Note: Characteristics given are for warshot torpedoes. Weights indicated for these torpedoes include warhead fuel, etc.

The Howell Torpedo was named for its inventor, U.S. Navy LCDR John A. Howell. (He later became a Rear Admiral.) This torpedo was the only U.S. torpedo of its era (circa 1880) to attain enough success to be produced in quantity. The power for the Howell was received from a flywheel prespun before launch. In 1889, the U.S. Navy ordered 50 Howell Torpedoes from the Hotchkiss Ordnance Co., Providence, R.I., who had purchased the rights to the torpedo from Howell. This torpedo was used as an antisurface ship, battleship- and torpedo boat-launched weapon until 1898 when it was supplanted by the Whitehead Torpedo. An actual photograph of the Howell is shown on page 17.

Early accounts indicate that there were two versions of the Whitehead Torpedo Mk 1: a 3.55-meter (140-inch) version and a 5-meter (197-inch) version. The longer Mk I carried nearly twice the explosive charge (220 pounds) of the short version and was fitted with the Obry steering gear (gyro control in azimuth). The Whitehead Mk 1 (both lengths) was a "cold" running torpedo; the three-cylinder reciprocating engine ran on cold, compressed air which was stored in a section of the torpedo called the air flask. The E. W. Bliss Co., Brooklyn, N.Y., was the manufacturer of this torpedo for the U.S. Navy. It was used as an antisurface ship, battleship- and torpedo boat-launched weapon.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

Whitehead Torpedo Mk 1 (3.55 meter)

Whitehead Torpedo Mk 1 (5 meter)

There were two versions of the antisurface ship Whitehead Torpedo Mk 2; one was 3.55 meters (140 inches) in length while the second was 5 meters (197 inches) long. Both versions were 45 centimeters (17.7 inches) in diameter. The 5-meter Mk 2 had twice the range of the 3.55-meter Mk 2 (1500 yards versus 800 yards) and had a 10-percent increase in explosive charge (132 pounds versus 118 pounds). The 5-meter Mk 2 was probably based on the 5-meter Mk 1 rather than being a modification of the 3.55-meter Mk 2. This latter torpedo was identical to the 3.55-meter Mk 1 except for mechanical details. For the 5-meter Mk 2 within the 5-meter Mk 1 envelope, the capacity of the air flask was increased by 20 percent and the air flask pressure was increased from 1350 psi to 1500 psi. The launch platforms were battleships and torpedo boats.

Whitehead Torpedo Mk 2 (3.55 meter)

Whitehead Torpedo Mk 2 (5 meter)

*War Nose Mk 1, Mk 2, and Mk 5 were used interchangeably.

Unlike Whitehead Torpedoes Mk 1 and Mk 2, there was only one version of the Whitehead Mk 3 torpedo, the 3.55-meter. The main difference between the 3.55-meter Whitehead Mk 3 and the previous versions of this length was the inclusion of the Obry steering gear (gyro) for azimuth control. According to U.S. Navy acceptance tests for the Whitehead type torpedo, the maximum deviation right or left of the target was reduced from 24 to 8 yards in the Whitehead Mk 3. About 100 Torpedoes Mk 3 were purchased from the E. W. Bliss Co., and in 1913, redesignated Torpedo Type A. The Whitehead Torpedo Mk 3 was withdrawn from service use in 1922 when all torpedoes designed prior to Torpedo Mk 7, were condemned in favor of more modern weapons.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

After the E.W. Bliss Co. had manufactured Whitehead Torpedoes for several years, one of the company's engineers, F. Leavitt, developed a turbine-driven antisurface ship torpedo which was designated the Bliss-Leavitt Torpedo Mk 1. In addition to the engine change, the air flask pressure of the new weapon was increased to 2250 psi (vice 1500 psi for the Whitehead units). The air in the new model was heated by burning alcohol in a chamber upstream from the engine. The increased air flask pressure and heated air served to increase the range of the Bliss-Leavitt Mk 1 to 4000 yards at 27 knots. (The range was 1500 yards at 28.5 knots for the 5-meter Whitehead Mk 2.) This torpedo, in service on battleships, torpedo boats, and cruisers, used a single vertical turbine wheel rotating about the torpedo's longitudinal axis and driving a single propeller. The unbalanced torque was sufficient to cause the Mk 1 to have a tendency to roll.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

The Bliss-Leavitt Torpedo Mk 2 was a "hot running" (propelled by heated air), 21-inch (in diameter) torpedo used on battleships, torpedo boats, and cruisers. This antisurface ship torpedo, developed by the E.W. Bliss Co., Brooklyn, N.Y., was the first weapon to use two contrarotating turbines with each driving a propeller. The development eliminated the unbalanced torque which had contributed to the tendency of the Bliss-Leavitt Mk 1 to roll. About 250 units were manufactured by the E.W. Bliss Co. for the U.S. Navy.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

Developed and manufactured by the E.W. Bliss Co., Brooklyn, N.Y., the Bliss-Leavitt Torpedo Mk 3 was very similar to the Bliss-Leavitt Mk 2. This torpedo was a "hot running," 21-inch (in diameter) antisurface ship torpedo used on battleships, torpedo boats, and cruisers. The main difference between Mk 2 and Mk 3 was that the Mk 3 had an increased range (4000 yards versus 3500 yards for Mk 2). Approximately 200 Bliss-Leavitt Torpedoes Mk 3 were produced for the U.S. Navy.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

The Bliss-Leavitt Torpedo Mk 4, an 18-inch antisurface ship weapon, was the first torpedo specifically designed for submarine launching. (Earlier torpedoes were used on battleships and cruisers.) Developed and produced by the E.W. Bliss Co., about 100 of these units were purchased by the U.S. Navy for experimental purposes. The experiments with the Bliss-Leavitt Torpedo Mk 4 led to design improvements to the gyro and the reducing valve. In 1922, the torpedo and all other torpedoes designed prior to Torpedo Mk 7, were considered obsolete and withdrawn from service use.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

A "hot running" (powered by heated air) torpedo of Whitehead design, the Mk 5 torpedo was the first torpedo to be manufactured by the Naval Torpedo Station in Newport, R.I. (1908). The Mk 5 was similar in performance to the Bliss-Leavitt torpedoes of that era, and approximately 500 units were produced by the Torpedo Station and Vickers Ltd. of England. This torpedo was doomed, however, by a major technological advancement (increased efficiency and range) in the Bliss-Leavitt Torpedo Mk 7 which came soon after the Mk 5 was produced. The Mk 5 was the first to permit the firing ship to vary speed and range. The Mk 5 was accomplished by adjustment of the reducing valve prior to tube loading. The Mk 5 was used on battleships, torpedo boats, and submarines, and was an antisurface ship weapon.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

The Bliss-Leavitt Torpedo Mk 6 was an 18-inch antisurface ship torpedo designed for above-water tubes and could be launched from destroyers and cruisers. It featured a main engine that was a horizontal turbine rather than the vertical turbine used on all other Bliss-Leavitt torpedoes. The Mk 6 depth and gyro controls were also combined into one unit as another design change. Although the Mk 6 torpedo reached speeds up to 35 knots, its range was conversely reduced to 2000 yards. About 100 units were manufactured by the E.W. Bliss Co.

*War Noses Mk 1, Mk 2, and Mk 5 were used interchangeably.

Torpedo Mk 7, a submarine/destroyer-launched antisurface ship torpedo, was a major step forward in the evolution of the modern torpedo. It featured the introduction of water into the combustion pot to cool the combustion gases and produce steam. Propulsive efficiency was increased which, in turn, resulted in an increase in the range. Developed by the Bliss-Leavitt Co., Brooklyn, N.Y., and the Naval Torpedo Station, Newport, R.I., Torpedo Mk 7 was issued to the Fleet in 1912 and remained in service through World War II. This torpedo was also in development/experimentation as an aircraft-launched weapon in the early 1920s.

The Type D Torpedo was a shorter version of the Mk 7 torpedo. Developed by Washington Navy Yard, Washington, D.C., in order to fit certain submarine torpedo tubes, the Mk 7 air flask was shortened and the weight of the warhead was reduced. The fuel and water tanks were relocated to obtain more air flask capacity on the Type D. The fuel tank was mounted in the aft air flask bulkhead while the water tanks were mounted in the afterbody. The overall weight of the warshot torpedo, as compared to the Mk 7, was 590 pounds lighter and 58 inches shorter. In addition, air, fuel and water capacities were approximately one-third of the capacities found in the Mk 7 torpedo. This torpedo was never produced in quantity.

Developed during World War I, the Mk 8 was the U.S. Navy's first 21-inch by 21-foot torpedo. The Naval Torpedo Station at Newport, R.I., the Torpedo Station in Alexandria, Va., and the U.S.N. Gun Factory in Washington, D.C. were all involved in the production of this destroyer-launched, antisurface ship torpedo which was still in the inventory at the start of the second World War. Approximately 600 Mk 8 torpedoes were issued to Great Britain to use with 50 old-type U.S. destroyers turned over to England under the lend-lease act.

Developed around 1915 by the Naval Torpedo Station, Newport, R.I., and the E.W. Bliss Co., Brooklyn, N.Y., Torpedo Mk 9 was designed for use by battleships. Prior to issue, however, use of torpedoes on battleships was discontinued and Mk 9 torpedoes were placed in reserve (storage). Modified for use in R- and S-class submarines, this antisurface ship torpedo was used in early World War II to supplement the initial supply of Torpedoes Mk 14. Torpedo production for the U.S. Navy was terminated by the E.W. Bliss Co. about 1920 after completion of the Mk 9 project.

Torpedo Mk 10 was developed by the E.W. Bliss Co. and the Naval Torpedo Station, Newport, R.I., and produced in 1915 by the Torpedo Station, to be used as a fast, short-range, antisurface ship torpedo. The Mk 10 featured the largest payload (warhead of =500 pounds) of any torpedo developed up to that time. Used in R- and S-class submarines after World War I, this torpedo saw service in the early years of the second World War.

Developed by Washington Navy Yard, Washington, D.C., and the Naval Torpedo Station, Newport, R.I. the Mk 11 torpedo was a destroyer-launched, antisurface ship torpedo which had the first three-speed setting capability (selectable while tube loaded). The development was completed in 1926 and Torpedo Mk 11 became the first torpedo to be designed totally within the Navy (without industry collaboration). An objective was to attain a "universal" use torpedo (i.e., could be launched from any type of platform).

Similar in design to the Mk 11 torpedo (but with detail refinements), Torpedo Mk 12 was a destroyer-launched, antisurface ship torpedo. This torpedo had a lower high-power setting than the Mk 11 (44 versus 46 knots) to improve reliability. The development of this torpedo by the Naval Torpedo Station, Newport, R.I., was completed in 1928. Two hundred units were manufactured by the Torpedo Station.

Torpedo Mk 13 was the first torpedo designed specifically for aircraft launching. Developed by the Naval Torpedo Station, Newport, R.I., approximately 17,000 of these antisurface ship torpedoes were produced during World War II. Among the producers were the Naval Torpedo Station; Pontiac Motor Division, Pontiac, Mich.; the Amertorp Corp., Forest Park Ill., and St. Louis, Mo.; and the International Harvester Co. The Mk 13 torpedo saw service during the second World War and was eventually outmoded by ASW torpedoes.

Torpedo Mk 14, developed as a replacement for the Mk 10 torpedo had a longer range than the Mk 10 and had a 100-pound heavier warhead charge. This torpedo was the primary submarine-launched, antisurface ship torpedo used in World War II until the introduction of the electric Torpedo Mk 18. Approximately 4,000,000 tons of Japanese shipping were sunk by the Mk 14 torpedo. Originally introduced for use as mechanically-set torpedo, the Mk 14 was modified for use with modern fire control systems (and designated Mod 5). This torpedo is still in service use. Torpedo Mk 14 was developed by the Naval Torpedo Station, Newport, R.I. and approximately 13,000 were produced during the second World War by the Naval Torpedo Stations in Newport; Alexandria, Va.; and Keyport, Wash.; and the Naval Ordnance Plant, Forest Park, Ill.

Developed and produced by the Naval Torpedo Station, Newport, R.I., Torpedo Mk 15 was designed as a replacement for the Mk 11 and Mk 12 torpedoes in surface ship application. It was 17 inches longer and 300 pounds heavier than its predecessors. The additional weight was due to increased payload. Approximately 9700 Mk 15 torpedoes were produced during the period 1940 through 1944. This torpedo was the last destroyer-launched, antisurface ship torpedo in wide service use. As part of the Fleet modernization program of the 1950's, it was phased out of service by the removal of the quintuple-mount torpedo tubes from destroyers. Torpedo Mk 15 was developed by the Naval Torpedo Station, Newport, R.I., and produced by the Torpedo Station and by the Naval Ordnance Plant, Forest Park, Ill.

In 1943, the Naval Torpedo Station, Newport, R.I., and the Naval Research Laboratory, Washington, D.C., began development of a submarine-launched, antisurface ship torpedo designated Torpedo Mk 16. The decision to use "Navol" (concentrated hydrogen peroxide (H₂O₂O)) as an oxidant came as a result of research on chemical torpedoes which began in 1915. Torpedo Mk 16, which was also produced at the Torpedo Station in Newport, and at the Naval Ordnance Plant, Forest Park, Ill., had the same physical characteristics as the Mk 14 Mod 3 torpedo. As a result of World War II, production began before development was completed on this torpedo. None of the Mk 16 torpedoes were used in combat, although 60 units were completed prior to the end of the war. Production continued in post-World War II years, however, with over 1700 Torpedoes Mk 16 manufactured. The final version was Torpedo Mk 16 Mod 8 which was withdrawn from service use in 1975.

Development on Torpedo Mk 17 began in 1940 by the Naval Torpedo Station, Newport, R.I., and the Naval Research Laboratory, Washington, D.C. A long-range, high-speed torpedo, the Mk 17 was a destroyer-launched, antisurface ship weapon using "Navol" (concentrated hydrogen peroxide (H₂O₂O)) as an oxidant. Torpedo Mk 17 development, halted in 1941 due to pressure to produce Torpedoes Mk 13 and Mk 15 for the war effort, was resumed again in 1944. (Detailed knowledge of the Japanese type 93 "Long Lance," a 22,000-yard, 49-knot oxygen torpedo became available about this time.) As in the case of the Mk 16 torpedo, the Mk 17 went into production before development was completed. The producer was the Torpedo Station in Newport. Although there were 450 Mk 17 torpedoes completed before the end of the second World War, none were used in combat. Torpedo Mk 17 was discontinued around 1950 after seeing only limited use in post-war years. Main factors in the early demise of the Mk 17 were its contribution to destroyer topside weight, similarity to the Mk 16, and, also, the emerging role of destroyer as an antisubmarine warfare platform.

Torpedo Mk 18, a submarine-launched, antisurface ship weapon, was one of the most successful torpedoes of World War II. This torpedo, based on a captured G7e German torpedo, was widely used in the latter stages of the war. Torpedo Mk 18 was developed by the Westinghouse Electric Corp., Sharon, Pa., and the Electric Storage Battery Co., Philadelphia, Pa., and approximately 9000 were produced by Westinghouse and the Naval Ordnance Plant, Forest Park, Ill. In 1944, 30 percent of the torpedoes fired from submarines were Mk 18 torpedoes, while in 1945, it was 65 percent. The tactical advantage of Torpedo Mk 18 was the lack of a wake. About 1,000,000 tons of Japanese shipping were sunk by the Mk 18 torpedo.

Torpedo Mk 19 was a follow-on development of the Mk 18 torpedo, designed to incorporate all-electric controls in lieu of pneumatic controls. The Mk 19, an antisurface ship torpedo, which was developed by the Westinghouse Electric Corp., Sharon, Pa., was designed to be submarine launched. The propulsion power was supplied by a direct current, series-wound motor which received its energy from a secondary storage battery. The gyroscope and depth control were electrically controlled and operated; the rudders were solenoid operated. Ten prototypes were built, but further development was cancelled in favor of Torpedo Mk 26.

Torpedo Mk 20 was actually the 1943 designation for the continuation of the development of a submarine-launched, antisurface ship torpedo originally designated Mk 2 (in 1941). The torpedo was developed by the Naval Torpedo Station, Newport, R.I.; the Electric Storage Battery Co., Philadelphia, Pa.; and the General Electric Co., Pittsfield, Mass. This was the second attempt to develop a torpedo of this type. Earlier efforts (Mk 1) in post-World War I years (1919-1931) were terminated due to unsatisfactory speed/range performance. Torpedo Mk 20 never progressed beyond the development stage due to the success of the Mk 18 torpedo. However, 20 units were produced by the General Electric Co., Bridgeport, Conn., for testing.

Torpedo Mk 21 Mod 0, an antisurface ship, aircraft-launched, passive acoustic homing torpedo was developed by the Westinghouse Electric Corp., Sharon, Pa. During the same time period, the Harvard Underwater Sound Laboratory, Harvard University; and the Bell Telephone Laboratories, Murray Hills, N.J., were adapting Torpedo Mk 13 for acoustic control. The Mk 21 Mod 0 torpedo successfully passed launching tests late in 1943. Because of the increasing difficulties encountered by the developer, the Torpedo Mk 21 Mod 0 project was abandoned after only a few development models had been built.

Torpedo Mk 21 Mod 2 was a passive homing version of the Mk 13 torpedo intended for use as a payload for the Petrel guided missile. An aircraft launched, antisurface ship weapon, it was developed as a joint effort by the Bell Telephone Laboratories, Murray Hill, N.J.; the Harvard Underwater Sound Laboratory, Harvard University; and later, the Ordnance Research Laboratory, Pennsylvania State University. The Naval Ordnance Plant, Forest Park, Ill., produced a limited quantity (312) during 1946 through 1955. Development was discontinued and this torpedo was not used in service to any appreciable degree.

Developed by the Bell Telephone Laboratories, Murray Hill, N.J.; and Westinghouse Electric Corp., Sharon, Pa., Torpedo Mk 22 was the World War II development of an antisurface ship, submarine-launched torpedo. It had active acoustic terminal homing in azimuth only, probably in an attempt to reduce boundary (surface/bottom) capture problems. Further development on this torpedo was discontinued after the BuOrd evaluation stage, which coincided with the end of the second World War. The decision to continue with the development of Torpedo Mk 35 during the post-war years was the probable cause for the discontinuation of Mk 22 work.

Torpedo Mk 23 was developed to satisfy what appeared to be a valid tactical requirement of World War II: the high-speed feature of the Mk 14 torpedo. In the early stages of the war, the low-speed feature (31 knots - 9000 yards) of the Mk 14 was rarely used. Due to the changing requirements of the war, however, most of the 9600 Mk 23 torpedoes saw little service. In the latter stages of the second World War, fewer targets and better/smarter escorts/escort tactics necessitated firing from longer ranges. The Mk 14 torpedo, with its low power and longer range, became the preferred weapon. Much of the Mk 23 inventory was scrapped or converted to Torpedoes Mk 14 while other units were cannibalized for spare parts. This submarine-launched, antisurface ship torpedo was developed by the Naval Torpedo Station, Newport, R.I., and produced by the Naval Torpedo Stations at Newport; Alexandria, Va.; and Keyport, Wash.; and by the Naval Ordnance Plant, St. Louis, Mo.

Called a mine for security reasons, the Mk 24 was developed as an outgrowth of work on an underwater listening device sponsored by the Naval Defense Research Committee during World War II. This torpedo, with a small warhead, was a crippling weapon designed for "mission kill" vice "platform kill." Approximately 4000 of these aircraft-launched, passive acoustic, antisubmarine torpedoes were produced and in service during World War II and subsequent years until replaced by Torpedo Mk 34. Mine Mk 24 was developed by a group of activities including Western Electric Co., Kearney, N.J.; Bell Telephone Laboratories, Murray Hill, N.J.; Harvard University Underwater Sound Laboratory, Cambridge, Mass.; and General Electric Col Schenectady, N.Y. The Western Electric Co., Kearney, N.J., and General Electric Co. in Erie and Philadelphia, Pa. were the producers.

Sponsored by the National Defense Research Committee, Torpedo Mk 25 was developed by Columbia University, Division of War Research, as a replacement for Torpedo Mk 13. The new torpedo was an aircraft-launched, antisurface ship weapon designed for higher speed, greater strength and more ease of manufacture than the Mk 13 torpedo. Torpedo Mk 25 had thermal propulsion, was turbine driven and obtained a speed of 40 knots and a range of 2500 yards. Twenty-five units were produced by the Naval Ordnance Plant, Forest Park, Ill., during 1946 for test and evaluation. This torpedo was never mass-produced, however, due to the large inventory of Mk 13 torpedoes left at the end of World War II, and the changing role of Naval aircraft from a torpedo strike warfare platform to an antisubmarine warfare platform.

Torpedo Mk 26, an improved version of the Mk 28, was developed by the Westinghouse Electric Corp. as an antisurface ship, submarine-fired weapon. This torpedo introduced a primary (seawater) battery developed by Bell Telephone which provided high performance. The Mk 26 torpedo was also the first torpedo to use an explosive impulse start gyro and electric "on-off" control for steering and depth control. Approximately 25 developmental models were built by Westinghouse, but production was deferred in favor of the Mk 16 torpedo.

Torpedo Mk 27 Mod 0, developed by Bell Telephone Laboratories, was an acoustically-controlled, submarine-launched, anti-escort ship weapon. Used during the second World War, the torpedo had a single propeller driven by an electric motor. This torpedo was essentially a Mine Mk 24 modified for submarine launching in a 21-inch submerged torpedo tube by the addition of wood guides on the outer cylinder shell. Approximately 1000 units were produced by the Western Electric Corp., Kearney, N.J.

Developed by the Ordnance Research Laboratory Pennsylvania State University, Torpedo Mk 27 Mod 4 was an improved version of the Mk 27 Mod 0. This torpedo was an anti-escort torpedo, fully compatible with electrical setting fire control systems through the incorporation of the standard 65-pin umbilical cable. Approximately 3000 of these torpedoes were produced by the American Kitchens Div. of the AVCO Corp., Connersville, Ind.; and the Naval Ordnance Plant, Forest Park, Ill., from 1946 through 1954. In service in submarines for about ten years, Torpedo Mk 27 Mod 4 was withdrawn from service use in 1960 with the introduction of Torpedo Mk 37.

Developed and produced late in World War II by the Westinghouse Electric Corp., Sharon, Pa., Torpedo Mk 28 was an antisurface ship, submarine-launched, acoustic homing torpedo with a medium explosive charge. The torpedo also incorporated all-electric controls. Approximately 1750 torpedoes were produced during the period from 1944 to 1952 but in-service use ceased after the introduction of Torpedo Mk 37.

Torpedo Mk 29 Mod 0 was an antisurface, submarine-launched, passive acoustic torpedo. This torpedo, developed by the Westinghouse Electric Corp., Sharon, Pa., used the same acoustic system as Torpedo Mk 28. Torpedo Mk 29 Mod 0 differed significantly from the Mk 28 in other ways, however. The newer torpedo was faster, operated at various depths, had an external depth setter, and ran as either a straight or a homing torpedo. Torpedo Mk 29 Mod 1, developed during the same time period, had two speeds, a remote-setting variable enabler and an anticircular run device. In the Mod 1, the electric motor on the impulse start gyro was replaced by a cartridge-start impeller motor to obtain a longer gyro controlling time. In April 1945, the Mk 29 program was discontinued after BuOrd evaluation, due to the fiscal constraints of the peacetime economy and planned developments.

Optical wake sensing devices developed in Australia were the basis of Torpedo Mk 30 development by the Naval Ordnance Laboratory, Washington, D.C. The Mk 30 was a destroyer/submarine-launched, antisurface ship, homing torpedo that used the wake of a target ship to operate the steering mechanism. Torpedoes Mk 18 and Mk 14 were used as test vehicles for the detector heads and control units of this wake following system. The test program for this torpedo was transferred from the Naval Mine Warfare Test Station in Solomon, Md., to the Ordnance Research Laboratory at Pennsylvania State University in 1946. Subsequently, the program was abandoned as a complete torpedo development. It was, however, continued as a study of a system for homing control.

Mine Mk 30, an aircraft-launched, antisubmarine torpedo, was developed by the Brush Development Co., Cleveland, Ohio, during 1942 and early 1943. It was designed in parallel with and as a backup for Mine Mk 24 because, at that time, there was apprehension about the Mine Mk 24 acoustic steering. Mine Mk 30 was unique because of its size; it was 10 inches in diameter, 98 inches long, and weighed 265 pounds. (Fifty pounds of the total weight was the explosive charge.) Three prototype Mines Mk 30 were manufactured and tested in January of 1943 and satisfactory performance was indicated. No production of Mine Mk 30 was initiated, however, because of the successful acoustic steering of an aircraft-launched Mine Mk 24 in late 1942.

Torpedo Mk 31 Mod 1, an acoustically-steered modification of the Mk 18 electric torpedo, was conceived as a readily producible interim weapon to be used in the Pacific until an entirely new high-speed acoustic torpedo could be developed. The Mk 31, developed by the Harvard Underwater Sound Laboratory, and the Ordnance Research Laboratory, was a destroyer-launched, antisurface ship torpedo. Although some units of the Mk 31 torpedo were produced by the Naval Torpedo Station, Newport, R.I., further development of the torpedo was stopped after BuOrd evaluation due to the status of other development programs (Torpedoes Mk 16 and Mk 35).

Torpedo Mk 32 Mod 2 was a surface ship-launched, antisubmarine torpedo featuring active acoustic homing. An end product of World War II acoustic homing system development, it was the first active acoustic torpedo. Developed by a combined effort between the General Electric Co., Schenectady, N.Y., and the Ordnance Reserach Laboratory, Pennsylvania State University, for aircraft launching, this torpedo saw limited use in destroyers with the Mk 2 over-the-side launchers for a number of years. A few (10) torpedoes of this type were produced by Leeds and Northrup, Philadelphia, Pa., during the second World War and approximately 3300 in post-war years by the Philco Corp., Philadelphia, and the Naval Ordnance Plant, Forest Park, Ill. Torpedo Mk 32 was withdrawn from service use with the introduction of the Mk 43 torpedo.

Torpedo Mk 33 was a two-speed, passive acoustic homing, antisurface ship/ antisubmarine torpedo designed to be launched from a standard submarine torpedo tube or aircraft. Developed by the Bureau of Ordnance, the General Electric Co., and the Exide Co., this torpedo had a hydraulic steering system and had the first cast aluminum shell. Only 30 models of the Mk 33 torpedo were constructed and tested between 1943 and 1946. Production was discontinued when World War II ended but Torpedo Mk 33 features were incorporated into the Mk 35 torpedo.

Torpedo Mk 34 Mod 1 (initially designated Mine Mk 44), an improved version of Mine Mk 24, used magnetrostrictive hydrophones in lieu of crystal hydrophones. It also used two propulsion batteries in a parallel/series switching arrangement which provided for longer search time/range and a shift to higher speed during attack after acquisition. Developed by the U.S. Mine Warfare Test Station, Solomons, Md., approximately 4050 were produced during the period from 1948 through 1954. The main producers of this torpedo were the American Machine and Foundry Co., Buffalo, N.Y.; the Naval Ordnance Plant, Forest Park, Ill.; and the Naval Mine Depot, Yorktown, Va. In-service in ASW aircraft for many years, this torpedo was withdrawn from Fleet use with the introduction of Torpedo Mk 43.

Developed in 1944 by the General Electric Co., Torpedo Mk 35 was an outgrowth of work done on Mine Mk 24, and Torpedoes Mk 32 and Mk 33. This torpedo, intended as a "universal" torpedo (i.e., could be launched from any type of platform), was a surface ship-launched, antisurface ship weapon featuring deep diving and long range homing. Approximately 400 Mk 35 torpedoes were manufactured by G.E. Co., Aeronautical and Ordnance Systems Div., Pittsfield, Mass., during the period from 1949 through 1952. After having seen only limited service, Torpedo Mk 35 was withdrawn from Fleet use around 1960 as a result of the introduction of Torpedo Mk 37.

The ultimate objective of the Torpedo Mk 36 development program was the design of an accurate, wakeless, pattern-running underwater missile having the highest possible speed consistent with long range. Originally designed in early 1944 under an amended Mk 20 contract, Torpedo Mk 36 was an all-electric, submarine-launched, antisurface ship torpedo employing a motor of approximately 350 horsepower and a seawater-type primary battery. The General Electric Co., Pittsfield, Mass., and the Naval Torpedo Station, Newport, R.I., were responsible for its design. Between 1946 and 1950, further development of the Mk 36 torpedo was discontinued due to the development of Torpedo Mk 42.

Torpedo Mk 37 is a two-speed, electrically-driven, active/passive acoustic homing torpedo. The main developers of the Mk 37 were Westinghouse Electric Corp., Sharon, Pa.; the Harvard Underwater Sound Laboratory, Cambridge, Mass.; and the Ordnance Research Laboratory of Pennsylvania State University. Engineering development of Torpedo Mk 37 began in 1946 but work had started in 1942 on the Project 4 panel (an echo-ranging, Doppler-enabled, acoustic homing system), which was incorporated into the Mk 37. The Mk 37 torpedo was produced in quantity by the Naval Ordnance Plant, Forest Park, Ill., and was the standard U.S. Navy submarine-launched, antisubmarine weapon for about 20 years. All Torpedoes Mk 37 Mod 0 have been withdrawn from the Fleet, refurbished, updated, and reissued to the Fleet as the Mod 3. Since the Mk 37 torpedo is available for foreign countries under the Military Assistance Program, however, some countries still maintain the Mod 0 version.

Torpedo Mk 37 (Mods 1 and 2) was a follow-on development of Torpedo Mk 37 Mod 0. This submarine-launched, antisubmarine weapon was developed by the Naval Underwater Ordnance Station, Newport, R.I., and the Vitro Co., Silver Springs, Md. The principal modification to the Mod 0 was the addition of a wire guidance capability. This wire guidance feature lengthened the torpedo by 26 inches and increased the weight by 260 pounds. In addition to the change to the torpedo, submarine fire control systems and torpedo tubes were also modified to provide the wire guidance capability. Torpedoes Mk 37 Mod 1, manufactured by the Naval Ordnance Plant, Forest Park, Ill., were refurbished and reissued to the Fleet as Mk 37 Mod 2 torpedoes. Under the Military Assistance Program, the Mod 1 version has been sold to foreign governments; only the Mod 2 version is still in use by the U.S. Navy.

Torpedo Mk 38 was the designation given to a planned post-World War II antisurface ship, submarine-launched, acoustic homing torpedo intended to replace the Mk 28 torpedo. This development was postponed pending development and evaluation of Torpedo Mk 37. With the success of the Mk 37, development and subsequent evaluation plans for the Mk 38 were terminated.

Torpedo Mk 39 Mod 1, developed by the Vitro Corp., Silver Springs, Md., and the Ordnance Research Laboratory at Pennsylvania State University, was the first torpedo to employ a trailing wire for mid-course guidance through the submarine fire control system. This torpedo was actually a Torpedo Mk 27 Mod 4 converted by the Philco Corp., Philadelphia, Pa., for Fleet familiarization and development of wire guidance techniques. The wire guidance feature was eventually incorporated into Torpedoes Mk 37 Mod 1 and Mk 45 which were issued for Fleet use. Because of this incorporation of wire guidance into other torpedoes, the Mk 39 submarine-launched, antisubmarine torpedo was considered obsolete and remaining units were scrapped.

Torpedo Mk 40 was the designation given to a proposed 1000-pound, aircraft- or guided missile-launched, antisurface ship torpedo, with a hydro-turbo jet or pump jet propulsion system. Work on this project confirmed German demonstrations that multibase solid propellants may be utilized to provide a gas supply (for short periods of time) at the pressures and temperatures found desirable for the application in question. The Torpedo Mk 40 developed by the Naval Ordnance Test Station, Pasadena, Calif., was discontinued due to technology limitations and to the emergence of Naval aircraft as an ASW platform rather than as a strike warfare torpedo platform.

Developed by the General Electric Co., Pittsfield Mass., as the antisubmarine, aircraft-launched version of the Torpedo Mk 35, the Mk 41 Mod 0 torpedo utilized the same homing system and the same type of propulsion as the Mk 35. The main difference between the Mk 35 and the Mk 41 was that functions unnecessary for aircraft launch were eliminated from the Mk 41. The Mk 41 unit was also made as compact as possible. Approximately 200 units were produced by G.E. for evaluation but production was discontinued in favor of the Mk 43 type torpedo.

The Mk 42 torpedo was intended to be a submarine-launched, pattern-running, antisurface ship torpedo. In this development, an attempt was made to consolidate into one weapon past experience on the development of various torpedo components. Contributing to the development were the Naval Ordnance Test Station, Pasadena, Calif.; the Naval Ordnance Laboratory, Washington, D.C.; the Naval Torpedo Station, Newport, R.I.; the Ordnance Research Laboratory, Pennsylvania State University; and Stevens Institute of Technology, Hoboken, N.J. Torpedo Mk 42 development was terminated in 1952 with the intent of developing a pattern-running mod of Torpedo Mk 16.

Torpedo Mk 43 Mod 0 was an aircraft-launched ASW torpedo. It was developed and produced by the General Electric Co., Pittsfield, Mass., to provide a lightweight, inexpensive torpedo for ASW use from fixed- and rotary-wing aircraft and airships. Approximately 500 of these torpedoes were manufactured for evaluation purposes but were discontinued in favor of Torpedo

Mod 1

Mod 3

Torpedo Mk 43 Mods 1 and 3 were developed by Brush Development Co., Cleveland, Ohio, and the Naval Ordnance Test Station, Pasadena, Calif., during the post-World War II years. This was the first lightweight, antisubmarine torpedo capable of being launched by helicopters, fixed-wing aircraft, and surface ships. Approximately 5000 of these torpedoes were produced by the Brush Electronics Co., Cleveland, Ohio, and the Naval Ordnance Plant, Forest Park, Ill., from 1951 through 1959. This torpedo was withdrawn from Fleet use after the introduction of the Mk 44 torpedo.

Torpedo Mk 44 was a second-generation, lightweight ASW torpedo and the first service torpedo with a seawater-activated battery as a power source. This torpedo, the replacement for Torpedo Mk 43, had improvements in speed, warhead size, acoustic homing capabilities, and prelaunch-selectable search parameters. The Mk 44 was developed by the Naval Ordnance Test Station, Pasadena, Calif., and the Aeronautical and Ordnance Systems Division of the General Electric Co., Pittsfield, Mass. Production was started in 1957 at G.E., and in succeeding years at the Naval Ordnance Plant, Forest Park, Ill., and at the American Machine and Foundry Co., Buffalo, N.Y. Torpedo Mk 44 was used in service on U.S. destroyers and aircraft as an ASW weapon for about ten years until it was replaced by Torpedo Mk 46. In addition to being purchased by foreign governments under the Military Assistance Program, the Mk 44 torpedo was produced in Europe by NATO countries.

Torpedo Mk 45 was a submarine-launched, antisubmarine, antisurface ship torpedo with wire guidance capabilities and a nuclear warhead. Using a seawater-activated battery as a power source, the torpedo was capable of high-3peed, long-range, and deep-depth operation. Developed by the Applied Research Laboratory, University of Washington, Seattle, Wash., and the Westinghouse Electric Corp., Baltimore, Md., the Mk 45 torpedo was produced by Westinghouse starting in 1959. This torpedo, which was restricted to U.S. Navy use only, was phased out of service when Torpedo Mk 48 became available.

Developed by the Naval Ordnance Test Station, Pasadena, Calif., and Aerojet General, Azusa, Calif., the Mk 46 torpedo is a third-generation, lightweight ASW weapon. It is powered by a thermal piston engine and is capable of higher speed, longer range, better acoustic performance, and deeper depth operation than its predecessors. (Torpedo Mk 46 Mod 0 uses a solid propellant grain while the Mod 1 uses liquid monopropellant fuel. The Mod 1 performance in speed and range is better.) Torpedo Mk 46 production began at Aerojet General in 1963 and in the next two years production commenced at the Naval Ordnance Plant, Forest Park, Ill., and at Minneapolis Honeywell Inc., Hopkins, Minn. The Mk 46 torpedo is currently in service on U.S. Navy destroyers and aircraft and has been purchased by foreign governments under the Military Assistance Program. The torpedo will continue in service until replaced by a new generation lightweight ASW torpedo.

Torpedo Mk 47 was the designation given a proposed antisurface, submarine-launched, high-speed torpedo. This torpedo was to have either thermal or electric propulsion. The development program was terminated before characteristics for the Mk 47 were fully defined due to the status of Torpedo

Torpedo Mk 48 is a long-range, high-speed, deep-depth, wire-guided, acoustic homing weapon used for detecting and attacking surface ships and fast, deep-diving submarines. The development of Torpedo Mk 48 Mod 0 grew out of the Navy's in-house Research Torpedo Configuration Program in 1963. Developed by the Applied Research Laboratory, Pennsylvania State University, and the Westinghouse Electric Corp., Baltimore, Md. (the prime contractor), this mod employed a turbine propulsion system. The end product of this development was redesignated Torpedo Mk 48 Mod 2. In 1967 Gould, Inc., Cleveland, Ohio (the prime contractor), and the Naval Surface Warfare Center, White Oak, Md., began developing Torpedo Mk 48 Mod 1. This version had a substantially redesigned acoustic homing system, and a piston engine was used for propulsion. After both the Mod 1 and Mod 2 Mk 48 torpedoes were evaluated, the Torpedo Mk 48 Mod 1 was selected for production at Gould, Inc., for ultimate Fleet use.

The ASROC Missile is a solid fuel, rocket-propelled ballistic missile designed for standoff delivery from surface ships against submerged submarines. There are two basic missile configurations: (1) a rocket-thrown torpedo employing an acoustic homing torpedo as a payload, and (2) a rocket-thrown depth charge. In the torpedo configuration, the missile components are separated from the torpedo in flight and from that point, the torpedo enters the water and functions as though it was launched from an aircraft. The ASROC Missile is operational aboard cruisers, destroyers, and escort ships of the U.S. Navy. This missile was developed by the Naval Ordnance Test Station, Pasadena, Calif., and the Minneapolis Honeywell Regulator Co., Hopkins, Minn. There are many manufacturers of the ASROC since it is produced as individual components rather than as a complete unit. The components are then assembled into missiles by each issuing Navy activity.

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