View source for Mark 14 torpedo

{{short description|US torpedo of WWII}}
{{Use American English|date=November 2024}}
{{Use dmy dates|date=November 2024}}
{{Infobox weapon
| name               = Mark 14 torpedo
| image              = Mark 14 torpedo side view and interior mechanisms, Torpedoes Mark 14 and 23 Types, OP 635, March 24 1945.jpg
| image_size         = 300
| caption            = Mark 14 torpedo side view and interior mechanisms, as published in a service manual
| origin             = United States
| type               = [[Anti-surface warfare|Anti-surface ship]] [[torpedo]]<ref name="navyhist">{{cite web |title=Torpedo History: Torpedo Mk14 |url=http://www.history.navy.mil/museums/keyport/html/part2.htm |access-date=13 June 2013 |archive-date=15 September 2014 |archive-url=https://web.archive.org/web/20140915054904/http://www.history.navy.mil/museums/keyport/html/part2.htm |url-status=dead }}</ref><!-- Also used against subs, & not strictly a dedicated type at the time of introduction -->
<!-- Type selection -->| is_ranged          = y
| is_explosive       = y
| is_missile         = y
<!-- Service history -->| service            = Unknown–1980
| used_by            = [[United States Navy]]
| wars               = [[World War II]]
<!-- Production history -->| designer           = [[Naval Torpedo Station]] [[Newport, Rhode Island]]<ref name="navyhist"/>
| design_date        = 1931<ref name="navyhist"/>
| manufacturer       = [[Naval Torpedo Station]] Newport, RI<ref name="navyhist"/><br />[[Torpedo Factory Art Center|Naval Torpedo Station Alexandria, VA]]<br />[[Keyport, Washington|Naval Torpedo Station Keyport, Washington]]<br />[[Naval Ordnance Station Forest Park|Naval Ordnance Plant Forest Park, IL]]
| unit_cost          = 
| production_date    = 1942-1945<ref name="hnsa">{{cite web |last=Jolie |first=E.W. |title=A Brief History of U.S. Navy Torpedo Development |url=http://www.maritime.org/doc/jolie/part1.htm |access-date=5 June 2013 |date=15 September 1978}}</ref>
| number             = 13,000<ref name="hnsa"/>
| variants           = <!-- General specifications -->
| spec_label         = 
| weight             = Mod.0: {{cvt|3000|lb|kg|sigfig=4}}
Mod.3: {{cvt|3061|lb|kg|sigfig=4}}
| length             = {{convert|20|ft|6|in|abbr=on}}
| part_length        = 
| width              = 
| height             = 
| diameter           = {{convert|21|in|abbr=on}}
| crew               = <!-- Ranged weapon specifications -->
| range              = {{convert|4500|yard|m}} at {{convert|46|kn|km/h}}<br />{{convert|9000|yard|m}} at {{convert|31|kn|km/h}}
| max_range          = <!-- Explosive specifications -->
| filling            = Mod.0 [[TNT]] Mod.3 [[Torpex]]
| filling_weight     = Mod.0: {{convert|507|lb|abbr=on}} Mod.3: {{convert|643|lb|abbr=on}}
| detonation         = Contact or [[magnetic pistol]]
| yield              = <!-- Vehicle/missile specifications -->
| engine             = [[Torpedo#Wet-heater|Wet-heater]] combustion / steam turbine with compressed air tank
| engine_power       = 
| pw_ratio           = 
| transmission       = 
| payload_capacity   = 
| propellant         = 180 proof ethanol blended with methanol or other denaturants<!-- Grider, IIRC, says it was in ''War Fish'', but I don't have it at hand, & Google Books doesn't offer a searchable... -->
| fuel_capacity      = 
| boost              = 
| speed              = {{convert|46|knots|km/h}}
| guidance           = [[Gyroscope]]
| steering           = 
| accuracy           = 
| launch_platform    = [[Submarine]]s
| transport          = 
}}
[[File:Mark XIV torpedo.JPG|thumb|right|A Mark 14 torpedo on display at [[Fisherman's Wharf, San Francisco|Fisherman's Wharf]] in [[San Francisco]]]]
[[File:Cleveland August 2015 37 (Mark 14 torpedo).jpg|thumb|right|A Mark 14 torpedo on display in [[Cleveland]], near {{USS|Cod|SS-224|6}}]]

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 torpedo|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.<ref>{{Cite web |title=The Tragedy of the Mark XIV Torpedo in World War II |url=https://militaryhistoryonline.com/WWII/MarkXIVTorpedo |access-date=2024-04-24 |website=militaryhistoryonline.com}}</ref> After the fixes, the Mark&nbsp;14 played a major role in the devastating blow U.S.&nbsp;Navy submarines dealt to the Japanese naval and merchant marine forces during the [[Pacific War]].

By the end of World War II, the Mark&nbsp;14 torpedo was a reliable weapon ultimately remaining in service for almost 40&nbsp;years in the U.S.&nbsp;Navy, and even longer with other navies.

== Development ==
[[File:Torpedo Exploder Mark 6 NH-88457.jpg|thumb|right|The only live fire test of the magnetic influence exploder before the war occurred in 1926.  In this picture of the first shot, the Mark 10 torpedo with the experimental exploder ran underneath the target without exploding.  The second test shot exploded under the target submarine and sank it.  Although the Navy conducted other tests, those tests were nondestructive: the torpedoes would not be damaged by the tests.]]

The design of the Mark 14 started in January 1931; the Navy allocated $143,000 for its development.<ref>{{harvnb|Wildenberg|Polmar|2010|p=60}}</ref> The Mark 14 was to serve in the new "fleet" submarines and replace the [[Mark 10 torpedo|Mark 10]] which had been in service since [[World War I]] and was standard in the older [[United States R class submarine|R-]] and [[United States S class submarine|S-boat]]s. Although the same diameter, the Mark&nbsp;14 was longer, at {{convert|20|ft|6|in|abbr=on}}, and therefore incompatible with older submarines' {{convert|15|ft|3|in|abbr=on}} [[torpedo tube]]s. Later in the war, the [[Bureau of Ordnance]] (BuOrd) stopped producing Mark 10s for the S-boats and provided a shortened Mark 14.<ref name="Rowland 1953 95">{{harvnb|Rowland|Boyd|1953|p=95}}</ref>

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 submarine's torpedo tubes: 21&nbsp;inches in diameter and a certain maximum 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 {{convert|46|kn|km/h}} compared to the Mark 10 Mod 0's {{convert|30|kn|km/h}}.<ref>{{harvnb|Wildenberg|Polmar|2010|pp=218, 219}}</ref> 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 &mdash; the depth would not stabilize quickly; the Mark 14 depth stabilization was improved.<!-- ref described Uhlan control in Mark 10 was limited to 1 degree or 1 percent.-->{{Citation needed|date=October 2016}}

The design for the [[Mark 6 exploder]] used in the Mark 14 torpedo had started at the [[Naval Torpedo Station]] (NTS), [[Newport, Rhode Island|Newport]], in 1922. Ship armor was improving with innovations such as [[torpedo belt]]s and [[Anti-torpedo bulge|torpedo blisters (bulges)]]. To circumvent these measures, torpedoes needed larger warheads or new technology.  One option would use a fairly small warhead<ref name="Blair, p.278">{{Harvnb|Blair|1975|p=278}}</ref><ref>{{harvnb|Rowland|Boyd|1953|p=109}} argues small explosive is enough</ref> but was intended to explode beneath the [[keel]] where there was no armor.<ref name="Blair, p.54"/> This technology required the sophisticated new Mark 6 [[magnetic influence]] [[exploder]], which was similar to the British Duplex<ref>Fitzsimons, Bernard, general editor. ''The Illustrated Encyclopedia of 20th Century Weapons and Warfare'' (London: Phoebus Publishing, 1978), Volume 8, p.807, "Duplex"</ref> and German<ref>Dönitz, ''Memoir''.</ref> models, all inspired by German [[magnetic mine]]s of World War I.<ref name="Blair, p.54">{{Harvnb|Blair|1975|p=54}}</ref> The Mark 14 shared this exploder with the concurrently-designed surface ship [[Mark 15 torpedo]].<ref name="navyhist"/>

The Mark 6 exploder, designated Project G53,<ref name="Blair, p.55">{{Harvnb|Blair|1975|p=55}}</ref> was developed "behind the tightest veil of secrecy the Navy had ever created."<ref name="Blair, p.55"/> Exploders were tested at the Newport lab and in a small field test aboard {{USS|Raleigh|CL-7|6}}.<ref>{{harvnb|Wildenberg|Polmar|2010|p=65}}</ref>  At [[Ralph Waldo Christie|Ralph Christie's]] urging, equatorial tests were later conducted with {{USS|Indianapolis|CA-35|6}}, which fired one hundred trial shots between 10°N and 10°S<ref name="Blair 1975 61–62">{{Harvnb|Blair|1975|pp=61–62}}</ref> and collected 7000&nbsp;readings.<ref name="Blair, p.62">{{Harvnb|Blair|1975|p=62}}</ref> 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.<ref name="Blair 1975 61–62"/> Inexplicably, no live fire trials were ever done with production units. [[Chief of Naval Operations]] [[William V. Pratt]] offered the [[Hulk (ship type)|hulk]] of {{sclass|O'Brien|destroyer|0}}<ref>Fitzsimons, Volume 5, p.541, table.</ref> [[destroyer]] {{USS|Ericsson|DD-56|2}},<ref name="Blair, p.62"/> but prohibited the use of a live warhead, and insisted the BuOrd pay the cost of refloating her if she was hit in error.<ref name="Blair, p.62"/> These were strange restrictions, as ''Ericsson'' was due to be scrapped.<ref>Between 1934 and 1936. Fitzsimons, Volume 5, p.542, "''Cassin''".</ref> BuOrd declined.<ref name="Blair, p.62"/> A service manual for the exploder "was written—but, for security reasons, not printed—and locked in a safe."<ref name="Blair, p.62"/>

Torpedoes were sophisticated and expensive. The cost of a torpedo in 1931 was about $10,000 ({{Inflation|US|10000|1931|r=-3|fmt=eq}}).<ref>{{harvnb|Wildenberg|Polmar|2010|p=60}}; stating that $803,000 was allocated for the production of 76 torpedoes.</ref>  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. This sometimes led to problems: a contact exploder that worked reliably at {{convert|30|kn|km/h}} failed at {{convert|46|kn|km/h}}. In addition, the Navy had limited experience in using torpedoes in combat.<ref>{{harvnb|Wildenberg|Polmar|2010|p=63}}</ref>

== Supply and production ==
[[File:Torpedo production US WWII.jpg|thumb|left|United States torpedo production during World War II]]
The U.S. 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.<ref>{{harvnb|Wildenberg|Polmar|2010|p=48}}</ref> During World War I, the Navy had almost 300 destroyers that each had 12 torpedo tubes.<ref>{{harvnb|Wildenberg|Polmar|2010|p=52}}</ref> 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 U.S.<ref>{{harvnb|Wildenberg|Polmar|2010|p=53}}</ref> When war was declared on Germany, another 2,000 torpedoes were ordered. 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.<ref>{{harvnb|Wildenberg|Polmar|2010|p=55}}</ref>  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 shuttered 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&nbsp;14 tests.

The Navy had not learned from the torpedo supply lessons of WWI. Looking back in 1953, the Bureau of Ordnance 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 was exposed. There were simply no realistic plans available for providing the weapon in adequate quantity."<ref>{{harvnb|Rowland|Boyd|1953|p=91}}</ref> There was little interest in torpedo production until 1933 when the [[Vinson&ndash;Trammell Act|Vinson Shipbuilding Program]] recognized the need for torpedoes to fill the torpedo tubes on its newly constructed ships.<ref>{{harvnb|Rowland|Boyd|1953|p=124}}</ref> Consequently, Newport received new production equipment and an increased budget.<ref name="Rowland 1953 125">{{harvnb|Rowland|Boyd|1953|p=125}}</ref> NTS produced only 1½&nbsp;torpedoes a day in 1937, despite having three shifts of three thousand workers<ref name="Blair, p.69">{{Harvnb|Blair|1975|p=69}}</ref> working around the clock.<ref name="Blair, p.281"/> Production facilities were at capacity and there was no room for expansion.<ref name="Blair, p.69"/>

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.<ref name="Rowland 1953 125"/> 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.<ref name="Rowland 1953 125"/> 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."<ref name="Rowland 1953 126">{{harvnb|Rowland|Boyd|1953|p=126}}</ref> By the fall of 1941, Alexandria had been reopened.<ref>{{harvnb|Wildenberg|Polmar|2010|p=69}}</ref> 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.<ref name="Rowland 1953 126"/> The Navy contracted with the [[American Can Company]] to produce torpedoes.

The short supply of Mark 14 torpedoes was compounded by a 10 December 1941 Japanese air raid on [[Cavite Navy Yard]] in the [[Philippines]]. The attack destroyed 233 Mark 14 torpedoes.<ref>{{harvnb|Wildenberg|Polmar|2010|p=105}}</ref>

After the U.S. entered the war, the contract with American Can was expanded and [[Pontiac (automobile)|Pontiac Motor Company]], [[International Harvester]], E. W. Bliss Company, and [[Precision Manufacturing Co.]] were retained as contractors. In May 1942, [[Westinghouse Electric Corporation]] was asked to build an electric torpedo (which became the [[Mark 18 torpedo]]).<ref>{{harvnb|Rowland|Boyd|1953|p=127}}</ref>

Only 2,000 submarine torpedoes were built by all three Navy factories (Newport, Alexandria, and Keyport) during 1942.<ref name="Blair, p.69"/><ref name="Blair, p.281">{{Harvnb|Blair|1975|p=281}}</ref> This exacerbated torpedo shortages; the Pacific Fleet Submarine Force had fired 1,442 torpedoes since war began.<ref>{{Harvnb|Blair|1975|p=553}}</ref> <!--(Many of these would be [[Mark 10 torpedo|Mark 10]]s from prewar stockpiles, but most would continue to be Mark&nbsp;14s. In addition, there were destroyer [[M torpedo|Mark 15]]s being expended at a fairly prodigious rate.)--> In the words of BuOrd's own account of WWII, "Until the spring of 1945, supply was a problem" for the Mark 14 torpedo.<ref name="Rowland 1953 96">{{harvnb|Rowland|Boyd|1953|p=96}}</ref>

The torpedo shortage at the start of the war also meant that commanders did not want to waste torpedoes on testing.

== Controversy ==
[[File:Captain Theodore Westfall and Captain Carl Bushnell of the Bureau of Ordnance, inspect the Naval Torpedo Station's first Mk 14, 1943.jpg|thumb|right|Captain Theodore Westfall, NTS CO and Captain Carl Bushnell of the Bureau of Ordnance, inspect a Mark 14 torpedo at the Naval Torpedo Station, Keyport, Washington, 1943<ref>{{cite book |last=Poole |first=Lisa |url=http://www.maritime.org/doc/torpedotown/chap5.htm |title=Torpedo Town U.S.A |publisher=Diamond Anniversary Publishing |year=1989 |isbn=0-9621829-0-7}}</ref>]]
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 uncovered 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.<ref>{{harvnb|Rowland|Boyd|1953|p=96}} stating, "what was worse, however, was the diabolical way in which each defect concealed another."</ref> Much of the blame commonly attached to the Mark&nbsp;14 correctly belongs to the Mark&nbsp;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) yet failed to explode.<ref name="Morison IV">{{citation |last=Morison |first=Samuel E. |author-link=Samuel Eliot Morison |title=History of United States Naval Operations in World War II |volume=IV |pages=passim}}</ref>

Responsibility lies with the Bureau of Ordnance, which specified an unrealistically rigid magnetic exploder sensitivity setting and oversaw the feeble testing program. Its small 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.<ref name="Morison IV" /> 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.<ref name="Roscoe, 1967">{{Harvnb|Roscoe|1967}}</ref> The Bureau of Ordnance failed to assign a second naval facility for testing, and failed to give Newport adequate direction.

== Problems ==
The Mark 14 torpedo had four major flaws.
* It tended to run about {{convert|10|ft|m|sigfig=1}} deeper than set.
* The [[Magnetic pistol|magnetic exploder]] often caused premature detonation.
* The contact exploder often failed to detonate 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.<ref name="circular">{{harvtxt|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|SS-306|6}} was sunk by a Mark 18 (not a Mark 14); {{USS|Tullibee|SS-284|6}} may have been sunk by a Mark 18. {{USS|Sargo|SS-188|6}} had a circular run because the gyro was not installed.</ref>

Some of these flaws had the unfortunate property of masking or explaining other flaws.  Skippers would fire torpedoes and expect the magnetic influence exploder to sink the target ship. When the torpedoes did not explode, they started to believe the magnetic influence exploder did not work.  Against orders, some submariners disabled the magnetic influence feature of the Mark&nbsp;6 exploder,{{Citation needed|date=November 2016}} suspecting it was faulty, and went for contact exploder hits; such efforts would confuse the issues. Looking back in 1953, the BuOrd speculated, "Many shots planned for impact against the side of a ship missed because of deep running, yet damaged the enemy due to the magnetic influence feature of the Mark 6."<ref>{{harvnb|Rowland|Boyd|1953|p=103}}</ref> When later tests discovered the torpedoes ran deeper than set, the submarine command then believed that the torpedoes ran so deeply that the magnetic influence exploder could not sense the target ship; that the failure to explode had been due entirely to the depth setting and that nothing was wrong with the magnetic influence exploder.<!-- Lockwood believed his skippers, did his fishing net depth test, and though the issue was over.-->  When the depth issue was fixed, the magnetic influence exploder's premature detonation made it seem like the exploder was working but little damage would be done to the target ship. It was only after the magnetic influence feature was deactivated that problems with the contact exploder would be discernible.

=== Running too deep ===
On 24 December 1941, during a war patrol, [[Commander]] [[Tyrell D. Jacobs]] in {{USS|Sargo|SS-188|2}} fired eight torpedoes at two different ships with no results. When two additional merchantmen came in view, Jacobs took extra care to set up his torpedo shots. He pursued the targets for fifty-seven minutes<ref name="Blair, p.141">{{Harvnb|Blair|1975|p=141}}</ref> and made certain the [[Torpedo Data Computer|TDC]] bearings matched perfectly before firing two torpedoes at each ship from an average range of {{convert|1000|yd|abbr=on}}. The shots should have hit, but all failed to explode.<ref name="Blair, p.140">{{Harvnb|Blair|1975|p=140}}</ref>

A few days later, he discovered the torpedoes were running too deep, and corrected the problem,<ref>{{Harvnb|Blair|1975|p=141}}. BuOrd would wait months to do the same.</ref> Jacobs detected a big, slow tanker. Again, his approach was meticulous, firing one torpedo at a close range of {{convert|1200|yd|abbr=on}}. It missed. Exasperated, Jacobs broke radio silence to question the Mark&nbsp;14's reliability.<ref>Blair, pp.140-141 & 169</ref>

A similar experience happened to [[List of military figures by nickname#P|Pete Ferrall]] in {{USS|Seadragon|SS-194|2}}, who fired eight torpedoes for only one hit and began to suspect the Mark&nbsp;14 was faulty.<ref>{{Harvnb|Blair|1975|p=171}}</ref>

==== Lockwood's depth tests ====
Shortly after replacing [[John E. Wilkes]] as Commander of Southwest Pacific submarines in [[Fremantle, Western Australia]],<ref name="Blair, p.274">{{Harvnb|Blair|1975|p=274}}</ref> newly minted [[Rear Admiral]]<ref name="Blair, p.274"/> [[Charles A. Lockwood]] ordered a historic net test at [[Frenchman Bay (Australia)|Frenchman Bay]], Albany on 20&nbsp;June 1942.<ref name="Blair, p.275">{{Harvnb|Blair|1975|p=275}}</ref> Eight hundred torpedoes had already been fired in combat,<ref name="Blair, p.275"/> more than a year's production from NTS.

[[James W. Coe|Jim Coe]]'s {{USS|Skipjack|SS-184|2}} fired a single torpedo with an exercise head from a distance of {{convert|850|yd}}. Despite being set for a depth of {{convert|10|ft|abbr=on|sigfig=1}}, the torpedo pierced the net at a depth of {{convert|25|ft|abbr=on}}.<ref name="Blair, p.276">{{Harvnb|Blair|1975|p=276}}</ref> [[James Fife, Jr.]] (formerly [[Chief of staff|Chief of Staff]] to <small>COMSUBAS</small> Wilkes, whom Lockwood was replacing)<ref>{{Harvnb|Blair|1975|pp=131,197,273–275}}</ref> followed up the next day with two more test shots; Fife concluded the torpedoes ran an average {{convert|11|ft|abbr=on}} deeper than the depth at which they were set. BuOrd was not amused.<ref name="Blair, p.276"/> Neither was the [[Chief of Naval Operations|CNO]], Admiral [[Ernest J. King]], who "lit a blowtorch under the Bureau of Ordnance".<ref>{{Harvnb|Blair|1975|p=277}}</ref> The fact that destroyers' Mark 15s were suffering the same failures may have had something to do with it as well. On 1&nbsp;August 1942, BuOrd finally conceded the Mark&nbsp;14 ran deep, and six weeks later, "that its depth-control mechanism had been 'improperly designed and tested'{{-"}}.<ref name="Blair, p.278"/>

==== Depth explanation ====
<!-- Measurements to find depth. Problems with fishing nets. After discovery, BuOrd knew there was a problem but did not understand the mechanism for quite some time. -->
The Mark 14 torpedo tended to run some {{convert|10|ft|m|sigfig=1}} too deep for several reasons. The first was that it was tested with an exercise warhead that was more buoyant than the tactical warshot warhead; that was a precaution made to avoid losing an expensive torpedo. A light exercise head made the torpedo positively buoyant, so it would float to the surface at the end of its run. The live warhead contained more mass, so it reached equilibrium at a lower depth.<ref>{{cite book |url=https://books.google.com/books?id=nThUZVcJo60C&pg=PT88 |page=88 |last=Scott |first=James |title=The War Below: The Story of Three Submarines That Battled Japan |publisher=Simon and Schuster |year=2013 |isbn=978-1439176856}}</ref> Also, the depth mechanism was designed prior to the warhead's explosive charge being increased, making the torpedo even heavier overall. "Testing conditions became more and more unrealistic, obscuring the effect of the heavier warhead on depth performance."<ref>{{harvnb|Rowland|Boyd|1953|p=98}}</ref> Furthermore, the depth testing device used by NTS to verify the torpedo's running depth (the depth and roll recorder) had the same measuring port placement error as the Mark 14's depth control port, so both were off by the same amount in the same direction and gave the impression that the torpedo was running at the desired depth when it was actually much deeper.<ref name="depth-roll">{{harvnb|Rowland|Boyd|1953|p=97}}</ref> After hearing of the deep-running torpedo problem, most submarine skippers simply set their torpedoes' running depth to zero,<ref name="historynet.com">{{cite journal |last=Shireman |first=Douglas A. |title=U.S. Torpedo Troubles During World War II |date=February 1998 |journal=World War II |url=http://www.historynet.com/us-torpedo-troubles-during-world-war-ii.htm }}</ref> which risked the torpedo broaching the surface.

Torpedo depth is a [[Control theory|control problem]]; good depth control requires more than just measuring the torpedo's depth.<!-- pulling loops at significant depth; torpedo will be pitched up when too deep; at the right depth, its elevators (depth rudders) will go to zero but the torpedo will continue to rise. The torpedo needs to start pitching down as it nears the set 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 Torpedo Works|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."<ref>{{harvnb|Newpower|2006|p=12}} citing {{citation |first=Edwyn |last=Gray |title=The Devil's Device: Robert Whitehead and the History of the Torpedo |location=Annapolis, MD |publisher=U.S. Naval Institute |date=1991 |page=33 |ref=none}}.</ref> This development (known as "The Secret") was around 1868.<ref>{{citation |last=Sleeman |first=C. W. |title=Torpedoes and Torpedo Warfare |date=1880 |location=Portsmouth |publisher=Griffin & Co. |pages=137&ndash;138 |url=https://archive.org/stream/torpedoestorpedo00sleerich#page/136/mode/2up/search/depth |quote=which constitutes what is termed as the secret of the fish torpedo. |ref=none}}</ref>

Depth control in early torpedoes such as the Mark 10 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.<ref name="Rowland 1953 96"/> For example, to change depth by {{convert|30|ft|m|sigfig=1}} on a 1° slope takes a horizontal run of about {{convert|1800|ft|m}}. The improved Uhlan mechanism (Uhlan gear) for depth control had much faster depth stabilization and had been introduced in the Mark 11 torpedo.<ref>{{harvnb|Wildenberg|Polmar|2010|p=58}}</ref><!-- Confusion here. Uhlan uses a pendulum, so it may just be a dynamic range issue. Cannot find a description of early depth control. -->

When the Uhlan gear was incorporated in the Mark 14 design, the pressure sensing port for the depth mechanism was moved from its position on the cylindrical body to the cone-shaped tail section; the designers did not realize that move would affect the pressure readings.<ref>{{harvnb|Rowland|Boyd|1953|pp=96&ndash;97}}</ref> This repositioning meant that when the torpedo was moving, a hydrodynamic flow effect created a substantially lower pressure at the port than hydrostatic depth pressure.  The torpedo's depth control engine therefore thought the torpedo was at too shallow a depth and responded by trimming the torpedo to run deeper. A simple laboratory test (such as immersing a non-moving torpedo in a pool of static water) would not be subject to the flow-induced pressure change and would show the torpedo trimmed at the desired depth. Dynamic tests using exercise heads with depth and roll recorders would have shown the depth problem, but the depth measuring port suffered from the same placement problem and gave consistent (though incorrect) measurements.<ref name="depth-roll"/> 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.<ref>"The Great Torpedo Scandal of 1941 - 1943", The Submarine Review, October 1996</ref>

=== Magnetic influence exploder and premature explosions ===
[[File:Torpedo exploder Mark 6 Mod 1.jpg|right|thumb|Mark 6 Mod 1 exploder used early in the war.<ref>{{Citation |last=Patrick |first=John |title=The Hard Lessons of World War II Torpedo Failures |journal=Undersea Warfare |date=Winter 2012 |issue=47 |url=http://www.public.navy.mil/subfor/underseawarfaremagazine/issues/archives/issue_47/torpedo_2.html |access-date=2013-06-22 |archive-url=https://web.archive.org/web/20141013151521/http://www.public.navy.mil/subfor/underseawarfaremagazine/issues/archives/issue_47/torpedo_2.html |archive-date=2014-10-13 |url-status=dead }}</ref> Later on it was replaced with the Mark 6 Mod 5.]]

By August 1942, the faulty running depth situation was resolved, and submarines were getting more hits with the Mark&nbsp;14. However, curing the deep-running problem caused more prematures and duds even as more hits were being achieved. The number of sinkings did not rise.<ref>{{Harvnb|Blair|1975|p=292}}</ref>

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 Henry English|Robert H. English]] (then <small>COMSUBPAC</small>),<ref>{{Harvnb|Blair|1975|pp=226–227}}</ref> who both refused to believe the exploder could also be defective.<ref name="Blair, p.278"/>  In August 1942, the submarine commands believed mistakenly that the torpedo reliability problem was solved.

The skippers, however, continued to report problems with the Mark 14. Suspicion about the magnetic influence exploder grew.

[[Lieutenant Commander]] [[John Addison Scott|John A. Scott]] in {{USS|Tunny|SS-282|2}} on 9&nbsp;April 1943 found himself in an ideal position to attack aircraft carriers {{ship|Japanese aircraft carrier|Hiyō||2}}, {{ship|Japanese aircraft carrier|Junyo||2}}, and {{ship|Japanese aircraft carrier|Taiyo||2}}. From only {{convert|880|yd|abbr=on}}, 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;<ref name="Roscoe, 1967"/> the torpedoes had run true but the magnetic feature had triggered and exploded the warheads too early.<ref>{{Harvnb|Blair|1975|p=413}}</ref>

On 10 April, {{USS|Pompano|SS-181|6}} attacked Japanese aircraft carrier {{ship|Japanese aircraft carrier|Shōkaku||2}} by firing six torpedoes.  There were at least three premature explosions, and the aircraft carrier was not damaged.<ref name="Newpower 2006 151">{{harvnb|Newpower|2006|p=151}}</ref>

On 10 April 1943, Bureau of Ordnance Chief Admiral Blandy wrote Lockwood that the Mark 14 was likely to explode prematurely at shallow depths.<ref name="Newpower 2006 151"/>  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 {{convert|450|yd|m}} was too short; an arming distance of {{convert|700|yd|m}} 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.<ref>{{harvnb|Newpower|2006|pp=151&ndash;152}}</ref>

On 8 May 1943, Lockwood made a list of torpedo failures gleaned from ULTRA intercepts.<ref>{{harvnb|Newpower|2006|p=153}}</ref>

On 10 June 1943, {{USS|Trigger|SS-237|6}} fired six torpedoes from {{convert|1200|yd|m}} at the aircraft carrier ''Hiyō''. Two torpedoes missed, one exploded prematurely, one was a dud, and two hit.  The carrier was damaged but made it home.<ref>{{harvnb|Newpower|2006|p=155}}</ref>

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)<ref>Milford, Frederick J. "U. S. Navy Torpedoes." ''The Submarine Review'', April 1996.{{page needed|date=August 2015}}</ref> were conducted, differed from the areas where the fighting was taking place.

Submarine skippers believed that about 10 percent of their torpedoes prematurely exploded; BuOrd statistics had the premature explosions at 2 percent.<ref>{{harvnb|Rowland|Boyd|1953|p=104}}</ref>

==== Deactivation ====
At [[Pearl Harbor]], despite nearly all his skippers' suspicions about the torpedoes,<ref>{{Harvnb|Blair|1975|p=216}}</ref> Rear Admiral [[Thomas Withers, Jr.]] refused to deactivate the torpedo's Mark&nbsp;6 exploder, arguing torpedo shortages stemming from inadequate production at NTS made it impossible.<ref>{{Harvnb|Blair|1975|p=206}}</ref> 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.<ref>{{Harvnb|Blair|1975|p=206}}. This helps explain why U.S. tonnage claims per ship were routinely about a third higher than actual sinkings.</ref>

<!-- Lockwood actually compiled a list of failures that showed MI was causing prematures. Blair may not have been privy to that info. There was an extensive discussion with Blandy and a draft letter to the fleet about MI's limitations. Lockwood thought the letter introduced too many considerations for combat action and decided to pull the plug on MI. -->
Only in May 1943, after the most famous skipper in the Sub Force, [[Dudley W. Morton|Dudley W. "Mush" Morton]], returned having failed to inflict any damage, did Lockwood, [[ComSubPac|Commander Submarine Force Pacific]] (<small>COMSUBPAC</small>), accept the Mark&nbsp;6 should be deactivated. It took a commander of Morton's stature to challenge the Navy senior command and move them into action, even at the risk of Morton's career.<ref>{{cite web | url=http://www.emackinnon.com/wahoo-anecdotes.html | title=USS Wahoo Anecdotes| access-date=2021-02-14 }}</ref>

Nonetheless, Lockwood waited to see if BuOrd commander Admiral [[William H. P. Blandy|William "Spike" Blandy]] might yet find a fix for the problem.<ref>{{Harvnb|Blair|1975|p=427}}</ref> The BuOrd 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.<ref>{{Harvnb|Blair|1975|pp=169–170}}</ref>
In late June 1943, Lockwood (by then <small>COMSUBPAC</small>) 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.<ref>{{harvnb|Newpower|2006|p=158}}</ref>

Rear Admiral [[Ralph Waldo 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 (command)|South West Pacific Area]] and not in Nimitz' chain of command. Christie insisted his area's submarines continue to use the magnetic exploder.<ref>{{harvnb|Blair|1975|pp=430–431}}</ref> 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.<ref>{{harvnb|Newpower|2006|p=161}}</ref>

==== Premature explosion explanation ====
{{More citations needed section|date=May 2019}}
[[File:FiringGeometry.png|thumb|upright=2.0|A torpedo may take a long time before it settles on its final course. If the torpedo direction is still changing when the torpedo arms, it may set off the magnetic influence exploder.]]

In 1939, before the war started for the U.S., BuOrd knew the magnetic influence exploder was suffering from unexplained premature detonations:<ref>{{harvnb|Rowland|Boyd|1953|p=102}}</ref>
: Evidence of that fact came in 1939, when Newport reported to the Bureau that the exploder was giving unexplained prematures. Admiral [[William R. Furlong|Furlong]] arranged for a physicist to visit the station and investigate the failures. For approximately a week, the scientist and his assistants worked with the device. Four sources of prematures were uncovered. Even more significant, the investigator reported to the Bureau that the responsible engineers at Newport were not employing proper tests on the Mark 6. Corrective steps were ordered by the Chief, but subsequent events proved that the remedial action, like the original tests, was inadequate.

There were two common types of premature explosions.  In the first, the warhead exploded just as it armed{{Citation needed|reason=There needs to be a source specifically stating that this was a common type of premature explosion because this is a significant claim to make|date=May 2019}}.  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{{Example needed |s|date=May 2019}}. Sometimes the submarine command would hear about these premature explosions from intercepted enemy communications.<ref>{{harvnb|Newpower|2006|p=151}}, stating, "The very next day, 10 April, {{USS|Pompano|SS-181|6}} 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 (cryptography)|ULTRA]] that ''Shokaku'' survived the attack and although he credited {{USS|Pompano|SS-181|2}} with damaging the carrier rather than revealing ULTRA information, doubts began to surface in his mind concerning the magnetic exploder."</ref>

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.<!-- arming distance 450 yards (see above); reach is 80 yards at tube depth of 20 ft; turning radius is 215 yards. 80 + 215 * pi / 2 is close (418 yd). --> As the warhead approached the target, it could sense a change due to the ship's effect 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.<ref>{{harvnb|Newpower|2006|p=139}}</ref>

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.

=== Contact exploder ===
[[File:Torpedo Exploder Mark 6 NH Drawing.png|thumb|Detail of Mark 6 exploder.  For contact operation, the collision of the torpedo with the target ship would move the ''firing ring'' and release the ''firing pin stem''. The ''firing pin stem'' would then move vertically (powered by the ''firing spring'') and detonate the [[tetryl]] [[booster charge]].  The mechanism worked for low-speed torpedoes,<ref>{{harvnb|Newpower|2006|p=180}}</ref> but for the high-speed Mark 14 torpedo, the same impact deceleration that caused the ''firing ring'' to move was also large enough to cause the ''firing pin stem'' to bind and fail to detonate the booster.]]

Inactivation of the magnetic influence feature stopped all the premature explosions.<ref>{{harvnb|Rowland|Boyd|1953|p=106}}, "when inactivation stopped prematures altogether, the full extent of outright duds was exposed."</ref>

Early reports of torpedo action included some dud hits, heard as a dull clang. In a few instances, Mark&nbsp;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. The experience of Lawrence R. Daspit in {{USS|Tinosa|SS-283|2}}, firing nine torpedoes at a perfect [[abeam]] firing position, 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.{{citation needed|date=February 2023}}

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 carefully documented his efforts to sink 19,000-ton [[Factory ship|whale factory ship]] ''[[Tonan Maru No. 3]]'' on 24&nbsp;July 1943. He fired four torpedoes from {{convert|4000|yd|abbr=on}}; 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, {{convert|875|yd|abbr=on}} square off the target's beam, where he fired nine more Mark&nbsp;14s and observed all with his periscope (despite the Japanese firing at it). All were duds.<ref>When he returned, Daspit was livid.{{Harvnb|Blair|1975|pp=435–437}}</ref> Daspit, suspicious by now he was working with a faulty production run of Mark&nbsp;14s, saved his last remaining torpedo to be analyzed by experts back at base. Nothing out of the ordinary was found.<ref name="Roscoe, 1967"/>

==== Lockwood's drop tests ====
Daspit's cruise raised enough of an issue that tests were carried out by <small>COMSUBPAC</small>'s gunnery and torpedo officer, [[Arthur Howard Taylor|Art Taylor]]. Taylor, [[Charles Momsen|"Swede" Momsen]], and others fired warshots into the cliffs of [[Kahoolawe]], beginning 31&nbsp;August 1943.  Additional trials, supervised by Taylor, used a crane to drop warheads filled with sand instead of high explosive from a height of {{convert|90|ft}} (the height was chosen so the velocity at impact would match the torpedo's running speed of {{convert|46|kn|km/h}}). 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<ref name="Blair, p.439">{{Harvnb|Blair|1975|p=439}}</ref> (which cut the number of duds in half),<ref name="Blair, p.438">{{Harvnb|Blair|1975|p=438}}</ref> until a permanent solution could be found.

==== Contact exploder explanation ====
The Mark 6's contact exploder mechanism descended from the Mark 3 contact exploder. Both exploders had the unusual feature that the firing pin's travel was perpendicular to the torpedo's travel, so the firing pin would be subject to side loading when the torpedo struck its target. The Mark 3 exploder was designed when torpedo speeds were much slower (the Mark 10 torpedo's speed was {{convert|30|kn|km/h}}), but even then the Mark 3 prototypes had problems with the firing pin binding during the high deceleration when the torpedo collided with the target. The solution was to use a stronger firing spring to overcome the binding.<ref>{{harvnb|Rowland|Boyd|1953|pp=107,108}}</ref> The Mark 14 torpedo had a much higher speed of {{convert|46|kn|km/h}}, so it would see significantly higher deceleration, but BuOrd apparently just assumed the contact exploder would work at the higher speed. There were no live-fire tests of the Mark 14 torpedo, so there were no-live fire tests of its contact exploder. If BuOrd had tried some live-fire tests of the contact exploder during peacetime, it probably would have experienced some duds and rediscovered the binding problem.

Pearl Harbor made working exploders by using lighter weight aluminum parts. Reducing the mass reduces the binding friction.<!-- F=ma --> BuOrd suggested using a stiffer spring, the fix that had worked decades before.<ref>{{harvnb|Rowland|Boyd|1953|p=108}}</ref> In the end, BuOrd adopted a ball switch and electric detonator rather than using a firing pin mechanism.<!-- somewhere, the anti-countermining mechanism was determined to be faulty. See Rowland Boyd 1953 p=104, Lockwood thought Mark 6 was a Rube Goldberg device. -->

In September 1943, the first torpedoes with new contact pistols were sent to war.<ref>{{Citation|url=http://www.geocities.com/Pentagon/1592/ustorp2.htm |last=Milford |first=Frederick J. |title=U. S. Navy Torpedoes. Part Two: The great torpedo scandal, 1941–43. |journal=The Submarine Review |date=October 1996 |url-status=dead |archive-url=https://web.archive.org/web/20091023091106/http://geocities.com/Pentagon/1592/ustorp2.htm |archive-date=23 October 2009 }}</ref> "After twenty-one months of war, the three major defects of the Mark&nbsp;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."<ref name="Blair, p.439"/>

=== Circular runs ===
There were numerous reports of the Mark 14 running erratically and circling back on the firing boat. {{USS|Grunion||2}} is thought to have been sunk by a circular-running Mark 14 hitting the periscope tower without exploding, and jamming the diving controls at full emergency dive position.<ref name=stevens>Peter F. Stevens. ''Fatal Dive: Solving the World War II Mystery of the USS Grunion'', Regnery History, 2012</ref> A circular run sank the submarine {{USS|Tullibee|SS-284|2}}, but it may not have been a Mark 14.<ref name="circular"/><ref>{{Harvnb|Blair|1975|pp=575–576 and 767–768}}</ref> Likewise, ''Sargo'' was almost sunk by a circular run, but the circular run happened because the gyro had not been installed.<ref name="circular"/> The subsequent Mark 18 torpedo was no better, sinking {{USS|Tang|SS-306|2}}. The surface-launched Mark 15 torpedo had collars to prevent circular runs, but the Mark&nbsp;14 was never given this feature.

== Resolution ==
[[File:USS Pampanito after torpedo room 2.JPG|thumb|Two Mark 14 torpedoes stored in the aft torpedo room of the [[museum ship]] {{USS|Pampanito|SS-383|6}}]]

Once remedied, sinkings of enemy ships rose noticeably. By the end of World War II the Mark&nbsp;14 torpedo had become a much more reliable weapon. Lessons learned allowed surface ships such as destroyers to remedy the failings of the Mark&nbsp;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 torpedo|Mark 16]] with a pattern-running option. The Mark&nbsp;16 became the standard United States post-war anti-shipping torpedo, despite the large remaining inventory of Mark&nbsp;14 torpedoes.<ref>{{cite journal |last=Kurak|first=Steve |title=The U. S. Navy's Torpedo Inventory |journal=United States Naval Institute Proceedings |date=September 1966}}</ref>

== Nomenclature ==
Official U.S. 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]].<ref>{{Cite web |url=http://www.navweaps.com/Weapons/WTUS_Notes.htm |title=NavWeaps.com. United States of America Information on Torpedoes. ''Torpedo Nomenclature'' |access-date=2008-05-28 |archive-date=2008-07-27 |archive-url=https://web.archive.org/web/20080727023653/http://www.navweaps.com/Weapons/WTUS_Notes.htm |url-status=dead }}</ref> However, many instances exist of the Mark&nbsp;14 being referred to as the "Mark&nbsp;XIV" in official documentation and reports as well as accounts by historians and observers.{{citation needed|date=November 2024}}

== Characteristics ==
{{Unreferenced section|date=May 2019}}
* Function: Submarine launched anti-ship torpedo
* Powerplant: [[Torpedo#Wet-heater|Wet-heater]] combustion / [[steam turbine]] with compressed air tank
* Fuel: 180 proof [[Ethanol]] blended with [[methanol]] or other denaturants{{citation needed|date=December 2016}}
* Length: {{convert|20|ft|6|in|abbr=on}}
* Weight: {{convert|3280|lb|abbr=on}}
* Diameter: {{convert|21|in|abbr=on}}
* Range / Speed:
**Low speed: {{convert|9000|yard|m}} at {{convert|31|kn|kph}}
**High speed: {{convert|4500|yards|m}} at {{convert|46|kn|kph}}
* Guidance system: Gyroscope
* Warhead: {{convert|643|lb|abbr=on}} of [[Torpex]]
* Date deployed: 1931
* Date withdrawn from service: 1975–1980

== See also ==
'''Related development'''
*[[Mark 15 torpedo|Mark 15 Torpedo]]
*[[Mark 16 torpedo|Mark 16 Torpedo]]
*[[Mark 18 torpedo|Mark 18 Torpedo]]
'''Weapons of comparable role, configuration, and era'''
*[[Type 93 torpedo|Type 93 Torpedo]]
*[[G7e torpedo|G7e Torpedo]]
'''Related lists'''

* [[American 21 inch torpedo]]es
* [[British 21-inch torpedo|British 21 inch torpedoes]]

== References ==
=== Citations ===
{{reflist|colwidth=30em}}

=== Sources ===
* {{Citation |last=Blair |first=Clay Jr. |title=Silent Victory |location=Philadelphia |publisher=Lippincott |year=1975 |isbn=0-553-01050-6}}
* {{Citation |last=Newpower |first=Anthony |title=Iron Men and Tin Fish: The Race to Build a Better Torpedo during World War II |publisher=Praeger Security International |year=2006 |isbn=0-275-99032-X}}
* {{Citation |last=Roscoe |first=Theodore |title=Pig Boats: The True Story of the Fighting Submariners of World War II |location=New York |publisher=Bantam |year=1967 |oclc=22066288}}. Originally published in 1949 as ''United States Submarine Operations in World War II''; Bantam version is abridged
* {{citation |first1=Buford |last1=Rowland |first2=William B. |last2=Boyd |date=1953 |title=U.S. Navy Bureau of Ordnance in World War II |publisher=Bureau of Ordnance |url=https://babel.hathitrust.org/cgi/pt?id=uc1.$b671188;view=1up;seq=107}}
* [http://www.navweaps.com/Weapons/WTUS_WWII.htm United States of America Torpedoes of World War II]
* {{Citation |last1=Wildenberg |first1=Thomas |last2=Polmar |first2=Norman |title=Ship Killer |date=2010 |publisher=Naval Institute Press |isbn=978-1-59114-688-9}}

== Further reading ==
*{{cite patent |country-code=US |patent-number=5790405 |title=Method and apparatus for detecting circular torpedo runs |inventor-first=Robert J. |inventor-last=Buchler |assign1=Litton Systems, Inc. |fdate=1995-09-22 |issue-date=4 August 1998 |ref=none}}
* {{Citation |last=Gannon |first=Robert |title=Hellions of the Deep: The Development of American Torpedoes in World War II |publisher=Pennsylvania State University Press |year=1996 |isbn=027101508X |ref=none}}
* {{Citation |title=Mark XIV Torpedo Case Study |last=Matthews |first=David F. |publisher=Naval Postgraduate School |location=Monterey, CA |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a550699.pdf |archive-url=https://web.archive.org/web/20141010235350/http://www.dtic.mil/dtic/tr/fulltext/u2/a550699.pdf |url-status=live |archive-date=10 October 2014 |date=26 February 2011 |id=NPS-AM-11-008 |ref=none}} (DTIC A550699)
* {{Citation |title=Instructions for upkeep & operation of the mark VI mod. 1 exploder mechanism |publisher=Bureau of Ordnance |series=Ordnance Pamphlet |year=1938 |id=OP 632 |oclc=51958048 |ref=none}}
* {{Citation |title=Torpoedoes: Mark 14 and 23 Types |publisher=Bureau of Ordnance |series=Ordnance Pamphlet |url=http://www.maritime.org/doc/torpedo/ |date=24 March 1945 |id=OP 635 |ref=none}}

== External links ==
{{Commons}}
* [http://www.ww2pacific.com/torpedo.html Dud torpedoes of WWII]
* {{cite web |url=http://diodon349.com/Torpedoman/Torpedoes_USN/mark_14_3A_torpedo_Mk_6_exploder.htm |archive-url=https://web.archive.org/web/20041013135156/http://www.diodon349.com/Torpedoman/Torpedoes_USN/mark_14_3A_torpedo_Mk_6_exploder.htm |url-status=usurped |archive-date=13 October 2004 |title=Mark 14-3A Torpedo and its MK 6 Exploder |access-date=3 March 2012}}
* [http://www.reocities.com/pentagon/1592/ustorp2.htm "The Great Torpedo Scandal, 1941-43" October 1996 issue of Submarine Review] {{Webarchive|url=https://web.archive.org/web/20140201210109/http://www.reocities.com/pentagon/1592/ustorp2.htm |date=2014-02-01 }}
* https://issuu.com/reprospace/docs/num_q4_winter_2013
* [http://www.maritime.org/doc/tdc/index.htm Original Manual for the ''Torpedo Data Computer Mark 3'']
* {{cite book |author=Bureau of Ordnance |title=Tactical Data for Torpedoes Mark XIV & Mark XIV-1 High & Low Power |publisher=Navy Department |location=Washington D.C. |series=Ordnance Data Pamphlet |id=O.D. No. 3699 |date=4 December 1941 |url=https://maritime.org/doc/pdf/torp-mk14-tactical.pdf |ref=none}}

{{Mark-series torpedoes}}

{{DEFAULTSORT:Mark 14 Torpedo}}
[[Category:Torpedoes of the United States]]
[[Category:World War II naval weapons]]
[[Category:World War II weapons of the United States]]