Mark 14 torpedo
|Mark 14 torpedo|
Mark 14 torpedo side view and interior mechanisms, as published in a service manual
|Type||Anti-surface ship torpedo|
|Place of origin||United States|
|In service||1931[dubious ]–1980|
|Used by||United States Navy|
|Wars||World War II|
|Designer||Naval Torpedo Station Newport, Rhode Island|
|Manufacturer||Naval Torpedo Station Newport, RI
Naval Torpedo Station Alexandria, VA
Naval Torpedo Station Keyport, Washington
Naval Ordnance Plant Forest Park, IL
|Weight||3,280 lb (1,490 kg)|
|Length||20 ft 6 in (6.25 m)|
|Diameter||21 in (530 mm)|
|Effective firing range||4,500 yards (4,100 m) at 46 knots (85 km/h)
9,000 yards (8,200 m) at 31 knots (57 km/h)
|Warhead weight||643 lb (292 kg)|
|Contact or magnetic pistol|
|Engine||Wet-heater combustion / steam turbine with compressed air tank|
|Speed||46 knots (85 km/h)|
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. Nonetheless, the Mark 14 played a major role in the devastating blow US Navy submarines dealt to the Japanese naval and merchant marine forces during the Pacific War.
By the end of World War II, the Mark 14 torpedo was a reliable weapon which remained in service for almost 40 years in the US Navy, and even longer with other navies.
- 1 Development
- 2 Supply and production
- 3 Controversy
- 4 Well-documented failures
- 5 Problems
- 6 Solutions
- 7 Nomenclature
- 8 Characteristics
- 9 Notes
- 10 References
- 11 Further reading
- 12 External links
The design of the Mark 14 started in January 1931; the Navy allocated $143,000 for its development (equivalent to $2,225,105 in 2015). The Mark 14 was to serve in the new "fleet" submarines and replace the Mark 10 which had been in service since World War I and was standard in the older R- and S-boats. Although the same diameter, the Mark 14 was longer, at 20 ft 6 in (6.25 m), and therefore incompatible with older submarines' 15 ft 3 in (4.65 m) torpedo tubes. (Later in the war, BuOrd stopped producing Mark 10s for the S-boats and provided a shortened Mark 14.)
Torpedoes consist of several subsystems, and those subsystems evolved over time. Torpedoes are also tailored for their application. Submarine torpedoes, such as the Mark 14, are constrained by the dimensions of the submarines torpedo tubes: 21 inches in diameter an certain length. Submarines are expected to close with their targets, so the torpedoes do not need a long range. In contrast, torpedoes fired by destroyers need greater range because their approach would be under fire from their targets. Improvements in the propulsion engine power output allowed the Mark 14 to have a top speed of 46 knots compared to the Mark 10 Mod 0's 30 knots. Steering is controlled by a gyroscope; the gyro on the Mark 10 Mod 0 was spun up in the torpedo tube and was not powered after launch; the gyro on the Mark 14 was continuously powered by its air flask. The depth control on the Mark 10 was slow — the depth would not stabilize quickly; the Mark 14 depth stabilization was improved.
The design for the Mark 6 exploder used in the Mark 14 torpedo had started at the Naval Torpedo Station (NTS), Newport, in 1922. It had a fairly small warhead and was intended to explode beneath the keel where there was no armor. This required the sophisticated new Mark 6 magnetic influence exploder, which was similar to the British Duplex and German models, all inspired by German magnetic mines of World War I. The Mark 14 shared this exploder with the concurrently-designed surface ship Mark 15 torpedo.
The Mark 6 exploder, designated Project G53, was developed "behind the tightest veil of secrecy the Navy had ever created." Exploders were tested at the Newport lab and in a small field test aboard USS Raleigh. At Ralph Christie's urging, equatorial tests were later conducted with USS Indianapolis, which fired one hundred trial shots between 10°N and 10°S and collected 7000 readings. 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. Inexplicably, no live fire trials were ever done with production units. Chief of Naval Operations William V. Pratt offered the hulk of Cassin-class destroyer Ericsson, but prohibited the use of a live warhead, and insisted the Bureau of Ordnance (commonly called BuOrd) pay the cost of refloating her if she was hit in error. These were strange restrictions, as Ericsson was due to be scrapped. BuOrd declined. A service manual for the exploder "was written—but, for security reasons, not printed—and locked in a safe."
Torpedoes were sophisticated and expensive. The cost of a torpedo in 1931 was about $10,000 (equivalent to $155,602 in 2015). The development of the Mark 13, Mark 14 and Mark 15 torpedoes was done frugally. The Navy did not want to do live fire tests that would destroy a $10,000 torpedo. The Navy was also reluctant to supply target ships. Consequently, there were no live fire tests, and the designers had to rely on their judgment. Sadly, that judgment sometimes led to problems: a contact exploder that worked reliably at 30 knots (15 m/s) failed at 46 knots (24 m/s). In addition, the Navy had limited experience in using torpedoes in combat.
Supply and production
The US Navy has a long history of torpedo supply problems. In 1907, the Navy knew there was a problem with torpedo supply; a major contractor, the E. W. Bliss Company, could produce only 250 torpedoes per year. During World War I, the Navy had almost 300 destroyers that each had 12 torpedo tubes. The Bliss Company was to produce about 1,000 torpedoes for the Navy, but that production was delayed by demands for artillery shells and only 20 torpedoes were close to being shipped before WWI started for the US. When war was declared on Germany, another 2,000 torpedoes were ordered. In order to produce large numbers of torpedoes, the government loaned $2 million to Bliss Company so it could build a new factory. Although the government had ordered 5,901 torpedoes, only 401 had been delivered by July 1918. The supply problems prompted the Navy to build the U.S. Naval Torpedo Station, Alexandria, VA, but WWI ended before the plant was built. The plant produced torpedoes for five years, but was shutdown in 1923.
In 1923, Congress made NTS Newport the sole designer, developer, builder and tester of torpedoes in the United States. No independent or competing group was assigned to verify the results of Mark 14 tests.
The Navy had not learned from the torpedo supply lessons of WWI. Looking back in 1953, the Bureau of Ordinance stated, "Production planning in the prewar years was also faulty. Torpedoes were designed for meticulous, small-scale manufacture. When military requirements demanded that they be supplied in large numbers, a series of new problems were exposed. There were simply no realistic plans available for providing the weapon in adequate quantity." There was little interest in torpedo production until 1933 when the Vinson Shipbuilding Program recognized the need for torpedoes to fill the torpedo tubes on its newly constructed ships. Consequently, Newport received new production equipment and an increased budget. NTS produced only 1½ torpedoes a day in 1937, despite having three shifts of three thousand workers working around the clock. Production facilities were at capacity and there was no room for expansion.
By January 1938, unfilled torpedo orders at Newport amounted to $29,000,000. A forecast that did not include war estimated Newport would have a backlog of 2425 torpedoes by 1 July 1942. More production was needed. The simplest route was to reopen the Alexandria Torpedo Station, but New England congressmen objected to reopening Alexandria; they wanted production concentrated in New England. The Navy side-stepped the opposition by including the Alexandria funds as part of the Naval Gun Factory's 1939 budget. The Naval Torpedo Station at Keyport, Washington, was also expanded.
"Although torpedo production was still low — 3 a day — when the national emergency was proclaimed in September 1939, an investment of almost $7,000,000 assured early improvement." By the fall of 1941, Alexandria had been reopened. The required production rate for torpedoes was raised to 50 per day. Both Newport and Alexandria went to 3 shifts operating 7 days per week, but their combined torpedo production was 23 torpedoes per day. The Navy contracted with the American Can Company to produce torpedoes.
After the U.S. entered the war, the contract with American Can was expanded and Pontiac Motor Company, International Harvester, E. W. Bliss Company, and Precision Manufacturing Co. were brought in as contractors. In May 1942, Westinghouse Electric Corporation was asked to build an electric torpedo (which would become the Mark 18 torpedo).
Only two thousand submarine torpedoes were built by all three Navy factories (Newport, Alexandria, and Keyport) during 1942. This exacerbated torpedo shortages; the Pacific Fleet Submarine Force had fired 1,442 torpedoes since war began.
The torpedo shortage at the start of the war also meant that commanders did not want to waste torpedoes on testing.
The Mark 14 was central to the torpedo scandal of the U.S. Pacific Fleet Submarine Force during World War II. Inadequate production planning led to severe shortages of the weapon. The frugal, Depression-era, peacetime testing of both the torpedo and its exploder was woefully inadequate and had not discovered many serious design problems. Torpedoes were so expensive that the Navy was unwilling to perform tests that would destroy a torpedo. Furthermore, the design defects tended to mask each other. Much of the blame commonly attached to the Mark 14 correctly belongs to the Mark 6 exploder. These defects, in the course of fully twenty months of war, were exposed, as torpedo after torpedo either missed by running directly under the target, prematurely exploded, or struck targets with textbook right angle hits (sometimes with an audible clang) and failed to explode.
Responsibility lies with the BuOrd, which specified an unrealistically rigid magnetic exploder sensitivity setting and oversaw the feeble testing program. Its pitiful budget did not permit live fire tests against real targets; instead, any torpedo that ran under the target was presumed to be a hit due to the magnetic influence exploder, which was never actually tested. Therefore, additional responsibility must also be assigned to the United States Congress, which cut critical funding to the Navy during the interwar years, and to NTS, which inadequately performed the very few tests made. BuOrd failed to assign a second naval facility for testing, and failed to give Newport adequate direction.
On 24 December 1941, Commander Tyrell D. Jacobs in Sargo fired a total of eight torpedoes at two different ships, with no results, and had become very frustrated; when two additional merchantmen came in view, he took extra pains to get it right, pursuing for fifty-seven minutes and making certain TDC bearings matched perfectly before firing two torpedoes at each ship, at an average of 1,000 yd (910 m), very close range. All missed.
A few days after he discovered the torpedoes were running too deep, and corrected the problem, Jacobs detected a big, slow tanker. Again, his approach was meticulous, firing one torpedo at a close 1,200 yd (1,100 m). It missed. Exasperated, Jacobs broke radio silence, openly questioning the Mark 14's reliability.
Uniquely, Lieutenant Commander John A. Scott in Tunny on 9 April 1943 found himself in an ideal position to attack aircraft carriers Hiyo, Junyo, and Taiyo. From only 880 yd (800 m), he fired all ten tubes, hearing all four stern shots and three of the bow's six explode. No enemy carrier was seen to diminish its speed, though Taiyo was slightly damaged in the attack. Much later, intelligence reported each of the seven explosions had been premature; the torpedoes had run true but the magnetic feature had fired them too early.
Dan Daspit (in Tinosa) carefully documented his efforts to sink 19,000-ton whale factory ship Tonan Maru III on 24 July 1943. He fired four torpedoes from 4,000 yd (3,700 m); two hit, stopping the target dead in the water. Daspit immediately fired another two; these hit as well. With no enemy anti-submarine combatants in sight, Daspit then took time to carefully maneuver into a textbook firing position, 875 yd (800 m) square off the target's beam, where he fired nine more Mark 14s and observed all with his periscope (despite the Japanese firing at it). All were duds. Daspit, suspicious by now he was working with a faulty production run of Mark 14s, saved his last remaining torpedo to be analyzed by experts back at base. Nothing out of the ordinary was found.
At Pearl Harbor, despite nearly all his skippers' suspicions about the torpedoes, Admiral Thomas Withers refused to deactivate the torpedo's Mark 6 exploder, arguing torpedo shortages stemming from inadequate production at NTS made it impossible. As a result, his men did it on their own, doctoring their patrol reports and overstating the size of ships to justify using more torpedoes. Only in May 1943, after the most famous skipper in the Sub Force, Dudley W. "Mush" Morton, turned in a dry patrol, did Admiral Charles A. Lockwood, Commander Submarine Force Pacific (COMSUBPAC), accept the Mark 6 should be deactivated, but waited to see if Bureau of Ordnance commander Admiral William "Spike" Blandy might yet find a fix for the problem. The Bureau of Ordnance sent an expert to Surabaja to investigate, who set the gyro backwards on one of Sargo's trial torpedoes; the potentially deadly setting, guaranteed to cause erratic running, was corrected by torpedo officer Doug Rhymes. Though he found nothing wrong with maintenance or procedures, the expert submitted a report laying all the blame on the crew.
The Mark 14 torpedo had four major flaws.
- It tended to run about 10 feet (3.0 m) deeper than set.
- The magnetic exploder often caused premature firing.
- The contact exploder often failed to fire the warhead.
- It tended to run "circular", failing to straighten its run once set on its prescribed gyro-angle setting, and instead, to run in a large circle, thus returning to strike the firing ship.
Some of these flaws had the unfortunate property of masking or explaining other flaws. The torpedo running too deeply would explain the magnetic influence exploder failing to explode underneath a ship. When the depth issue was fixed, the magnetic influence exploder's premature detonation made it look like the contact exploder was working.
Running too deep
Deep running torpedoes had been seen before. In January 1942, BuOrd told the fleet that the Mark 10 torpedo ran 4 feet (1.2 m) deeper than set. The reasons for deeper running are not explained, but the Mark 10 torpedo's speed had been increased from 30 to 36 knots, its warhead had been increased from 400 pounds to 497 pounds of TNT, and its had an updated guidance package.
The Mark 14 torpedo tended to run some ten feet (3 meters) too deep for several reasons. The first was that it was only tested with an exercise warhead filled with water to set the depth. However, the live warhead contained more mass than that, and it reached buoyancy equilibrium at a lower depth. Also, the depth mechanism was designed prior to the warhead's charge being increased, making the torpedo even heavier overall. Furthermore, two depth testing devices used by NTS to verify results were both off by the same amount in the same direction, which compounded the problem. After hearing of the problem, most submarine skippers simply set their torpedoes' running depth to zero, risking a broach. By August 1942, the faulty running depth situation was in hand and submarines were getting more hits with the Mark 14. However, curing the deep-running problem caused more prematures and duds, as more hits were being achieved. The number of sinkings did not rise.
Torpedo depth is a control problem; good depth control requires more than just measuring the torpedo's depth. A depth control system that used just depth (measured by a hydrostat) to control the elevators would tend to oscillate around the desired depth. Whitehead in Fiume supplied many of the world's navies, and it had trouble with depth control until it developed the "balance chamber" with pendulum (pendulum-and-hydrostat control). The balance chamber had water pressure push against a disk that was balanced by a spring. "The inclusion of a pendulum stabilized the mechanism's feedback loop." This development (known as "The Secret") was around 1868.
Torpedo depth control had been done with a pendulum mechanism that limited the torpedo to shallow pitches of less than 1 degree. The shallow angle meant that it could take a long time for a torpedo to stabilize at its desired depth. The improved Uhlan mechanism (Uhlan gear) for depth control had been introduced in the Mark 11 torpedo.
When the Uhlan gear was incorporated in the Mark 14 design, the pressure sensing port for the depth mechanism was moved from its forward position to the cone-shaped tail section; the designers did not realize that move would affect the pressure readings. The repositioning meant a hydrodynamic flow effect when the torpedo was moving created a substantially lower pressure at the port than hydrostatic depth pressure. The torpedo's depth control engine therefore thought the torpedo was too shallow depth and responded by trimming the torpedo to run deeper. A laboratory test (such as immersing a non-moving torpedo in a pool of water) would show the torpedo trimmed at the desired depth. The problem was also exacerbated by higher speeds. The depth problem was finally addressed in the last half of 1943 by relocating the sensor point to the midbody of the torpedo where hydrodynamic effects were minimized.
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) were conducted, differed from the areas where the fighting was taking place.
There were two common types of premature explosions. In the first, the warhead exploded just as it armed. These premature explosions were easily discerned by the submarine because the torpedo exploded before it had a chance to reach its target. In the second, the warhead exploded just before reaching the target ship but far enough away that it did no damage. The skipper, looking through the periscope, could see the torpedo run right to the ship and see the explosion; the crew could hear the high order explosion. Everything would look OK except that the target ship would get away with little or no damage. Sometimes the submarine command would hear about these premature explosions from intercepted enemy communications.
Both premature explosion types could result from the magnetic influence exploder. If a torpedo was still turning to get on course or had not stabilized its depth when the warhead armed, the exploder could see a magnetic field change and detonate. As the warhead approached the target, it could sense a change due to the ship's affect on the earth's magnetic field. That's a desired effect if the torpedo is set to run under the ship, but not a desirable effect when the torpedo is set to hit the side of the ship.
Another explanation for early premature explosions was electrical failure due to leaking gaskets.
The second type of premature explosion masked contact exploder failures. Skippers firing the torpedo for a contact exploder hit on the side of the target would see an explosion and believe the contact exploder worked, but the explosions were triggered not by the contact feature, but rather by the magnetic influence feature at a distance far enough from the hull to cause little or no damage.
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. Daspit's experience was exactly the sort of live-fire trial BuOrd had been prevented from doing in peacetime. It was now clear to all at Pearl Harbor the contact pistol was also defective. Ironically, a direct hit on the target at a 90 degree angle, as recommended in training, would usually fail to detonate; the contact pistol functioned reliably only when the torpedo impacted the target at an oblique angle.
There were numerous reports of the Mark 14 running erratically and circling back on the firing boat. A circular run sank the submarine Invalid Optional Parameter, but it may not have been a Mark 14. Likewise, Sargo was almost sunk by a circular, but the circular run happened because the gyro had not been installed. The subsequent Mark 18 torpedo was no better, sinking Tang. The Mark 15 torpedo had collars to prevent circular runs, but the Mark 14 was never given this feature.
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, newly minted Rear Admiral Lockwood ordered a historic net test at Frenchman Bay on 20 June 1942. Eight hundred torpedoes had already been fired in combat, more than a year's production from NTS.
Jim Coe's Skipjack did the honors, firing a single fish with an exercise head, set at 10 ft (3.0 m), from 850 yards (780 m). It hit the net at a depth of 25 ft (7.6 m). Not satisfied, James Fife, Jr. (formerly Chief of Staff to COMSUBAS John E. Wilkes, whom Lockwood was replacing in Perth-Fremantle) followed up the next day with two more test shots; Fife concluded they ran an average 11 ft (3.4 m) deeper than the depth at which they were set. BuOrd was not amused. Neither was the CNO, Admiral Ernest J. King, who "lit a blowtorch under the Bureau of Ordnance". The fact that destroyers' Mark 15s were suffering the same failures may have had something to do with it, as well. On 1 August 1942, BuOrd finally conceded the Mark 14 ran deep, and six weeks later, "that its depth-control mechanism had been 'improperly designed and tested'".
The deep running torpedoes would explain many warshot misses: a torpedo running too deeply under the target would not allow the magnetic influence exploder to detect the target. Getting the torpedoes to run at the correct depth would presumably fix the problem of the torpedoes failing to explode. This explanation satisfied Lockwood and Robert H. English (then COMSUBPAC), who both refused to believe the exploder could also be defective. In August 1942, the submarine command thought the torpedo reliability problem was solved.
The skippers, however, continued to report problems with the Mark 14. Suspicion about the magnetic influence exploder grew.
On 9 April 1943, USS Tunny attacked an aircraft carrier formation. ULTRA intercepts disclosed that all three torpedoes fired at the second carrier were premature explosions. The commanding officer stated, "The shallow [depth] setting thus caused the torpedo to reach the activating flux density of the exploder some fifty meters from the target."
On 10 April 1943, Bureau of Ordnance Chief Admiral Blandy wrote Lockwood that the Mark 14 was likely to premature at shallow depths. Blandy recommended that the magnetic influence feature be disabled if torpedoes were fired for contact hits.
BuOrd also concluded that the Mark 14's arming distance of 450 yards was too short; an arming distance of 700 yards would be needed for most torpedoes to stabilize their course and depth. BuOrd also believed the Mark 6 magnetic influence feature was less effective below 30°N latitude and did not recommend its use below 30°S latitude.
On May 8 1943, Lockwood made a list of torpedo failures gleaned from ULTRA intercepts.
On 10 June 1943, USS Trigger fired six torpedoes from 1200 yards at the aircraft carrier Hiyo. Two torpedoes missed, one exploded prematurely, one was a dud, and two hit. The carrier was damaged but made it home.
In late June 1943, Admiral Lockwood (by then COMSUBPAC) asked Commander-in-Chief of the Pacific Fleet (CINCPAC) Chester Nimitz for permission to deactivate the magnetic exploders. The next day, 24 June 1943, CINCPAC ordered all of his submarines to deactivate the magnetic exploder.
Admiral Christie, who had been involved in the development of the magnetic influence exploder, was now commander of the Australian-based submarines in the South West Pacific Area and not in Nimitz' chain of command. Christie insisted his area's submarines continue to use the magnetic exploder. At the end of 1943, Admiral Thomas C. Kinkaid replaced Admiral Arthur S. Carpender as Commander Allied Naval Forces South West Pacific Area (Christie's boss) and ordered Christie to deactivate the magnetic influence exploder.
Once the magnetic influence exploder was deactivated, problems with the contact exploder became more apparent. Torpedoes would hit their target without detonating. There might be a small "explosion" when the air flask ruptured due to the impact with the target.
Daspit's cruise raised enough of an issue that tests were carried out by COMSUBPAC's gunnery and torpedo officer, Art Taylor. Taylor, "Swede" Momsen, and others fired warshots into the cliffs of Kahoolawe, beginning 31 August. Additional trials, supervised by Taylor, used a crane to drop warheads filled with sand instead of high explosive from a height of 90 feet (27 m) (the height was chosen so the terminal velocity would match the torpedo's running speed of 46 knots). In these drop tests, 70% of the exploders failed to detonate when they hit the target at 90 degrees. A quick fix was to encourage "glancing" shots (which cut the number of duds in half), until a permanent solution could be found.
In September 1943, the first torpedoes with new contact pistols were sent to war. "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."
Once remedied, sinkings of enemy ships rose noticeably. By the end of World War II the Mark 14 torpedo had become a much more reliable weapon. Lessons learned allowed surface ships such as destroyers to remedy the failings of the Mark 15; the two designs shared the same strengths and faults.
After the war, the best features of the improved Mark 14 were merged with the best features of captured German torpedoes to create the hydrogen peroxide–fueled Mark 16 with a pattern-running option. The Mark 16 became the standard United States post-war anti-shipping torpedo, despite the large remaining inventory of Mark 14 torpedoes.
Official US Navy naming policy had settled on using Arabic instead of Roman numerals to designate torpedo models since the 1917 development of the Bliss-Leavitt Mark 4 torpedo. However, many instances exist of the Mark 14 being referred to as the "Mark XIV" in official documentation and reports as well as accounts by historians and observers.
- Function: Anti-ship
- Powerplant: Wet-heater combustion / steam turbine with compressed air tank
- Fuel: Methanol
- Length: 20 ft 6 in (6.25 m)
- Weight: 3,280 lb (1,490 kg)
- Diameter: 21 in (530 mm)
- Range / Speed:
- Low speed: 9,000 yards (8,200 m) at 31 knots (57 km/h)
- High speed: 4,500 yards (4,100 m) at 46 knots (85 km/h)
- Guidance system: Gyroscope
- Warhead: 643 lb (292 kg) of Torpex
- Date deployed: 1931
- Date withdrawn from service: 1975–1980
- Jolie, E.W. (15 September 1978). "A Brief History of U.S. Navy Torpedo Development". Retrieved 2013-06-05.
- Wildenberg & Polmar 2010, p. 60
- Rowland & Boyd 1953, p. 95
- Wildenberg & Polmar 2010, pp. 218, 219
- Blair 1975, p. 278
- Blair 1975, p. 54
- Fitzsimons, Bernard, general editor. The Illustrated Encyclopedia of 20th Century Weapons and Warfare (London: Phoebus Publishing, 1978), Volume 8, p.807, "Duplex"
- Dönitz, Memoir.
- Blair 1975, p. 55
- Wildenberg & Polmar 2010, p. 65
- Blair 1975, pp. 61–62
- Blair 1975, p. 62
- Fitzsimons, Volume 5, p.541, table.
- Between 1934 and 1936. Fitzsimons, Volume 5, p.542, "Cassin".
- Wildenberg & Polmar 2010, p. 60; stating that $803,000 was allocated for the production of 76 torpedoes.
- Wildenberg & Polmar 2010, p. 63
- Wildenberg & Polmar 2010, p. 48
- Wildenberg & Polmar 2010, p. 52
- Wildenberg & Polmar 2010, p. 53
- Wildenberg & Polmar 2010, p. 55
- Rowland & Boyd 1953, p. 91
- Rowland & Boyd 1953, p. 124
- Rowland & Boyd 1953, p. 125
- Blair 1975, p. 69
- Blair 1975, p. 281
- Rowland & Boyd 1953, p. 125
- Rowland & Boyd 1953, p. 125
- Rowland & Boyd 1953, p. 126
- Wildenberg & Polmar 2010, p. 69
- Rowland & Boyd 1953, p. 126
- Wildenberg & Polmar 2010, p. 105
- Rowland & Boyd 1953, p. 127
- Blair 1975, p. 69
- Blair 1975, p. 553
- Poole, Lisa (1989). Torpedo Town U.S.A. Diamond Anniversary Publishing. ISBN 0-9621829-0-7.
- Rowland & Boyd 1953, p. 96 stating, "what was worse, however, was the diabolical way in which each defect concealed another."
- Morison, Samuel E., History of United States Naval Operations in World War II, IV, pp. passim
- Roscoe 1967
- Blair 1975, p. 141
- Blair 1975, p. 140
- Blair 1975, p. 141. BuOrd would wait months to do the same.
- Blair, pp.140-141 & 169
- Blair 1975, p. 171
- Blair 1975, p. 413
- When he returned, Daspit was livid. Blair 1975, pp. 435–437
- Blair 1975, p. 216
- Blair 1975, p. 206
- Blair 1975, p. 206. This helps explain why U.S. tonnage claims per ship were routinely about a third higher than actual sinkings.
- Blair 1975, p. 427
- Blair 1975, pp. 169–170
- Newpower (2006, p. xii) claims there were 24 cases of circular running torpedoes, but avoids the topic because "it is not clear that any particular defect caused any or all of these circular runs." USS Tang was sunk by a Mark 18 (not a Mark 14); USS Tullibee may have been sunk by a Mark 18. USS Sargo had a circular run because the gyro was not installed.
- Rowland & Boyd 1953, p. 95
- Wildenberg & Polmar 2010, p. 218 showing differences in Mark 10 Mod 0 and Mark 10 Mod 3.
- Scott, James (2013). The War Below: The Story of Three Submarines That Battled Japan. Simon and Schuster. p. 88. ISBN 143917685X.
- Shireman, Douglas A. (February 1998). "U.S. Torpedo Troubles During World War II". World War II.
- Blair 1975, p. 292
- Newpower 2006, p. 12 citing Gray, Edwyn (1991), The Devil's Device: Robert Whitehead and the History of the Torpedo, Annapolis, MD: US Naval Institute, p. 33.
- Sleeman, C. W. (1880), Torpedoes and Torpedo Warfare, Portsmouth: Griffin & Co., pp. 137–138,
which constitutes what is termed as the secret of the fish torpedo.
- Rowland & Boyd 1953, p. 96
- Wildenberg & Polmar 2010, p. 58
- Rowland & Boyd 1953, pp. 96–97
- "The Great Torpedo Scandal of 1941 - 1943", The Submarine Review, October 1996
- Patrick, John (Winter 2012), "The Hard Lessons of World War II Torpedo Failures", Undersea Warfare (47)
- Milford, Frederick J. "U. S. Navy Torpedoes." The Submarine Review, April 1996.[page needed]
- Newpower 2006, p. 151, stating, "The very next day, 10 April, USS Pompano encountered the Pearl Harbor veteran Shokaku and attacked with six torpedoes. En route to their target, three of the torpedoes exploded early, and two exploded close to the expected time. Lockwood knew from ULTRA that Shokaku survived the attack and although he credited Pompano with damaging the carrier rather than revealing ULTRA information, doubts began to surface in his mind concerning the magnetic exploder."
- Newpower 2006, p. 139
- Blair 1975, pp. 575–576 and 767–768
- Blair 1975, p. 274
- Blair 1975, p. 275
- Blair 1975, p. 276
- Blair 1975, pp. 131,197,273–275
- Blair 1975, p. 277
- Blair 1975, pp. 226–227
- Newpower 2006, p. 150
- Newpower 2006, pp. 150–151
- Newpower 2006, p. 151
- Newpower 2006, p. 151
- Newpower 2006, pp. 151–152
- Newpower 2006, p. 153
- Newpower 2006, p. 155
- Newpower 2006, p. 158
- Blair 1975, pp. 430–431
- Newpower 2006, p. 161
- Newpower 2006, p. 180
- Blair 1975, p. 439
- Blair 1975, p. 438
- Milford, Frederick J. (October 1996), "U. S. Navy Torpedoes. Part Two: The great torpedo scandal, 1941–43.", The Submarine Review, Archived from the original on October 25, 2009
- Kurak, Steve (September 1966). "The U. S. Navy's Torpedo Inventory". United States Naval Institute Proceedings.
- NavWeaps.com. United States of America Information on Torpedoes. Torpedo Nomenclature
- Blair, Clay, Jr. (1975), Silent Victory, Philadelphia: Lippincott, ISBN 0-553-01050-6
- Newpower, Anthony (2006), Iron Men and Tin Fish: The Race to Build a Better Torpedo during World War II, Praeger Security International, ISBN 0-275-99032-X
- Roscoe, Theodore (1967), Pig Boats: The True Story of the Fighting Submariners of World War II, New York: Bantam, OCLC 22066288. Originally published in 1949 as United States Submarine Operations in World War II; Bantam version is abridged
- Rowland, Buford; Boyd, William B. (1953), U.S. Navy Bureau of Ordnance in World War II, Bureau of Ordnance
- United States of America Torpedoes of World War II
- Wildenberg, Thomas; Polmar, Norman (2010), Ship Killer, Naval Institute Press, ISBN 978-1-59114-688-9
- US 5790405, Buchler, Robert J., "Method and apparatus for detecting circular torpedo runs", issued August 4, 1998, assigned to Litton Systems, Inc.
- Gannon, Robert (1996), Hellions of the Deep: The Development of American Torpedoes in World War II, Pennsylvania State University Press, ISBN 027101508X
- Matthews, David F. (26 February 2011), Mark XIV Torpedo Case Study (PDF), Monterey, CA: Naval Postgraduate School, NPS-AM-11-008 (DTIC A550699)
- Newpower, Anthony (2010), Iron Men and Tin Fish: The Race to Build a Better Torpedo During World War II, Annapolis, Md: Naval Institute Press, ISBN 978-1-59114-623-0
- Instructions for upkeep & operation of the mark VI mod. 1 exploder mechanism, Ordnance Pamphlet, Bureau of Ordnance, 1938, OCLC 51958048, OP 632
- Torpoedoes: Mark 14 and 23 Types, Ordnance Pamphlet, Bureau of Ordnance, 24 March 1945, OP 635
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