The Mark 6 exploder was a United States Navy torpedo exploder developed in the 1920s. It was the standard exploder of the Navy's Mark 14 torpedo and Mark 15 torpedo. [lower-alpha 1]
The Mark 6 exploder was a United States Navy torpedo exploder developed in the 1920s. It was the standard exploder of the Navy's Mark 14 torpedo and Mark 15 torpedo. [lower-alpha 1]
Early torpedoes used contact exploders. A typical exploder had a firing pin that stuck out from the warhead and was restrained by a transverse shear pin. The torpedo would hit the target with enough energy to break the shear pin and allow the firing pin to strike a percussion cap that ultimately detonated the warhead. An arming impeller was an additional safety device: the firing pin could not move until the torpedo had traveled a preset distance. [5]
Just before World War I, the Bureau of Ordnance (commonly called BuOrd) started developing an inertial exploder. The result was the Mark 3 exploder. [5]
Warships employed defenses against torpedoes. A new technology, torpedo blisters, appeared on capital ships. The torpedo would explode against the blister but do little damage to the hull. Torpedo blisters were tested on two battleships, the decommissioned South Carolina and the unfinished Washington; the conclusion was the Mark 10 torpedo, with its contact exploder, could not disable a major warship. [6] Torpedoes would need to explode underneath a capital ship, where there were no blisters or other armor. [7] The Mark 14 torpedo was designed at the Newport Torpedo Station (NTS), Newport, to replace the Mark 10, which had been in service since World War I. Its fairly small 643 lb (292 kg) warhead [8] required it to explode beneath the keel where there was no armor. [7]
This led to the development of a magnetic influence feature, similar to the British Duplex [9] and German [10] models, all inspired by German magnetic mines of World War I. [7] The Mark 6 was intended to fire the warhead beneath the ship, creating a huge gas bubble which would cause the keel to fail catastrophically.[ citation needed ]
The Mark 6 exploder, designated Project G53, [11] was developed "behind the tightest veil of secrecy the Navy had ever created." [11] In less than two years, Newport Torpedo Station produced a prototype with help from General Electric. The prototype exploder was fitted to a Mark 10 torpedo and test-fired in Narragansett Bay on 8 May 1926; the submarine USS L-8 was the target. [12]
In the first test, the torpedo ran underneath the target submarine but did not explode; a second test was successful. Those two shots were the only live-fire tests until World War II. After several redesigns, General Electric in Schenectady made 30 production units, at a cost of US$1,000 apiece. [13] [14] [15] The exploder was tested at the Newport lab and in a small field test aboard USS Raleigh.
At the urging of Lt. Ralph W. Christie, who headed the Mark 14's design team, equatorial tests were later conducted by USS Indianapolis, which fired one hundred trial shots between 10°N and 10°S [16] and collected 7,000 readings. [17] The tests were done using torpedoes with instrumented exercise heads: an electric eye would take an upward-looking picture from the torpedo; the magnetic influence feature would set off some gun cotton. [16]
Due to budgetary constraints, very few live-fire trials of the torpedo or exploder were ever conducted. The goal of most exercise firings was to get the torpedo to run under the target, after which it was assumed the magnetic influence feature would do the work. This misplaced trust in the magnetic exploder helped mask the depth problems encountered by early torpedoes, for if the exploder were to work properly a depth error of a few feet would not matter. [18] Chief of Naval Operations William V. Pratt offered the hulk of Cassin-class destroyer USS Ericsson, [17] [19] but prohibited the use of a live warhead, and insisted BuOrd pay the cost of refloating her if she was hit in error. [17] These were strange restrictions, as Ericsson was due to be scrapped. [20] BuOrd declined. [17] A service manual for the exploder "was written—but, for security reasons, not printed—and locked in a safe." [17]
After the Mark 14 entered combat service in the Pacific War, it was discovered the torpedo had several major flaws. Two of these were directly related to the Mark 6 exploder:
Similar problems also plagued the Mark 15 torpedo used by U.S. Navy destroyers. The problems could lead to misses or failures, and tended to mask one another, making isolating any one of them more difficult. [18] [ page needed ]
Many submarine commanders in the first two years of the war reported explosions of the warhead with little to no damage of the enemy. The magnetic exploders were triggering prematurely, before getting close enough to the vessel to destroy it. Earth's magnetic field near NTS, where the trials (limited as they were) [21] were conducted, differed from the areas where the fighting was taking place.
Early reports of torpedo action included some dud hits, heard as a dull clang. In a few instances, Mark 14s would strike a Japanese ship and lodge in its hull without exploding. The contact pistol appeared to be malfunctioning, though the conclusion was anything but clear until running depth and magnetic exploder problems were solved. This experience was exactly the sort of live-fire trial BuOrd had been prevented from doing in peacetime, causing one submarine skipper to complain, "[Making] round trips of 8,500 miles (13,700 km) into enemy waters to gain attack positions undetected within 800 yards (730 m) of enemy ships only to find that torpedoes run deep and over half the time fail to function, seems to me an undesirable method of gaining information which might be determined any morning within a few miles of a torpedo station in the presence of comparatively few hazards." [18] It was now clear to all at Pearl Harbor that the contact pistol was also defective.
Against orders, some submariners disabled the magnetic influence feature of the Mark 6 exploder, suspecting it was faulty. An increase in hits was reported. Shortly after replacing Wilkes in Fremantle, [22] Rear Admiral [22] Charles Lockwood ordered a historic net test at Frenchman Bay on 20 June 1942. [23] Eight hundred Mark 14s had already been fired in combat. [23]
After a historic net test by Jim Coe's Skipjack, BuOrd on 1 August 1942 finally conceded the Mark 14 ran deep, and six weeks later, "that its depth-control mechanism had been 'improperly designed and tested'". [8] This satisfied Lockwood and Robert H. English (then COMSUBPAC), [24] who both refused to believe the exploder could also be defective. [8]
Finally, in July 1943, Admiral Lockwood (by then COMSUBPAC) ordered his boats to deactivate the Mark 6's influence feature and use only its contact pistol. [25]
Tests were carried out by COMSUBPAC's gunnery and torpedo officer, Art Taylor (ex-Haddock). Taylor, "Swede" Momsen, and others fired warshots from Muskallunge [26] into the cliffs of Kahoolawe, beginning 31 August. Their third test shot was a dud. [27] This revealed the firing pin had not been able to contact the detonator hard enough to fire the warhead. [27]
To avoid "shaking hands with St. Peter" (as Lockwood put it), [27] E.A. Johnson, USNR, supervised by Taylor, dropped dummy warheads filled with sand from a crane raised to a height of 90 feet (27 m). In 7 out of 10 of these trials, firing mechanisms bent, jammed, and failed with the high inertia of a straight-on hit (the prewar ideal). [28] A quick fix was to encourage "glancing" shots [29] (which cut the number of duds in half), [28] until a permanent solution could be found. Lightweight aluminum alloy (from propellers [28] of Japanese planes shot down during the attack on Pearl Harbor) was machined to take the place of the Mark 6's heavy pin block so inertial forces would be lower. Electrical switches, developed by Johnson, [28] were tried as well. Both fixes worked and were relatively easy to implement. In September 1943, the first torpedoes with new contact pistols were sent to war. [30] "After twenty-one months of war, the three major defects of the Mark 14 torpedo had at last been isolated. ... Each defect had been discovered and fixed in the field—always over the stubborn opposition of the Bureau of Ordnance." [29]
A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, such a device was called an automotive, automobile, locomotive, or fish torpedo; colloquially a fish. The term torpedo originally applied to a variety of devices, most of which would today be called mines. From about 1900, torpedo has been used strictly to designate a self-propelled underwater explosive device.
A depth charge is an anti-submarine warfare (ASW) weapon designed to destroy submarines by detonating in the water near the target and subjecting it to a destructive hydraulic shock. Most depth charges use high explosives with a fuze set to detonate the charge, typically at a specific depth from the surface. Depth charges can be dropped by ships, patrol aircraft and helicopters.
USS Sailfish (SS-192), was a US Sargo-class submarine, originally named Squalus. As Squalus, the submarine sank off the coast of New Hampshire during test dives on 23 May 1939. The sinking drowned 26 crew members, but an ensuing rescue operation, using the McCann Rescue Chamber for the first time, saved the lives of the remaining 33 aboard. Squalus was salvaged in late 1939 and recommissioned as Sailfish in May 1940.
The Naval Undersea Warfare Center (NUWC) is the United States Navy's full-spectrum research, development, test and evaluation, engineering and fleet support center for submarines, autonomous underwater systems, and offensive and defensive weapons systems associated with undersea warfare. It is one of the corporate laboratories of the Naval Sea Systems Command. NUWC is headquartered in Newport, Rhode Island and has two major subordinate activities: Division Newport and Division Keyport in Keyport, Washington. NUWC also controls the Fox Island facility and Gould Island. It employs more than 4,400 civilian and military personnel, with budgets over $1 billion.
USS Cachalot (SC-4/SS-170) was a United States Navy submarine and the lead ship of her class, known as the "V-boats" and named for the sperm whale. Her keel was laid down by the Portsmouth Navy Yard. She was launched on 19 October 1933 as V-8 (SC-4) sponsored by Miss K. D. Kempff, and commissioned on 1 December 1933 with Lieutenant Commander Merril Comstock in command. Cachalot was the first submarine to have the Torpedo Data Computer, Arma Corporation's Mark 1, installed.
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USS Tinosa (SS-283), a Gato-class submarine, was the first ship of the United States Navy to be named for the tinosa.
An anti-submarine weapon (ASW) is any one of a number of devices that are intended to act against a submarine and its crew, to destroy (sink) the vessel or reduce its capability as a weapon of war. In its simplest sense, an anti-submarine weapon is usually a projectile, missile or bomb that is optimized to destroy submarines.
Charles Andrews Lockwood was a vice-admiral and flag officer of the United States Navy. He is known in submarine history as the commander of Submarine Force Pacific Fleet during World War II. He devised tactics for the effective use of submarines, making the members and elements of "silent service" key players in the Pacific victory.
The Mark 45 anti-submarine torpedo, a.k.a. ASTOR, was a submarine-launched wire-guided nuclear torpedo designed by the United States Navy for use against high-speed, deep-diving, enemy submarines. This was one of several weapons recommended for implementation by Project Nobska, a 1956 summer study on submarine warfare. The 19-inch (480 mm)-diameter torpedo was fitted with a W34 nuclear warhead. The need to maintain direct control over the warhead meant that a wire connection had to be maintained between the torpedo and submarine until detonation. Wire guidance systems were piggybacked onto this cable, and the torpedo had no homing capability. The design was completed in 1960, and 600 torpedoes were built between 1963 and 1976, when ASTOR was replaced by the Mark 48 torpedo.
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The Mark 37 torpedo is a torpedo with electrical propulsion, developed for the US Navy after World War II. It entered service with the US Navy in the early 1950s, with over 3,300 produced. It was phased out of service with the US Navy during the 1970s, and the stockpiles were sold to foreign navies.
The Mark 14 torpedo was the United States Navy's standard submarine-launched anti-ship torpedo of World War II. This weapon was plagued with many problems which crippled its performance early in the war. It was supplemented by the Mark 18 electric torpedo in the last two years of the war. From December 1941 to November 1943 the Mark 14 and the destroyer-launched Mark 15 torpedo had numerous technical problems that took almost two years to fix. After the fixes, the Mark 14 played a major role in the devastating blow U.S. Navy submarines dealt to the Japanese naval and merchant marine forces during the Pacific War.
The Mark 15 torpedo was the standard American destroyer-launched torpedo of World War II. It was very similar in design to the Mark 14 torpedo except that it was longer, heavier, and had greater range and a larger warhead. The Mark 15 was developed by the Naval Torpedo Station Newport concurrently with the Mark 14 and was first deployed in 1938. It served as a replacement for the Mark 8 torpedo, Mark 11 Torpedo and Mark 12 Torpedo on surface ships with tubes that could accommodate the longer Mark 15; this primarily included destroyers built after 1930. Older destroyers, primarily the Wickes and Clemson classes, continued to use the Mark 8, as did PT boats early in World War II. During the war 9,700 were produced at Newport and at the Naval Ordnance Station Forest Park, Illinois.
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A nuclear torpedo is a torpedo armed with a nuclear warhead. The idea behind the nuclear warheads in a torpedo was to create a much bigger explosive blast. Later analysis suggested that smaller, more accurate, and faster torpedoes were more efficient and effective.
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