Torpedoes & Equipment

    Originally, Destroyer Escorts were equipped with a triple bank of 21" torpedo tubes. Later improvements to the AA armament required grounding the torpedo tubes in favor of additional 20mm or 40mm guns. For the DEs supplied under lend-lease, the British elected replace the torpedo bank with either 40mm Cannons or 20mm machine guns to defend against air attack.  In hindsight, they were correct. There are only two recorded instances of DEs attacking enemy targets with the torpedoes, and both were failures. This is a triple-tube launcher firing a Mark 15 torpedo.

National Archives #80-G-462565

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    The torpedoes are ejected from their tubes by a black powder charge, much like the K-gun. As the torpedo left the tube, a lever activated the torpedo motor, usually steam that was generated by mixing alcohol and kerosene. The operator sat on top of the mount on a small bench and operated the entire mechanism. (Close-up photos of the controls are below.) The photo shows a Mark 15 torpedo launching. Notice the steam exhaust near the twin propellers.

National Archives #80-G-462566

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Mk 15 Surface-Launched Anti-Surface Torpedo  

    The Mark 15, developed in 1935 (from a 1918 Mark 11 design) and added to the fleet in 1938. This $10,000 torpedo was similar to the improved Mark 14, it was equipped with a conventional contact exploder and was one of the last steam-driven weapons.  It was slightly longer, heavier, carried a larger payload, and had a three-speed capability. It was the last torpedo designed to be launched from destroyers against surface ships. 

    The Mk-15 was the standard Destroyer Escort mounted torpedo.  It was carried on all classes of U.S. Destroyer Escorts but was not installed on the Buckleys transferred to England under the Lend Lease agreement.  The Mk 15 was the surface-launched model of the torpedo-trio (Mk-13/-14/-15), sharing many of the family's defects.

    The Mk-15 was developed from 1936 onwards and was in wide-spread service by 1941. There are no recorded instances of Destroyer Escorts employing torpedoes to sink an enemy target. The Mk 15 saw no major action in combat until Guadalcanal however, four were used to scuttle the carrier Lexington at the Battle of the Coral Sea. In October 1942, two destroyers fired sixteen torpedoes  to scuttle the carrier Hornet, but they failed to sink the carrier.  The problem with the Mk-15, as with the Mk-14, was the Mk-6 exploder, which employed a magnetic detector to detonate under the target - in theory. In practice, it didn't work.  This resulted in the much researched "Great Torpedo Scandal".

Year of Construction: 1936  
Bore: 21 inches
Weight: 3,841 pounds 
Length: 24 feet  
Ranges: 6,000 yards at 45 knots  
             10,000 yards at 33.5 knots
             15,000 yards at 26.5 knots  
Explosive Charge: 825 pounds Torpex*

*Up until the 1940s trinitrotoluene (TNT) was the explosive of choice because it was cheap to manufacture and, with a melting point of only 177 F, was easily cast into weapons cases. Another explosive invented in 1899, RDX (also called cyclonite, Hexogen and T-4. The chemical name is cyclotrimethylenetrinitramine.  Say that 3 times real fast...), was more powerful but was far too sensitive to be used for military applications. The British and Canadians eventually mixed RDX and TNT together and combined this mixture with powdered aluminum and beeswax.  The new mixture, called TORPEX, produced a more powerful blast and increased brisance (shattering and fragmenting effect).

    I took this while sitting on the operator's bench looking forward.  It shows the entire control panel area. The data plate reads: 

"U.S. Naval Ordnance Plant. 21" Above Water Torpedo Tube Gyro Setting Mechanism, MK 5"

   These are the controls for manually setting the torpedo gyro, depth, and speed and are fitted on top of the torpedo bank. The controls include the Mark 5 Gyro-setting mechanism, Mark 2 Torpedo Course Attachment, Mark 1 Torpedo Course indicator, Mark 2 Depth Setting Mechanism, and Mark 2 Speed-Setting Mechanism.  Man, thatsa lotta Mark 2s! Here we go...


Mark 5 Gyro-setting mechanism.  The dials were not readable.




   Mark 2 Torpedo Course Attachment and the Mark 1 Torpedo Course indicator. The markings on the oval dial at the left reads "Torpedo Course."  The small one at the bottom reads "Tube Train" and appears to be numbered 0-360.  The round dial at the right is also numbered 0-360.  Nothing intuitive about this beast...


   Mark 5 Portable Sight and Angle Solver. This device was mounted to the right of the control panel under a metal cover.  Beneath the cover there was a rotten piece of canvas.  Once I pulled that off, this is what I found. I used every Kleenex in my camera bag to clean it up for this photo.





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    During the 1950s, the Francis M. Robinson (DE 220) was used as a testing platform for the Mark 32 acoustic torpedo. These were not standard issue weapon systems for Destroyer Escorts, simply an interesting footnote. The Mk 32 was developed by the Navy to track down and destroy high speed, long range submarines. In addition to its homing abilities, its ease of launch made it a readily adaptable  weapon. The Mk 32 was not fired from a torpedo tube, but was thrown overboard by a Mark 2 launching system. Once in the water, its homing device guided it unerringly to the target. 
    The Mark 2 launching system consisted of a Mark 4 launcher, three Mk 32 torpedoes, and three storage carts for the torpedoes. 

    This is Joe Dougherty standing next to one of the first Mark 32 torpedoes.  Joe was on the USS Robinson from 3/59 until 6/60. 

Photo contributed by Joe and Kathleen Dougherty.





The Mark 4 launcher throwing a Mark 32 overboard.

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    The triple 12.75" Mark 32 torpedo tube.  This is the tube used to launch the Mk 44 and 46 acoustic-homing torpedoes. The torpedoes were ejected from the tubes with a burst of high pressure air and could be conveniently fitted almost anywhere on the superstructure. I've got one on my front porch.

    The DEs were never equipped with this tube, but the Francis M. Robinson Experimental vessel (EDE-220) performed the developmental and operational testing before fielding to the fleet.  So...another claim to fame...

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Mk 44

    The first Mk 35 Mod 2 torpedoes issued to the Naval Ordnance Unit in Key West, Florida in May 1953.  The men (l-r) are Lt. E. C. White, Naval Ordnance Unit, John W. Persohn, Bureau of Ordnance, and Commander J. C. Wheeler, Commanding Officer, Naval Ordnance Unit.

National Archives #80G483598

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The Mark 108 Launcher, "Weapon ALPHA". As sonar technology progressed, new weapons emerged that took advantage of larger and more accurate detection areas. This weapon, developed at the end of WW2, was essentially a rocket-propelled depth charge that used the 12.75" Mark 1 and Mark 2 underwater rockets.  It provided more flexibility than the hedgehog spigot mortar with increased range and latitude of attack.  The "Alpha" removed the attacker's need  to move into the immediate area of the submarine, as was necessary with conventional depth charges and hedgehog weapons.  The "Alpha" was a surface-to-underwater rocket fired from a launcher that resembled a 5" gun turret. The Alpha replaced the number two 3"/50 mount.  The turret could be turned in almost a complete circle, permitting the Alpha to launch as soon as the target was identified. The rocket sank rapidly and covered a much larger area than traditional depth charges. It was capable of firing either Mark 1 or Mark 2 rockets at a rate of 12 per minute.

The Mark 1 and Mark 2 Rockets carried 250 pounds of either TNT or Torpex and an overall weight of 525 pounds. The tails housed a 5.25" rocket motor. Flight time for the Mark 1 was approximately 10.9 seconds. Flight time for the mark 2 was approximately 14.2 seconds. Both entered the water with a velocity of 1,300 feet per second and had a sink rate of 40 feet per second. Both rockets were triggered with a magnetic influence fuze. The Mark 1 employment ranges were 300 yards minimum and 766 yard maximum. The mark 2 employment ranges were 250 yards minimum and 975 yards maximum.

A different Mark 2 Rocket (not pictured) was a sub-caliber rocket used for ASW training and measured 4" in diameter. It did not contain explosive.

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National Archives #80-G-1018025

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National Archives #80-G-1018026

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National Archives #80-G-643036

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