY MERCHANTMEN OR
AUXILIARIES
3201. In attacking a single unprotected enemy merchantman, transport or cargo vessel, the direction of attack is immaterial as the enemy is free to maneuver. In general, the boats engaged in the attack should press into decisive torpedo range, and the boat in the most favorable position should fire one or more torpedoes depending on the size of the vessel. Other boats should follow up the attack and fire torpedoes if necessary. Depth charges may be used to finish off a crippled vessel if torpedoes are not available.
3202. In attacking two or more unprotected enemy merchantmen, the same procedure should be followed as in attacking a single vessel except that boats of the attack force will pick "targets of opportunity", (targets which present themselves favorable for attacking) and will pursue enemy vessels should they scatter.
CHAPTER 3. ATTACKS ON ENEMY CONVOYS
3301. Daylight attack on enemy convoy or task force.-(a) Motor torpedo boats should be led in squadron formation(s) to favorable attack position (s) sharp on the bow of the convoy. At this point, the divisions should be released to press home simultaneously attacks, deploying as necessary to present a maximum multiplicity of targets. Divisions and individual boats will take advantage of opportunities as they arise and will pick their targets using normal distribution from van to rear. Here as never before, real teamwork comes into play in picking appropriate targets without encroaching on a flanking boat's territory.
(b) If it is possible, one or more divisions may be detached to attack the convoy from astern. This attack has a great advantage if it is timed a few minutes after the attack from ahead, to take advantage of any confusion and target maneuvers.
(c) If the wind is favorable (from ahead of convoy, or from attacking side), smoke should be used to screen the attack.
3302. Night attack on enemy convoy.-At night or in low visibility after reaching a favorable attack position, the individual boats should be released to press home their attack. There are two general plans for a night attack, the first, a mass attack which is similar to the daylight attack except that boats proceed independently; and the second, a wave attack where the
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FIGURE 15
39
FIGURE 16
40
FIGURE 17.
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FIGURE 18.
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FIGURE 19.
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first wave's attack is followed by a second wave which should try to attack at such a time as to take advantage of holes in the screen and enemy confusion caused by the first wave. If sufficient boats are available, a third wave may follow the second wave in attacking. First wave may renew the attack after last wave, if striking power is available.
CHAPTER 4. ATTACKS ON ENEMY TASK FORCES
3401. Unsupported attack on enemy task force.-The plans for attacking an enemy convoy apply equally to attacking an enemy task force, the only material difference being that stiffer resistance may be expected and a great number of boats should normally be employed.
3402. Supported attacks in fleet action.-This type of attack has such a wide range of possibilities which depend on so many factors that it is not possible to recommend any general plan. Some of the possibilities, however, are listed below.
(a) Night action with destroyer support where MTB's first attack the enemy screen, permitting destroyers to penetrate the screen and attack the - main body.
(b) Night action with destroyer or light cruiser support where the DD's and CL's engage the screen, permitting MTB's to pierce the screen and attack the main body.
(c) Day action where destroyers, aircraft and MTB's attack enemy main body simultaneously. MTB's launched from a carrier or operating from a fleet base.
3403. Attacks coordinated with aircraft.-Attacks by large numbers of motor torpedo boats and aircraft made simultaneously on enemy forces should be highly successful, as such attacks will present a great multiplicity of targets for enemy anti-aircraft and secondary batteries and will bring heavy striking power to bear on the enemy. The time of the attack will depend upon the motor torpedo boats, as aircraft can control their timing more readily. The aircraft attack may be a dive-bombing, strafing, or torpedo attack or any combination thereof. An aircraft torpedo attack, coordinated, should be made on opposite side from the MTB attack. A high altitude horizontal bombing attack will not divide the enemy's fire to the maximum extent, as he will not divert the use of his machine guns toward the bombers.
In this type of attack all available motor torpedo boats should attack simultaneously.
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3404. Use of aircraft parachute flares at night.-At night parachute flares dropped by aircraft on the opposite side of the enemy from approaching motor torpedo boats, would be very useful. These flares would attract the enemy's attention and would also silhouette him.
CHAPTER 5. SUBMARINE ATTACK PLAN
3501. Upon sighting an enemy submarine, the boat making the contact should attack immediately, signalling his intentions to division commander or other nearby boats by gunfire, flag signal or voice radio. The one important fact to remember is that the chances of destroying the submarine decreases as the square of the time between last sighting him and dropping depth charges.
3502. The general plan for attacking an enemy submarine is for the boat making contact, to attack immediately and for nearby boats to follow up the attack, using the first boat's depth charges as a guide. First boat should signal direction of movement of submarine if known.
3503. The following general attack rules apply:
(a) When range is less than 1,000 yards, use 100 foot settings, when greater, use 200 foot settings. (Depth of water permitting.)
(b) When angle on the bow of submarine is less than 30° or greater than 150°, run down submarine track in making attack. When between 30° and 150° take a course leading the submarine's last sighted bearing by 15° and lay barrage across his track.
(c) Estimate range to submarine when last sighted and run on time to dropping point.
(b) Best attack speed is 36 knots. (100 yards in 5 seconds.)
(e) Slow to 20 knots when dropping.
CHAPTER 6. DEFENSE AND ESCAPE TACTICS-SMOKE
SCREENS
3901. Avoiding detection.-The subject of avoiding detection has already been covered in part 1 of this publication. Once detected, motor torpedo boats must maneuver at high speeds, using smoke or any other means available, to successfully carry out their mission and avoid enemy gunfire or bombs.
3902 (a). Attack on, and defense from enemy surface vessels.-During daylight torpedo attacks, when sighted and fired
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FIGURE 20.
NOTE.-(a) 1 sights sub at S and attacks with two barrages (8 charges).
(b) 2 attacks next with one barrage (4 charges).
(c) 3 attacks after 2's first barrage with about 6 charges.
(d) 2 and 3 lay remainder of charges if sub broaches or other evidence indicates his presence.
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upon by enemy surface vessels, a dispersion of boats should be made in order to present a multiplicity of targets. For example, if the division is in a normal deployment formation, boats should spread to about 300-500 yards distance, maintaining, if practicable, the same bearing on the leader. Attack plans should provide for a dispersion of divisions if several divisions are used in an attack, so the attack will be conducted with divisions approaching from different directions. This not only presents the enemy with smaller targets but gives him a greater number, thus rendering a difficult fire control problem. If the enemy uses barrage fire from guns larger than machine guns, zigzagging on the approach may be necessary with reasonable long and irregular runs to right and left of the base torpedo course. When within machine gun range, short zigzag courses should be used. Unless the enemy's fire is extremely accurate and salvos are falling close, zigzagging should not be resorted to as it slows down the approach considerably and increases the time in reaching the firing point thus permitting the enemy more time in solving the fire control problem. Each individual boat commander will be the best judge as to when it is necessary to zigzag to avoid destruction.
3902 (b). Normal retirement and escape.-Upon completion of the torpedo attack, opportunities may be had to continue closing the range and attack with machine guns, hand grenades or depth charges. In any case after completion of all attacks made by the division deployed in the normal manner, all boats should escape directly away from the enemy on divergent courses, covering the escape with smoke. The retirements should be made by vessels turning away from the center of the formation. In case of a three boat division, the center boat may turn either way.
3903. Defense from enemy aircraft-scatter plan.-The best defense against large numbers of enemy aircraft, when the enemy has definite air superiority, is not to have MTB's exposed to attack during daylight. Motor torpedo boats on such occasions should be well scattered and hidden and likewise their repair facilities and spare parts. However, if the division (while underway) is suddenly attacked by a small number of enemy aircraft (two or three) generally the best defense is to proceed at maximum speed and scatter in the V formation, with about 300-500 yards between boats. This gives the maximum mutual support to each other. A heavy volume of gun fire
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FIGURE 21.
FIGURE 22.
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should be brought to bear when the aircraft are within gun range: Defense tactics employed, will to a large degree, depend ups, the type of aircraft attacking. The following maneuvers will probably be most effective against the attacks as indicated:
(a) Attacked by dive bombers-attempt to turn under them using maximum speed.
(b) Attacked by horizontal bombers-90° changes of course at, high speed.
(c) Straffing attacks-use high speeds running across and slightly toward their line of attack. Avoid being raked from ahead or astern.
FIGURE 23.
During hazy or cloudy weather conditions, MTB's may often conceal themselves from aircraft by stopping and lying to. The wakes made by motor torpedo boats are normally more readily detected from the air or surface than the boats themselves.
If MTB's are attacked by large numbers of enemy aircraft, they should scatter in the normal manner and conceal themselves with smoke. (See art. 3904, example No. 3.)
High altitude bombing attacks on MTB's will probably not
be attempted or if they are they will undoubtedly be ineffective.
3904. Smoke screens.-The most difficult, and yet very often
the most effective, means of defense of motor torpedo boats is
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the use of smoke screens. Smoke might be used effectively by motor torpedo boats under the following conditions.
(a) In making an approach for delivery of a long range daylight torpedo attack on surface craft and in retiring from such attack.
( b) In escaping after delivery of a short range torpedo attack at night when illuminated and being fired upon by enemy screening or other vessels.
(c) As a protection when being attacked by aircraft or pursued by enemy light forces.
(d) Under special circumstances to screen the movements of other vessels.
In view of the fact that the effective use of smoke depends greatly on the existing tactical situation, the weather conditions (particularly the force and direction of wind), and the disposition of own and enemy forces, it will normally not be used under conditions (a) and ( b) above, unless directed. Smoke, when used improperly often proves to be a "boomerang" and aids the enemy while hindering own forces. Since the amount of smoke carried by motor torpedo boats is very limited, it should only be used when absolutely essential; for example, when speed and maneuverability are not sufficient to evade gunfire barrages, aircraft attacks, or to escape from surface craft.
Furthermore, if smoke screens are to be used, one boat should lay smoke for a division whenever possible in order to save smoke. In case of massed squadron attacks, one boat or one division might be able to lay smoke for a squadron under certain conditions.
The following examples are given wherein smoke might be effectively employed:
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EXAMPLE No. 1
1. MTB's to deliver a torpedo attack on armed enemy surface vessels during daylight high visibility, unsupported by own surface craft. Initial position, course and speed of enemy has been given.
(a) If possible the MTB's should select a course to intercept the enemy well forward of the enemy's beam (angle on the bow between 300-60°) and so that on the approach to attack the wind will blow the screen toward the enemy. (See diagram below.)
FIGURE 24.
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EXAMPLE No. 2
2. At night MTB's in units of one or more attack enemy surface vessels with torpedoes and in escaping are illuminated and fired upon. (See diagram below.)
FIGURE 25.
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EXAMPLE No. 3
3. While on patrol or other assigned operations, MTB's undergo repeated attacks by enemy aircraft and sustain or are likely to sustain severe damage. Under the above conditions it is desirable to lay a screen as rapidly as possible which will spread and permit the MTB to hide in the screen. If several vessels are to seek refuge in the same screen it is best to lay it over a larger area in an "S" or figure "8". When only a small area is covered, aircraft may drop fragmentation bombs using center of smoke as a point of aim and thus inflict possible damage. If only one boat is involved, a screen laid in a letter "0" or "G" would probably offer the most rapid solution. (See diagram below.)
FIGURE 26.
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EXAMPLE No. 4
4. MTB is being pursued and fired upon by a destroyer.
(a) If possible in escaping select a course going with the
wind, lay smoke.
(b) Use zigzag courses only as necessary to hide boat
and wake. ( See diagram below.)
