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Q-ship

Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open fire and sink them.

They were used by the British Royal Navy and the German Kaiserliche Marine during the First World War and by the Royal Navy, the Kriegsmarine, the Imperial Japanese Navy, and the United States Navy during the Second World War (1939–45).

Though legally recognised as an acceptable tactic of military deception, they have attracted much controversy, enjoying only marginal success during WWI and none in WWII.

Etymology
Short for Queenstown in Ireland, as Haulbowline Dockyard in Cork Harbour was responsible for the conversion of many mercantile steamers to armed decoy ships in World War One, although the majority appear to have been converted in larger navy yards such as Devonport.

Early uses of the concept
The general idea and legal framework for the Q-ship derives from the classic ruse de guerre of "sailing under false colours". As a long standing element of naval tactics, warships may legally disguise themselves in various ways in transit, so long as the proper flags are hoisted before firing commences. Numerous examples exist of the tactic, used both defensively and offensively.

Examples of the tactic used against commerce raiders include HMS Kingfisher (1675) in the 1670s and French disguised brigs during the French Revolutionary Wars. An example of the latter was beaten back by the privateer lugger Vulture out of Jersey.

Royal Navy
In 1915, during the First Battle of the Atlantic, Britain was in desperate need of a countermeasure against the U-boats that were strangling its sea-lanes. Convoys, which had proved effective in earlier times (and would again prove effective during the Second World War), were rejected by the resource-strapped Admiralty and the independent captains. Depth charges of the time were relatively primitive, and almost the only chance of sinking a submarine was by gunfire or by ramming while on the surface. The problem was how to lure the U-boat to the surface.

A solution to this was the creation of the Q-ship, one of the most closely guarded secrets of the war. Their codename referred to the vessels' home port, Queenstown, in Ireland. These became known by the Germans as a U-Boot-Falle ("U-boat trap"). A Q-ship would appear to be an easy target, but in fact carried hidden armaments. A typical Q-ship might resemble a tramp steamer sailing alone in an area where a U-boat was reported to be operating.

Torpedoes were expensive, and a submarine only carried a limited number of them, ideally employed when the vessel is submerged and invisible to her target. Ammunition for a deck gun, oppositely, was inexpensive and plentiful in comparison. As a result, submarine captains preferred to surface and use their deck gun on easy or already weakened targets.

By seeming to be a suitable target for the U-boat's deck gun, a Q-ship was intended to lure a submarine into surfacing. Once the U-boat was vulnerable, perhaps even gulled further by pretence of some crew dressed as civilian mariners "abandoning ship" and taking to a boat, the Q-ship would drop its panels and immediately open fire with its deck guns. At the same time, the vessel would reveal her true colours by raising the White Ensign (Royal Navy flag). When successfully fooled, a U-boat could quickly become overwhelmed by several guns to its one, or defer from firing and try to submerge before it became mortally wounded.

The first Q-ship victory was on 23 June 1915, when the submarine HMS C24, cooperating with the decoy vessel Taranaki, sank SMU U-40 (Germany) off Eyemouth. The first victory by an unassisted Q-ship came on 24 July 1915 when Prince Charles sank SMU U-36. The civilian crew of Prince Charles received a cash award. The following month an even smaller converted fishing trawler renamed HM ARMED SMACK Inverlyon successfully destroyed SMU UB-4 near Great Yarmouth. Inverlyon was an unpowered sailing ship fitted with a small 3-pounder (47 mm) gun. The British crew fired nine rounds from their 3-pounder into UB-4 at close range, sinking her with the loss of all hands despite the attempt of Inverlyon's commander to rescue one surviving German submariner.

On 19 August 1915, HMS Baralong sank SMU U-27 (Germany), which was preparing to attack the nearby merchant ship Nicosian. About a dozen of the U-boat sailors survived and swam towards the merchant ship. The commanding officer, allegedly fearing that they might scuttle her, ordered the survivors to be shot in the water and sent a boarding party to kill all who had made it aboard. This became known as the "Baralong incident".

HMS Farnborough (Q.5) sank SMU U-68 on 22 March 1916. Her commander, Gordon Campbell, was awarded the Victoria Cross (VC). New Zealanders Lieutenant Andrew Dougall Blair and Sub-Lieutenant William Edward Sanders faced three U-boats simultaneously in Helgoland (Q.17) while becalmed and without engines or wireless. Forced to return fire early, they managed to sink one U-boat and avoid two torpedo attacks. Sanders was promoted to lieutenant commander, eventually commanding the topsail schooner HMS Prize in command of which he was awarded the Victoria Cross for an action on 30 April 1917 with SMU U-93, which was severely damaged. Helgoland, while the ship sustained heavy shellfire, waited until the submarine was within 80 yd, whereupon he hoisted the White Ensign and Prize opened fire. The submarine appeared to sink and he claimed a victory. However, the badly damaged submarine managed to struggle back to port. With his ship accurately described by the survivors of U-93, Sanders and his crewmen were all killed in action when they attempted a surprise attack on SMU UB-48 on 14 August 1917.

According to Warships of World War I by H. M. LeFleming, the Royal Navy converted 58 from merchant ships (18 were sunk by U-boats), in addition to 40 Flower-class sloop and 20 PC-boats. However Conway's All the World's Fighting Ships 1906–1921 quotes no fewer than 157 named submarine decoy vessels converted from other types of ship, in addition to another ten whose name was unknown. It agrees with LeFleming about the number of sloops and PC-boats. These ones were completed as Q-ships, disguised as coastal freighters and differed from regular service PC-boats. None were lost in the war. The Flower-class sloops were designed on merchant ship lines thus making them easily adaptable for conversion to Q-ships, 39 being completed as such while the other was converted after being torpedoed. These all had single funnels as the merchant ship silhouette was left to the builders. The "Flower-Q's" were employed mainly on convoy and anti-submarine work. Nine were lost during the war.

After the war, it was concluded that Q-ships were greatly overrated, diverting skilled seamen from other duties without sinking enough U-boats to justify the strategy. Estimates differ due to the uncertainty of the attribution of lost submarines, but in a total of approximately 150 engagements, British Q-ships destroyed or assisted in the loss of around 12-15 U-boats and damaged 60, at a cost of 27-38 Q-ships lost out of ~200. Q-ships were thus responsible for under 10% of all U-boats sunk, ranking them well below the use of ordinary minefields in effectiveness. Around half of Q-ship successes took place in June to September 1915, after which the ships were much less effective. With the second round of unrestricted submarine warfare in 1917, Q-ships sunk only 3 submarines, dwarfed by the ~28 sunk by undisguised warships.

Imperial German Navy
The Imperial German Navy commissioned six Q-boats during the Great War for the Baltic Sea into the Handelsschutzflottille. None were successful in destroying enemy submarines. The German Q-ship Schiff K heavily damaged the Russian submarine Gepard of the Bars-class submarine on 27 May 1916. The famous Möwe and Wolf were merchant raiders, vessels designed to disrupt enemy trade and sink merchantmen, rather than attack enemy warships.

Germany
Germany employed at least 13 Q-ships, including the Schürbeck which sank the British submarine HMS Tarpon (N17). The German GERMAN AUXILIARY CRUISER Atlantis, which sank a number of ships with a total tonnage of 145,960 t including the Norwegian tanker Tirranna on 10 June 1940, was more of a merchant raider.

Japan
The Imperial Japanese Navy converted the 2,205-ton merchant ship, Delhi Maru, into a Q-ship. On 15 January 1944, she departed from Nagaura (now Sodegaura on Tokyo Bay) on her first mission in company with the submarine chaser Ch-50 and the netlayer Tatu Maru. At 22:00 that evening, the vessels were detected by the submarine USS Swordfish (SS-193), which launched three torpedoes. Delhi Maru was hit by all three on her port bow; following a number of internal explosions, she broke in two, the forward section sinking immediately and the aft section sinking later in heavy seas. Although  Swordfish was depth charged by Ch-50, she escaped unscathed.

United Kingdom
Nine Q-ships were commissioned by the Royal Navy in September and October 1939 for work in the North Atlantic:

 * 610-ton HMS Chatsgrove (X85) ex-Royal Navy P-class sloop PC-74 built 1918
 * 5,072-ton HMS Maunder (X28) ex-King Gruffyd built 1919
 * 4,443-ton HMS Prunella (X02) ex-Cape Howe built 1930
 * 5,119-ton HMS Lambridge (X15) ex-Botlea built 1917
 * 4,702-ton HMS Edgehill (X39) ex-Willamette Valley built 1928
 * 5,945-ton HMS Brutus (X96) ex-City of Durban built 1921
 * 4,398-ton HMS Cyprus (X44) ex-Cape Sable built 1936
 * 1,030-ton HMS Looe (X63) ex-Beauty built 1924
 * 1,090-ton HMS Antoine (X72) ex-Orchy built 1930

Prunella and Edgehill were torpedoed and sunk on 21 and 29 June 1940 without even sighting a U-boat. The rest of the vessels were paid off in March 1941 without successfully accomplishing any mission.

The last Royal Navy Q-ship, 2,456-ton HMS Fidelity (D57), was converted in September, 1940, to carry a torpedo defense net, four 4 in guns, four torpedo tubes, two OS2U Kingfisher floatplanes, and Motor Torpedo Boat 105. Fidelity sailed with a French crew, and was sunk by GS U-435 on 30 December 1942 during the battle for Convoy ON-154.

United States
By 12 January 1942, the British Admiralty's intelligence community had noted a "heavy concentration" of U-boats off the "North American seaboard from New York to Cape Race" and passed along this fact to the United States Navy. That day, GS U-123 (1940) under Kapitänleutnant Reinhard Hardegen, torpedoed and sank the British steamship Cyclops, inaugurating Paukenschlag (literally, "a strike on the kettledrum" and sometimes referred to in English as "Operation Drumbeat"). U-boat commanders found peacetime conditions prevailing along the coast: towns and cities were not blacked-out and navigational buoys remained lit; shipping followed normal routines and "carried the normal lights." Paukenschlag had caught the United States unprepared.

Losses mounted rapidly. On January 20, 1942, Commander-in-Chief, United States Fleet (Cominch) Earnest J. King, sent a coded dispatch to Commander, Eastern Sea Frontier (CESF), requesting immediate consideration of the manning and fitting-out of "Queen" ships to be operated as an antisubmarine measure. The result was "Project LQ."

Five vessels were acquired and converted secretly at the Portsmouth Naval Shipyard, Kittery, Maine:

 * the Boston beam trawler MS Wave, which briefly became the auxiliary minesweeper USS Eagle (AM-132) before becoming USS Captor (PYc-40),
 * SS Evelyn and Carolyn, identical cargo vessels that became USS Asterion (AK-100) and USS Atik (AK-101) respectively (these hull numbers were actually duplicates of the USS Lynx and the USS Lyra respectively),
 * the tanker SS Gulf Dawn, which became USS Big Horn (AO-45), and
 * the schooner Irene Myrtle, which became USS Irene Forsyte (IX-93).

The careers of all five ships were almost entirely unsuccessful and very short, with USS Atik sunk on its first patrol with all hands on 26 March 1942. COMINCH strongly criticized the program and all Q-ships patrols ended in 1943.

American Q-ships also operated in the Pacific Ocean. One was USS Anacapa (AG-49) formerly the lumber transport Coos Bay which was converted to Q-ship duty as project "Love William". Anacapa was not successful in engaging any enemy submarines, although she is believed to have damaged two friendly subs with depth charges when they were improperly operating in her vicinity. Anacapa was also withdrawn from Q-ship duty in 1943 and served out the remainder of World War II as an armed transport in the South Pacific and Aleutian Islands.

The US Navy did not use a consistent hull classification symbol for its Q-ships (AG, AK, AO, IX and PYc were all used). This and the unprecedented use of duplicate hull numbers for Asterion and Atik reflect the great secrecy attached to these ships.

Proposed use against modern pirates
Attacks on merchant ships by pirates originating on the Somalia coast have brought suggestions from some security experts that Q-ships be used again to tempt pirates into attacking a well-defended ship.

Survivors
A surviving example of the Q-ships is HMS Saxifrage, a Flower-class sloop of the Anchusa group completed in 1918. She was renamed HMS President (1918) in 1922 and served as the London Division RNR drill ship until 1988, when she was sold privately and remains moored at King's Reach on the Thames.

Q-ships in fiction
The Alfred Noyes poem "Kilmeny" is about a Q-ship, a British trawler equipped with two deck guns, that destroys a German submarine during World War I.

In Ernest Hemingway's novel Islands in the Stream, the main character Thomas Hudson commands a Q-ship for the US Navy around Cuba as he hunts the survivors of a sunken German U-boat.

In Edward L. Beach Jr.'s novel Run Silent, Run Deep, Japanese Q-ships make two appearances with one surprising the Walrus and the second being attacked by the Eel in the final battle of the story.

Malcolm Lowry's novel Under the Volcano (1947) tells the story of Geoffrey Firmin, an alcoholic British consul in the small Mexican town of Quauhnahuac, on the Day of the Dead, 2 November 1938. Geoffrey Firmin reflects back to his time as a naval officer during World War I, when he was court-martialed and subsequently decorated for his actions aboard a Q-ship (the captured German officers disappeared and were allegedly burned alive in the boiler).

In the Clive Cussler book series Oregon Files, the main base of operations is a Q-ship, a converted lumber carrier. The crew are mercenaries and former US covert and military personnel who carry out missions around the world in support of US policy while earning their living performing mercenary operations.

The 1951 movie Operation Pacific features a battle with a Q-Ship by the fictional submarine USS Thunderfish, inspired by an encounter with an enemy ship by the USS Growler.

In science fiction
As with other naval concepts, the idea of a Q-ship has also been applied to space vessels in fictional works:

Q-ships feature prominently in David Weber's Honor Harrington series of books. Harrington destroys a Q-ship in the first novel, On Basilisk Station, and commands a squadron of Q-ships in the sixth novel, Honor Among Enemies. In the tenth book in the series, War of Honor, Thomas Bachfisch commands a pair of privately owned Q-ships.

In the Jan/Feb 2020 issue of Analog Science Fiction and Fact, Joel Richards has a short story titled "Q-ship Militant".

In DC Comics Star Spangled War Stories #71 (reprinted in DC Comics Weird War #1) the story "The End of the Sea Wolf!" is a postwar "flashback" story of a U-boat commander engaging a Q-ship in WWII.

title: Q-ship


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Talk:Q-ship

Missing Criticism
When you read the article you can get the idea that Q-Ships were a perfectly legal, brilliant idea to counter the treat of german submarines. The british were certainly in desperation yet the usage of concealed warships was considered a warcrime by the maritime war of these days, which explains why it was "one of the most closely guarded secrets of the war." German submarines operated under the prize rules which demanded that every merchant vessel had to be stopped, it's cargo checked and only if it was transporting contraband it was allowed to be sunk, after the crew was on lifeboats in safe distance, usually combined with an SOS. Only then the ship was sunk by using the deck cannon to save precious torpedoes. It was the utopia of a civilized warfare without unnecessary casualities. The result of the Q-ship usage was that the war on sea got noteworthy brutalized on both sides, leading to the unconditional submarine warfare with submarines ignoring the prize rule by just firing without warning, out of paranoia to not make themselves a victim to Q-ships. The invention of Q-ships can be seen as a premise which might have been a main reason for the Lusitania incident that would follow in May 1915. Another example worth mentioning in this article were the Baralong incidents. The HMS Baralong sunk 2 submarines by sailing under US flag and thus appearing as a neutral ship. After U-27 was sunk every surviving german sailor, still swimming in the sea or on board of the Nicosian was shot by the crew of the Baralong under order of it's commanding officer Lieutenant Godfrey Herbert. — Preceding unsigned comment added by 188.108.151.179 (talk) 13:28, 26 September 2015 (UTC)
 * I agree with this edit. Therefor I deleted one phrase in the lemma. --Orik (talk) 13:29, 12 March 2016 (UTC)

 * I am concerned by this criticism. If it is true, then the article definitely ought to be edited to say so.

IceDragon64 (talk) 20:10, 25 March 2018 (UTC)

 * I was about to write a similar criticism--if this was a war crime (and someone know which maritime treaty it violated) this is a *huge* oversight, one which arguably gives a different cast to the entire war (at least in terms of the U.S.'s entry into it). Historian932 (talk) 19:54, 3 April 2018 (UTC)

 * It's quite evidently british propaganda. It's all over Wikipedia, really. The english are often portrayed as the bad guys on non-english entries, but even there the truth is "being improved" in creative ways. The Q ships were a ruse of war designed to trick the germans into killing innocent civilians to sway public opinion against them; nothing more.

190.46.205.93 (talk) 22:44, 3 January 2020 (UTC)

If it was "illegal" (as against immoral etc.), you should state what article of international law it infringed. The German U-boats certainly didn't chivalrously save all the crew of merchant ships before sinking them, from early in the war. For instance, on 10 April 1915 the British steamer Harpalyce was torpedoed without warning by SM UB-4 with loss of life. The submarine fired torpedoes at 3 other ships at the same time, all without warning, and claimed all sunk, but only Harpalyce was lost. SM UB-4 was later sunk by a Q-ship. Criticism of the use of Q-ships could well be justified, naturally. But we need the proper references. As for the statement that its "illegality" explains why it was "one of the most closely guarded secrets of the war", that's clearly nonsense. It was a closely guarded secret for the obvious reason that the British didn't want the Germans to know about the decoy ships because they would have lost something of their effectiveness. I believe they did in fact become known to the Germans quite soon, from reports of surviving U-boats attacked by them, but that's another matter METRANGOLO1 (talk) 18:21, 17 October 2020 (UTC)

O, those chivalrous Germans! — Preceding unsigned comment added by 82.15.39.58 (talk) 07:36, 18 October 2020 (UTC)

 * Nice theory but it just isn't true. The U-boats were instructed to sink ships without warning *before* Q-ships. Q-ships was a response to unrestricted submarine warfare, not the other way round. The first Baralong incident was probably a war crime but ruse de guerre isn't generally, and also statistically crew from U-boats sunk by Q-ships actually had a better chance of surviving than those sunk by other methods. Fangz (talk) 11:59, 18 April 2024 (UTC)
 * Besides the Germans did the same thing. If you disguise your commerce raiders as neutral civilian craft, you can hardly complain about ships that did the same thing but targeting military vessels, as opposed to civilian ones. 82.2.239.38 (talk) 15:53, 18 April 2024 (UTC)

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WAS Gold Star a Q-ship?
Although it was an armed merchant ship, that alone does not make it a Q ship, yet it is described as such both here and on its own Page. I am tempted to remove the paragraph all together. Can anyone find evidence that it was armed secretly, in order to attract surface attack by submarine?

IceDragon64 (talk) 19:50, 25 March 2018 (UTC)

 * I support removing Gold Star from this page. She was more like a spy ship rather than Q-ship. MKFI (talk) 18:08, 22 May 2019 (UTC)

 * Agree entirely. I've changed the description in the ship's page and will move the section to Spy ship article.Cosmicdense (talk) 00:15, 2 October 2020 (UTC)

Naming
After Queenstown? I thought it was a bad pun on 'ship of the line' --- a queue-ship, geddit? 157.131.93.97 (talk) 19:58, 4 December 2019 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Q-ship


text:
PT boat

A PT boat (short for patrol torpedo boat) was a motor torpedo boat used by the United States Navy in World War II. It was small, fast, and inexpensive to build, valued for its maneuverability and speed but hampered at the beginning of the war by ineffective torpedoes, limited armament, and comparatively fragile construction that limited some of the variants to coastal waters. In the US Navy they were organized in Motor Torpedo Boat Squadrons (MTBRONs).

The PT boat was very different from the first generation of torpedo boat, which had been developed at the end of the 19th century and featured a displacement hull form. These first generation torpedo boats rode low in the water, displaced up to 300 tons, and had a top speed of 25 to 27 kn. During World War I Italy, the US, and UK developed the first high-performance, gasoline-powered motor torpedo boats (often with top speeds over 40 knots) and corresponding torpedo tactics, but these projects were all quickly disbanded after the Armistice. Design of World War II PT boats continued to exploit some of the advances in planing hull design borrowed from offshore powerboat racing and used multiple lightweight but more powerful marinized aircraft-derived V-12 engines, and thus were able to advance in both size and speed.

During World War II, PT boats engaged enemy warships, transports, tankers, barges, and sampans. Some were converted into gunboats which could be effective against enemy small craft, especially armored barges used by the Japanese for inter-island transport. Several saw service with the Philippine Navy, where they were named "Q-boats". Primary anti-ship armament on the standard PT boat was four 21-inch Mark 8 torpedoes, each had a 466 lb TNT warhead and had a range of 16000 yd at 36 kn. Two twin .50-inch (12.7 mm) M2 Browning heavy machine guns were mounted for anti-aircraft defense and general fire support. Some boats carried a 20 mm Oerlikon cannon. Propulsion was via a trio of Packard 4M-2500 and later 5M-2500 supercharged gasoline-fueled, liquid-cooled V-12 marine engines.

Nicknamed "the mosquito fleet" and "devil boats" by the Japanese, the PT boat squadrons were hailed for their daring and earned a durable place in the public imagination that remains strong into the 21st century. Their role was replaced in the U.S. Navy by fast attack craft.

Development
At the outbreak of war in August 1914, W. Albert Hickman devised the first procedures and tactics for employing fast maneuverable seaworthy torpedo motorboats against capital ships, and he presented his proposal to Rear Admiral David W. Taylor, the chief of the US Navy's Bureau of Construction and Repair. In September 1914, Hickman completed plans for a 50 ft "Sea Sled" torpedo boat and submitted these to the Navy in hopes of obtaining a contract. While favorably received, Secretary of the Navy Josephus Daniels rejected the proposal since the US was not at war, but Hickman was advised to submit his plans and proposal to the British Admiralty, which was done the following month. The Admiralty found it interesting but thought that "no fast boat of 50' to 60' length would be sufficiently seaworthy", so Hickman built and launched his own privately financed 41 ft sea sled capable of carrying a single 18-inch Whitehead Mark 5 torpedo. In February 1915, this Hickman sea sled demonstrated 35 kn speeds in rough winter seas off Boston to both US and foreign representatives, but again he received no contracts. The Admiralty representative for this sea sled demonstration was Lieutenant G.C.E. Hampden. In the summer of 1915, Lieutenants Hampden, Bremner, and Anson approached John I. Thornycroft & Company about developing a small high speed torpedo boat, and this effort eventually led to the Coastal Motor Boat which first went into service in April 1916.

Meanwhile, in August 1915, the General Board of the United States Navy approved the purchase of a single experimental small torpedo boat that could be transportable. This contract for C-250 ended up going to Greenport Basin and Construction Company. When it was delivered and tested in the summer of 1917, it was not deemed a success, so a second boat (C-378) of the sea sled design was ordered from Hickman in either late 1917 or early 1918 (conflicting dates). Using his previous design from September 1914 and the previous unsuccessful bid for C-250, the C-378 was completed and fully tested just in time to be cancelled as a result of the Armistice. With a full loaded weight of 56,000 lb, C-378 made a top speed of 37 kn with 1400 hp, and maintained an average speed of 34.5 kn in a winter northeaster storm with 12 to 14 ft seas, which would still be considered exceptional even 100 years later.

The sea sled did not surface again as a torpedo boat topic until 1939 but continued to be used by both the Army and Navy as rescue boats and seaplane tenders during the 1920s and 1930s. In 1922, the US Navy reconsidered using small internal combustion engine powered torpedo boats. As a result, two types—45 ft and 55 ft—of British Royal Navy Coastal Motor Boats were obtained for testing. The larger boat was used for experiments until 1930. In 1938, the US Navy renewed their investigation into the concept by requesting competitive bids for several different types of motor torpedo boats but excluded Hickman's sea sled. This competition led to eight prototype boats built to compete in two different classes. The first class was for 54 ft boats, and the second class was for 70 ft boats. The resulting PT boat designs were the product of a small cadre of respected naval architects and the Navy.

Design competition
On 11 July 1938 the Navy issued multiple 'notice of competitions' for proposals of design of four separate types of boat: a 165-foot subchaser, a 110-foot subchaser, a 70-foot motor torpedo boat, and a 54-foot motor torpedo boat. The winning design proposals would each receive a prize of $15,000 with $1,500 for designs that reached the final part of the competition each to be given out on 30 March 1939.

The larger boat proposal was not to exceed 80 feet and was to carry at least two 21-inch torpedoes, four depth charges, and two .50-cal machine guns. The performance specification was to achieve 40 knots with an operating radius of 275 miles at top speed (550 miles at cruising speed). The smaller boat proposal was to weigh no more than 20 tons so that it could be easily transported by larger cargo ships. Its maximum top speed was also to be 40 knots, but specified operating radius was to be 120 miles at top speed and 240 miles at cruising speed. Equipped armament for the smaller proposal was to be either two torpedoes and two depth charges, or .50-cal machine guns and a smokescreen generator.

By September 1938 the U.S. Navy had received 24 design proposals for the small boat and 13 design proposals for the larger 70-footer. Of those proposals submitted, three 54-ft designs and five 70-ft designs were of interest, and the designers were asked to submit more detailed plans for both the 54 and 70 foot boats by no later than 7 November. On 21 March 1939 Sparkman & Stephens won the prize in the 70-foot class, and George Crouch (for Henry B. Nevins, Inc.) had won the design proposal for the 54-foot class. After winning the design competition for the smaller PT boat, Crouch wrote that Hickman's sea sled design would be far superior "in either rough or smooth water to that of the best possible V-bottom or hard chine design". Earlier when sea sleds were specifically excluded, Crouch had informed the Bureau of Ships that the sea sled was the best type of vessel for the job.

Following the competition, contracts were placed for construction of boats: 25 May 1939 to Higgins Industries for two boats (PT5 and PT6) of the Sparkman & Stephens design, scaled up to an overall length of 81 feet; 8 June 1939 to Fogal Boat Yard (PT-1 and PT-2) and Fisher Boat Works (PT-3 and PT-4) for the Crouch design; to the Philadelphia Navy Yard (PT-7, PT-8) for 81-foot boats designed by the Bureau of Ships. These last two boats were constructed mainly out of aluminum and had 4 engines. Higgins built an additional PT-6 "Prime" redesigned by Andrew Higgins personally using his own methods. Later that same year, Higgins built PT-70 (at their own expense) that incorporated slight improvements over PT-6 Prime.

Later, rigorous testing performed on each design as well as changes in armament revealed limitations or problems that had to be fixed before they could meet required performance specifications. As a result, the Navy ordered further investigation and refinement of the existing designs until a satisfactory working design could be obtained. At the same time, Henry R. Sutphen of Electric Launch Company (Elco) and his designers (Irwin Chase, Bill Fleming, and Glenville Tremaine) visited the United Kingdom in February 1939 at the Navy's request to see British motor torpedo boat designs with a view to obtaining one that could be used as a check on the Navy's efforts. While visiting the British Power Boat Company, they purchased a 70 ft private venture motor torpedo boat (MTB) design—PV70, later renamed PT-9—designed by the power boat racer Hubert Scott-Paine. PT-9 was to serve as the prototype for all the early Elco PT boats. After the initial competition, in late 1939 the Navy contracted Elco to build 11 copies of PT-9.

On 11 October 1940 an agreement between the Navy and Huckins Yacht Corporation was finalized. The Navy would provide engines and Huckins would build a PT boat at their own expense, with the caveat that the boat (upon completion) would be offered to the Navy for a later sum. This 72 ft boat (designated MT-72) later became PT-69. Huckins reported a profit of $28.60 on this transaction.

Background
In March 1941, during a heavy weather run from Key West to New York by Motor Torpedo Boat Squadron 2 (MTBRON 2), Elco 70-footers pounded heavily in 8 to 10 ft waves even at moderate speeds, and seas continuously broke high over the bows. Operating personnel reported extreme discomfort and fatigue. All boats suffered from some sort of structural failure: forward chine guards ripped away, bottom framing under bows broken, side planking cracked [indicating lack of longitudinal strength], and other weaknesses were reported. In April MTBRON 1 reported enthusiasm over the 81-foot Higgins (PT-6), and with the PT-6 showing such good seakeeping, further purchase of Scott-Paine boats was unnecessary. In early 1941 the U.S. Navy Bureau of Ships lent Packard engines to both Huckins and Higgins, which wanted to build competitive boats at their own expense.

A Chief of Naval Operations PT Boat Conference convened in May 1941 to discuss future PT characteristics. All PTs prior to the 77 ft Elcos had been found defective, and it was probable the extended 70 ft Elco would not be an improvement. The conference recommended a series of comparative tests to evaluate what turned out to be five new designs of motor torpedo boats. The conference strongly recommended that no more Elco 77-footers be ordered until the tests had shown that they were indeed satisfactory.

Board of Inspection and Survey
The Board of Inspection and Survey, headed by Rear Admiral John W. Wilcox, Jr., conducted comparative service tests off New London, Connecticut, from 21 to 24 July 1941, using the following boats:

 * PT-6: 81 ft Higgins; 3 Packard 1200 hp engines.
 * PT-8: 81 ft Philadelphia Navy Yard; aluminum hull; 2 Allison 2000 hp engines, 1 Hall-Scott 550 hp engine.
 * PT-20: 77 ft Elco; 3 Packard 1200 hp engines; equipped with special propellers; special strengthening added to hull framing and deck.
 * PT-26, -30, -31, -33: Same as PT-20, except with standard propellers and without special strengthening.
 * PT-69: 72 ft Huckins; 4 Packard 1200 hp engines.
 * PT-70: 76 ft Higgins; 3 Packard 1200 hp engines.
 * One 70 ft MRB-8 (Motor Rescue Boat), built for the Royal Navy by Higgins; 3 Hall-Scott 900 hp engines.

Each member of the board conducted an independent inspection of every boat class, evaluating them for structural sufficiency, habitability, access, arrangement for attack control, and communication facilities. Boats were also evaluated under two conditions of armament loading: loaded and fully equipped with four 21 in torpedoes and sufficient fuel to operate 500 NM at 20 knots; and fully loaded with two 21 in torpedoes and ten 300 lb depth charges with sufficient fuel to operate 500 nmi at 20 kn. Boats would have their tactical parameters of each design determined by photographs from an airship.

First open-ocean trial
Lastly, there was a demonstration of seakeeping qualities and hull strength by making a run at maximum sustained speed in the open ocean. An accelerometer was installed in the pilot house of each boat to record "pounding". Conducted on 24 July 1941, this open-water trial, 190 nmi at full throttle, was referred to by PT personnel as the "Plywood Derby". The course started from the mouth of New London Harbor, to Sarah Ledge, then led around the eastern end of Block Island, then around Fire Island Lightship, finishing at Montauk Point Whistling Buoy.

At the time, only the Elco 77-footers were loaded with armament. The other competitors had copper ingots added topside (mostly in the turrets) to make up the difference. This resulted in severe conditions for several of the boats during the trial and accounted for the transverse failure in PT-70's deck and subsequent hull failure as the copper fell into the hull. Nine boats participated in the trial. Six boats completed the trial, while three withdrew: PT-33 suffered structural damage off Block Island; PT-70 was damaged by loose copper ingots; and MRB developed engine trouble at the start of the run.

By class, PT-20, an Elco 77-footer, came in first with an average speed of 39.72 kn; followed by PT-31, with an average speed of 37.01 kn; PT-69, the Huckins 72 ft boat, was third with an average speed of 33.83 kn; PT-6, the Higgins 81-footer, with an average speed of 31.4 kn was fifth; and PT-8, the Philadelphia Navy Yard boat, was last, at 30.75 kn. The other two Elco boats, PT-30 and PT 23 (standby boat), followed PT-31, placing before PT-69.

The accelerometers ranked the boats as follows: first was the Philadelphia Navy Yard PT-8 with the least pounding, second was the Huckins PT-69, third was the Higgins PT-6, and last were the Elco 77-footers.

Second open-ocean trial
Because of the problem with ingot loading, a 185 nmi trial with the PTs fully fitted out was conducted on 12 August 1941. Four boats—PT-8, PT-69, PT-70, and MRB—returned and Elco sent two new boats, PT-21 and PT-29. During this trial, boats faced heavier seas, as high as 16 ft. All except the Huckins (PT-69) completed the run. The Huckins withdrew because of a bilge stringer failure. The Higgins 76-footer (PT-70) completed the entire run but also suffered structural failures: attachments between planking and web frames pulled loose and deck fastenings near engine hatches showed extensive failures. PT-21 suffered minor cracks in the deck in the same location, but not to the same extent, as previously observed in PT-26, PT-30, and PT-33. PT-29 was assigned as a pace boat with PT-8 in order to generate a pounding comparison.

The average speed results from the 185 nmi course were: Elco 77-footer (PT-21), 27.5 kn; Higgins 76-footer (PT-70), 27.2 kn; Higgins MRB and Philadelphia Navy Yard boat (PT-8), 24.8 kn. Accelerometers were again installed in the pilot house of each boat, but the readings were incomplete because the violent motion of the boats made observations difficult and in some cases necessitated abandonment of the observing stations. Further, many of those taken were beyond the normal range of the instruments and were considered inaccurate. Elco boats were found to pound heavily and confirmed previous reports of crew discomfort.

Findings
The Elco 77-Footer Design Demonstrates:
 * 1) Ability to make a maximum sustained speed of 39.7 knots; maximum speed 44.1 knots with heavy ordnance load.
 * 2) Maneuverability satisfactory except for a large turning circle of 432 yd.
 * 3) Space available for four 21" torpedo tubes.
 * 4) Structural weaknesses resulting in transverse fractures of deck planking.
 * 5) Tendency to pound heavily in a seaway.
 * 6) Fittings and finish unnecessarily refined.
 * 7) Cost to the Government fully equipped $302,100.

The Huckins 72-Foot Design Demonstrates:
 * 1) Ability to make a maximum sustained speed of 33.8 knots; maximum speed 43.8 knots with light ordnance load.
 * 2) Maneuverability satisfactory with a turning circle of 336 yd.
 * 3) Space available for two 21" torpedo tubes and ten 300 lb depth charges.
 * 4) Structural weaknesses resulting in fracture of bilge stringers.
 * 5) Very little tendency to pound in a seaway.
 * 6) Fittings and finish appropriate for a motor torpedo boat.
 * 7) Cost to the Government fully equipped $263,500.

The Navy Yard Philadelphia 81-Foot Design Demonstrates:
 * 1) Ability to make a maximum sustained speed of 30.7 knots; maximum speed 33.9 knots with light ordnance load.
 * 2) Maneuverability unsatisfactory due to inability to reverse outboard engines with a large turning circle of 443 yd
 * 3) Space available for two 21" torpedo tubes and ten 300 lb depth charges.
 * 4) Structural strength is adequate.
 * 5) Tendency to pound severely in a seaway.
 * 6) Fittings (Navy standard for combatant ships) entirely too heavy and cumbersome for this type of craft. Finish adequate.
 * 7) Cost to the Government fully equipped $756,400.

The Higgins 81-Foot Design Demonstrates:
 * 1) Ability to make a maximum sustained speed of 31.4 knots; maximum speed 34.3 knots with heavy ordnance load.
 * 2) Maneuverability satisfactory with a turning circle of 368 yards.
 * 3) Space available for four 21" torpedo tubes.
 * 4) Structural strength adequate.
 * 5) Moderate tendency to pound in a seaway.
 * 6) Fittings and finish satisfactory.
 * 7) Cost to the Government fully equipped $206,600.

The Higgins 76-Foot Design Demonstrates:
 * 1) Maximum sustained speed of 27.2 knots in rough seas; maximum speed 40.9 knots.
 * 2) Maneuverability satisfactory, turning circle not determined photographically, estimated 300 yards.
 * 3) Space available for four 21" torpedo tubes.
 * 4) Structural weaknesses caused failures in transverse bottom framing, separation of side planking from framing and extensive failures of deck fastenings.
 * 5) Moderate tendency to pound in a seaway.
 * 6) Fittings and finish satisfactory.
 * 7) Cost to the Government fully equipped $265,500.

The board arrived at the following recommendations:
 * 1) That the Packard power plant having been found highly satisfactory be adopted as standard for future construction.
 * 2) That the ordnance installation of future motor torpedo boats consist of two torpedo tubes, machine guns and depth charges.
 * 3) That the Huckins 78-foot (PT-69) design be considered acceptable for immediate construction.
 * 4) That the Higgins 80-foot (PT-6) design suitably reduced in size to carry such ordnance loads as are required by our Navy be considered acceptable for immediate construction.
 * 5) That the Elco 77-foot design be considered acceptable for future construction provided changes in the lines are made to reduce the tendency to pound in a seaway, and the structure be strengthened in a manner acceptable to the Bureau of Ships.
 * 6) That the Philadelphia 81-foot boat (PT-8') be stripped of excess weight and be re-engined with three Packard engines.

The board also had the following opinion on structural sufficiency: "During the first series of tests (21–24 July) the Huckins design (PT-69), the Philadelphia design (PT-8) and the Higgins design (PT-6) completed the open sea endurance run without structural damage. The Higgins 70' (British) boat did not complete this run because of engine trouble. The Higgins 76' (PT-70) and boats of the Elco 77' (PT-20 Class) developed structural failures even under moderate weather conditions prevailing. In the interval between the first and second test periods the PT-70 was repaired and an effort made to eliminate the causes of the structural failures. However, during the second endurance run, which was made in a very rough sea for this size boat, structural failures again occurred in PT-70. PT-69 and PT-21 experienced structural failures during the second run though these were much more localized as compared with those found on PT-70. The Board is of the opinion that certain changes in design are required to enable PT-69 and boats of the PT-20 Class to carry safely their military loads in rough weather."

The board results provided very important benchmarks in the infancy of PT boat development. This type of craft presented design challenges that were still issues decades after, but there are some significant conclusions from the above recommendations and their order of merit. Those are:

 * 1) The Packard were the engines of choice.
 * 2) The Huckins 72-foot (PT-69) and a reduced Higgins 81-foot (PT-6) design were to be placed into production. Following an October 1941 BuShips conference and its new set of navy design requirements which included room to support four 21 in torpedoes and an upper length restriction of 82', the next two orders for pre-war PT boats (PT-71 through PT-102) were awarded to Higgins and Huckins.
 * 3) Even though the Elco 77-footers posted the fastest speeds, all seven Elcos suffered from structural damage and severe pounding causing the Board to recommend a redesign to correct these deficiencies. Elco competed for the PT-71 to PT-102 contract but did not win due to their higher unit price. After the start of the war and significantly revising their unit cost, Elco received the next PT boat order after Higgins and Huckins. This was to be their new Elco 80-foot design.

Elco
The newly designed 80 ft Elco Naval Division boats were the longest of the three types of PT boats built for the Navy used during World War II. By war's end, more of the Elco boats were built (326 in all) than any other type of motor torpedo boat. While comparable in size to many wooden sailing ships in history, these 20 ft beam wooden-hulled craft were classified as boats in comparison with much larger steel-hulled destroyers, destroyer escorts, and corvettes. Five Elco boats were manufactured in knock-down kit form and sent to Long Beach Boatworks for assembly on the West Coast as part of an experiment and as a proof of concept.

Higgins
Higgins Industries produced 199 78 ft boats of the PT-71/PT-235, PT-265 and PT-625 classes. The Higgins boats had the same beam, full load displacement, engines, generators, shaft horsepower, trial speed, armament, and crew accommodation as the 80 ft Elco boats. Many Higgins boats were sent to the Soviet Union and Great Britain at the beginning of the war, so many of the lower-numbered squadrons in the U.S. Navy were made up exclusively of Elcos. U.S. Navy PT boats were organized into MTBRONs. The first Higgins boats for the U.S. Navy were used in the battle for the Aleutian Islands (Attu and Kiska) as part of Squadrons 13 and 16, and others (MTBRON15 and MTBRON22) in the Mediterranean against the Germans. They were also used during the D-Day landings on 6 June 1944.

Even though only half as many Higgins boats were produced, far more survive (seven hulls, three of which have been restored to their World War II configuration) than the more numerous Elco boats. Of the Elco boats, only three hulls (one restored) were known to exist as of 2016.

Huckins Yacht Corporation

Huckins and his innovative Quadraconic planing hull design were latecomers to PT boat design. Not invited to participate in the original design competition, by late 1940, Huckins had a meeting with Captain James M. Irish, Chief of Design, and offered to build a "planing seagoing hull" PT boat, on the condition the Navy loan Huckins engines and agree to look at the Huckins boat. In early July 1941, the Navy accepted PT-69.

After obtaining excellent testing results at the Plywood Derby, the Navy awarded Huckins Yacht Corporation a contract in 1941 for 8 boats, and later added 10 more. The design was enlarged and modified to meet the new requirements. The first three of the new design (PT-95 through PT-97) were initially kept in the Jacksonville, Florida, area for testing, resulting in several important modifications to the overall design (these boats were later assigned to Squadron 4 in 1942).

Huckins ended up building just two squadrons of PT boats during World War II. Five 78 ft boats were assigned to Squadron 14 (PT-98 through PT-102) which was commissioned in early 1943; and ten boats assigned to Squadron 26 (PT-255 thru PT-264) which was commissioned in mid 1943. They were assigned to specific outposts in the Panama Canal Zone, Miami, Florida, the Hawaiian Sea Frontier at Pearl Harbor and Midway, and a training center in Melville, Rhode Island.

Although not used in any other PT boat design, Huckins licensed the use of his patented Quadraconic hull in his PT boat construction. He also granted permission for Elco, Higgins, and the Philadelphia Navy Yard to use his patented laminated keel, which increased hull strength, although neither Elco nor Higgins chose to use it on their boats. Most probably due to the lateness in joining the PT boat program and unlike Elco and Higgins, the Huckins yard was not provided government support to construct a larger facility prior to the war. The handcrafted Huckins PT was produced at their civilian facility at a speed of one per month. The success and ruggedness of the Huckins' 78-foot seagoing design is demonstrated by Squadron 26's constant ready-boat operations and fleet torpedo boat training in the oceans around Midway and Hawaii during the last two years of the war.

Vosper and other types of PT boats
Vospers of Great Britain arranged for several boatyards in the United States to build British-designed 70 ft motor torpedo boats under license to help the war effort. The boatyards were located in Annapolis, Bristol, City Island, Miami, and Los Angeles. 146 boats, armed with 18 in torpedoes, were built for Lend Lease, and exported to Allied powers such as Canada, Britain, Norway, and the Soviet Union. These boats were never used by the U.S. Navy, and only about 50 were used by the Royal Navy; most were passed to other countries. The Canadian Power Boat Company produced four Scott-Paine designed PTs for the U.S. These were to be provided to the Dutch forces under Lend Lease but were re-requisitioned to the USN as PT 368–371 after the fall of the Netherlands to German forces.

Construction
PT boats offered accommodation for three officers and 14 enlisted men. Crews varied from 12 to 17, depending upon the number and type of weapons installed. Full-load displacement late in the war was 56 tons.

The hull shapes of the Elco and Higgins PT boats were similar to the contoured "planing hull" found in pleasure boats of the time (and still in use today): a sharp V at the bow softening to a flat bottom at the stern. A common characteristic of this type of contoured hull is the "rooster tail" in the wake. Unlike the actual "planing hull" Huckins, which planed at 10-11 knots, the Elco and Higgins PT boats were intended to plane at higher speeds (PT 71 and PT-103 classes at around 27 knots, and the PT-265 and 625 classes at around 23 knots).

The Elco, Higgins and Huckins companies used varying lightweight techniques of hull construction. Though often said to be made of plywood, the hulls were actually made of two diagonal layered 1 in thick mahogany planks, with a glue-impregnated or lead-painted layer of canvas in between. Holding all this together were thousands of bronze screws and copper rivets. This type of construction made it possible for damage to the wooden hulls of these boats to be easily repaired at forward operating bases by base force personnel. According to Robert McFarlane, the US Navy built the hulls of some PT boats partially from 3,000-year-old white cedar logs recovered from sphagnum bogs in New Jersey.

As a testament to the strength of this type of construction and watertight bulkheads, several PT boats withstood catastrophic battle damage and still remained afloat. For example, the forward half of future President John F. Kennedy's PT-109 (Elco) stayed afloat for 12 hours after she was cut in half by the Japanese destroyer Amagiri. PT-323 (Elco) was cut in half by a kamikaze aircraft on 10 December 1944 off Leyte, yet remained floating for several hours. PT-308 (Higgins) had her stern sheared off by a collision with PT-304 during a night mission in the Mediterranean on 9 March 1945 and yet returned to base for repairs. PT-167 (Elco) was holed through the bow off Bougainville Island on 5 November 1943 by a torpedo which failed to detonate; the boat remained in action and was repaired the next day.

In 1943, an inquiry was held by the Navy to discuss planing, hull design, and fuel consumption issues. This resulted in the November 1943 Miami test trial between two Higgins and two Elco boats, but no major additional modifications were made before the end of the war. During the war, Elco came up with stepped hull designs ("ElcoPlane") which achieved significant increase in top speed. Higgins developed the small and fast 70 ft Higgins Hellcat, which was a slight variation on their original hull form, but the Navy rejected them for full production because of increased fuel consumption and other considerations.

After the war, Lindsay Lord, who was stationed in Hawaii during the war, recorded the Navy's planing hull research and findings in Naval Architecture of Planing Hulls. It covers PT boat hull design and construction and provides hull test data as well as detailed analysis of the various PT boat designs.

Armament
The primary anti-ship armament was two to four Mark 8 torpedoes, which weighed 2600 lb and contained a 466 lb TNT warhead. These torpedoes were launched by Mark 18 21 in steel torpedo tubes. Mark 8 torpedoes had a range of 16000 yd at 36 knots. These torpedoes and tubes were replaced in mid-1943 by four lightweight 22.5 in Mark 13 torpedoes, which weighed 2216 lb and contained a 600 lb Torpex-filled warhead. These torpedoes were carried on lightweight Mark 1 roll-off style torpedo launching racks. The Mark 13 torpedo had a range of 6300 yd and a speed of 33.5 knots.

PT boats were also armed with numerous automatic weapons. Common to all US PT boats were the two twin M2 .50 cal (12.7 mm) machine guns. Early PT boats (Elco PT20 through PT44) mounted Dewandre plexiglas-enclosed hydraulically-operated rotating turrets. Almost immediately after the attack on Pearl Harbor, the Dewandre turrets were replaced on the entire PT boat fleet with open-ring twin mounts. The ring mount was designed by both Elco and Bell and designated Mark 17 Twin 50 caliber aircraft mount. Part of the Mark 17 Mod 1 and Mod 2 ring mount consisted of the Bell Mark 9 twin cradle. Another automatic weapon commonly mounted on PT boats was the 20 mm Oerlikon cannon. On early series of boats, the cannon was mounted on the stern. Later in the war, several more of these 20 mm cannons were added amidships and on the forward deck.

Forward of the chart house of some early Elco 77 ft boats (PT20 through PT44) were twin .30 cal (7.62 mm) Lewis machine guns on pedestal mounts. Beginning in mid-1943, some boats were fitted with one or two .30 cal Browning machine guns on the forward torpedo racks on pedestal mounts.

Occasionally, some front line PT boats received ad hoc up-fits, where they mounted such weapons as 37 mm aircraft cannons, rocket launchers, or mortars. When these weapons were found to be successful, they were incorporated onto the PT boats as original armament. One such field modification was made to Kennedy's PT-109, which was equipped with a single-shot Army M3 37 mm anti-tank gun that her crew had commandeered; they removed the wheels and lashed it to 2x8 timbers placed on the bow only one night before she was lost. The larger punch of the 37 mm round was desirable, but the crews looked for something that could fire faster than the single-shot Army anti-tank weapon. Their answer was found in the 37 mm Oldsmobile M4 aircraft automatic cannon cannibalized from crashed P-39 Airacobra fighter planes on Henderson Field on Guadalcanal. After having demonstrated its value on board PT boats, the M4 (and later M9) cannon was installed at the factory. The M4/M9 37 mm auto cannon had a relatively high rate of fire (125 rounds per minute) and large magazine (30 rounds). These features made it highly desirable because of the PT boat's ever-increasing requirement for increased firepower to deal effectively with the Japanese Daihatsu-class barges, which were largely immune to torpedoes because of their shallow draft. By the war's end, most PTs had these weapons.

The installation of larger-bore cannons culminated in the fitting of the 40 mm Bofors gun on the aft deck. Starting in mid-1943, the installation of this gun had an immediate positive effect on the firepower available from a PT boat. The Bofors cannon had a firing rate of 120 rounds per minute (using 4-round clips) and had a range of 5420 yd. This gun was served by a crew of 4 men and was used against aircraft as well as shore bombardment or enemy surface craft.

Gunboats
In the Solomon Islands in 1943, three 77 ft PT boats, PT-59, PT-60, and PT-61, were converted into "PT gunboats" by stripping them of all original armament except the two twin .50 cal (12.7 mm) gun mounts, then adding two 40 mm and four twin .50 cal (12.7 mm) mounts. Lieutenant Kennedy was the first commanding officer of PT-59 after its conversion. On 2 November 1943, PT-59 participated in the rescue of 40 to 50 Marines during the raid on Choiseul and a foundering landing craft (LCP(R)) which was under fire from Japanese soldiers on the beach.

Late in the war, a new electrically-powered multiple gun mounting was developed by Elco for PT boats, known as the 'Thunderbolt'. At least three different versions appear to have been built and tested; one with six .50-cal Browning M2 machine-guns and two 20 mm Oerlikon cannon, another with two .50-cal machine-guns and four 20 mm cannon and a version with just the four cannon. In mid-1944, the cannon-only version of the Thunderbolt was experimentally fitted to four operational 80 ft Elco boats which served with PTBRON 29 in the Mediterranean theatre: These were PTs 556-559. Photographic evidence shows that these boats landed their torpedoes and did not operate as torpedo craft when shipping the large and heavy Thunderbolt. According to Bulkley in chapter 18 of 'At Close Quarters' the multiple 20 mm mounting was anticipated to be "of limited usefulness" against "well compartmented F-lighters" where even the 40 mm Bofors struggled to inflict serious damage.

The weapon was trialled operationally on the nights of July 16/17 and July 18/19, when PT 558 (Ens. Aalton D. Monaghan) patrolled off the Antibes area with two regular 40 mm-armed boats and on both occasions engaged small single patrol boats; both craft were sunk by the combined gunfire of the American patrol. Lt Cmdr Daunis reported that "The Elco Thunderbolt mount has been used in two gunnery attacks and has proven to be an exceptional weapon."

Other armament
Towards the end of the war, beginning in 1945, PTs received two eight-cell Mark 50 rocket launchers, launching 5 in spin-stabilized flat trajectory Mark 7 and/or Mark 10 rockets with a range of 11000 yd. These 16 rockets plus 16 reloads gave them as much firepower as a destroyer's 5 in guns broadside (albeit without their accuracy). By war's end, the PT boat had more "firepower per ton" than any other vessel in the U.S. Navy fleet. PT boats also commonly carried between two and eight Mark 6 depth charges in roll-off racks. A few PT boats were equipped to carry naval mines launched from mine racks, but these were not commonly used.

Engines
With the exception of the experimental PT boats, all US PT boats were powered by three marine-modified derivations of the Packard 3A-2500 V-12 liquid-cooled, gasoline-fueled aircraft engine. Improvements upon Packard's World War I Liberty L-12 2A engine, the successive "M" for "marine" designated 3M-2500, 4M-2500, and 5M-2500 generations all featured slight changes and more power. Their superchargers, intercoolers, dual magnetos, and two spark plugs per cylinder reflected their aircraft origins.

Packard's licensed manufacture of the famed Rolls-Royce Merlin aircraft engine alongside the marine 4M-2500 has long been a source of confusion. Only the British-built PT-9 prototype boat brought from England for Elco to examine and copy featured a Merlin. The 4M-2500 initially generated 1200 hp. It was subsequently upgraded in stages to 1500 hp, allowing a designed speed of 41 kn. The 5M-2500 introduced in late 1945 had a larger supercharger, aftercooler, and increased power output of 1850 hp. It could push fully loaded boats at 45 to 50 kn. However, subsequent additions of weaponry offset this potential increase in top speed.

Fuel consumption of any version of these engines was exceptionally heavy. A PT boat carried 3000 USgal of 100 octane aviation fuel, enough for a 4M-2500 equipped boat to conduct a maximum 12-hour patrol. Some 200 USgal per hour were consumed at a cruising speed of 23 kn, increasing to 500 USgal per hour at top speed. Hull fouling and engine wear could both decrease top speed and increase fuel consumption materially.

Service
PT boats operated in the southern, western, and northern Pacific, as well as in the Mediterranean Sea and the English Channel.

Early use

Originally conceived as anti-ship weapons, PT boats were publicly credited with sinking several Japanese warships during the period between December 1941 and the fall of the Philippines in May 1942 —even though the Navy knew the claims were all false. The exaggerated claims by Lieutenant John D. Bulkeley, commanding officer of Motor Torpedo Boat Squadron Three (MTBRON 3), about the effectiveness of the PTs in combat against larger craft allowed him to recruit top talent, raise war bonds, and caused overconfidence among squadron commanders who continued to pit PTs against larger craft. The reality was his claims that PTs had sunk a Japanese cruiser, a troopship, and a plane tender in the Philippines were untrue.

Compounding the difficulty with the early torpedoes, PT boat crews attacking at night may have sometimes failed to note a possible torpedo failure. Although the American Mark 8 torpedo did have problems with porpoising and circular runs, it could and did have success against common classes of targets. The Mark 3 and Mark 4 exploders were not subject to the same problems as the Mark 6 exploders on U.S. submarines' Mark 14 torpedoes. Difficulties remained in spite of Bulkeley's claim that introduction of the Mark 13 torpedo to PT boats in mid-1943 all but eliminated the early problems that PT boats had with their obsolete Mark 8s. In the August 1943 engagement in which PT-109 was lost, fifteen boats shipping 60 torpedoes fired over half with no hits on an enemy vessel.

Night attacks

PTs would usually attack at night. The cockpits of PT boats were protected by armor plate against small arms fire and splinters. Direct hits from Japanese guns could and did result in catastrophic gasoline explosions with near-total crew loss. Crews feared attack by Japanese seaplanes, which were difficult to detect even with radar but which could easily spot the phosphorescent wake left by PT propellers. Bombing attacks killed and wounded crews even with near misses. There are several recorded instances of PT boats trading fire with friendly aircraft, a situation also familiar to U.S. submariners. Several PT boats, such as PT-346, were lost by friendly fire from both Allied aircraft and destroyers. Enemy forces would use searchlights or seaplane-dropped flares to illuminate fleeing PT boats.

Initially, only a few boats were issued primitive radar sets. U.S. Navy PTs were eventually fitted with Raytheon SO radar, which had about a 17 nmi range. Having radar gave Navy PTs a distinct advantage in intercepting enemy supply barges and ships at night. As more PTs were fitted with dependable radar, they developed superior night-fighting tactics and used them to locate and destroy many enemy targets.

During some of these nighttime attacks, PT boat positions may have been given away by a flash of light caused by grease inside the black powder-actuated Mark 8 torpedo tubes catching fire during the launching sequence. In order to evade return fire from the enemy ships, the PT boat could deploy a smoke screen using stern-mounted generators. Starting in mid-1943, the old Mark 18 torpedo tubes and Mark 8 torpedoes began to be replaced. The new Mark 1 "roll-off" torpedo launcher rack (loaded with an improved Mark 13 aerial torpedo) effectively eliminated the telltale flash of light from burning grease, did not use any form of explosive to launch the torpedo, and weighed about 1000 lb less than the tubes.

Solomon Islands campaign
The effectiveness of PT boats in the Solomon Islands campaign, where there were numerous engagements between PTs and capital ships, as well as against Japanese shipborne resupply efforts dubbed "The Tokyo Express" operating in New Georgia Sound (called "The Slot" by the Americans), was substantially undermined by defective Mark 8 torpedoes. The Japanese were initially cautious when operating their capital ships in areas known to have PT boats, knowing how dangerous their own Type 93 torpedoes were and assuming the Americans had equally lethal weapons.

The PT boats off Guadalcanal were given credit for several sinkings and successes against the vaunted Tokyo Express. In several engagements, the mere presence of PTs was sufficient to disrupt heavily escorted Japanese resupply activities at Guadalcanal. Squadrons (MTBRON) 2, 3, 5 and 6 would lie in wait to ambush targets from torpedo range, generally about 1000 yd. Afterwards, the PT mission in the Solomon Islands was deemed a success.

D-Day invasion
Some PT boats served during the Battle of Normandy. During the D-Day invasion, PTs patrolled the "Mason Line", forming a barrier against the German S-boats attacking the Allied landing forces. They also performed lifesaving and anti-shipping mine destruction missions during the invasion.

Barge attacks
Perhaps the most effective use of PTs was as "barge busters." Since both the Japanese in the New Guinea area and the Germans in the Mediterranean had lost numerous resupply vessels to Allied air power during daylight hours, each attempted to resupply their troop concentrations by using shallow draft barges at night in very shallow waters. The shallow depth meant Allied destroyers were unable to follow them, and the barges could be protected by an umbrella of shore batteries.

The efficiency of the PT boats at sinking the Japanese supply barges was considered a key reason that the Japanese had severe food, ammunition, and replacement problems during the New Guinea and Solomon Island campaigns, and made the PT boats prime targets for enemy aircraft. The use of PT boat torpedoes was ineffective against these sometimes heavily armed barges, since the minimum depth setting of the torpedo was about 10 feet (3 m) and the barges drew only 5 feet (1.5 m). To accomplish the task, PTs in the Mediterranean and the Pacific (and Royal Navy and Royal Canadian Navy motor torpedo boats in the Mediterranean) installed more and heavier guns which were able to sink the barges. One captured Japanese soldier's diary described their fear of PT boats by describing them as "the monster that roars, flaps its wings, and shoots torpedoes in all directions."

Although their primary mission continued to be attack on surface ships and craft, PT boats were also used effectively to lay mines and smoke screens, coordinate in air-sea rescue operations, rescue shipwreck survivors, destroy Japanese suicide boats, destroy floating mines, and carry out intelligence or raider operations.

Repair training
In 1944, several Higgins 78 ft boats (PT222, PT-283, PT-284, PT-285, and PT-282) were converted, releasing PT-59, PT-60, and PT-61 for transfer back home to the Motor Torpedo Boat Squadrons Training Center in Melville, Rhode Island, for use in training in hull repair techniques.

Boats

Many PT boats became famous during and after World War II:
 * PT-41, commanded by Ensign George E. Cox, Jr. USNR, carried General Douglas MacArthur in his escape from Corregidor Island, Philippines. Lieutenant John D. Bulkeley, commanding officer of MTBRON 3, was awarded the Medal of Honor for his operations in the Philippines before rescuing MacArthur. Bulkeley's story inspired a book and the movie They Were Expendable, which was based on it. PT-41 was the flagship of MTBRON 3, based in the Philippines in 1941–1942.
 * Life magazine published an article about the PT boat captains in the battles off Guadalcanal, featuring the exploits of Lieutenants "Stilly" Taylor, Leonard A. Nikoloric, Lester Gamble, and Robert and John Searles; the article mentioned many boats in MTB Squadrons Two and Five (in particular, PT-36, PT-37, PT-39, PT-44, PT-46, PT-48, PT-59, PT-109, PT-115, and PT-123).
 * Other PT boats gaining fame during the war were PT-363 and PT-489, the boats used by Lieutenant Commander Murray Preston to rescue a downed aviator in Wasile Bay off Halmahera Island, for which Preston was awarded the Medal of Honor.
 * PT-109, commanded by Lieutenant, junior grade, John F. Kennedy, was made famous through Robert J. Donovan's 1961 book  PT-109: John F. Kennedy in World War II and the 1963 film based on it, PT 109.
 * PT-59 was commanded by Kennedy after the loss of PT-109. Its remains have (possibly) been discovered in the Harlem River in the Inwood, Manhattan section in New York City.

Losses
According to the book "At Close Quarters: PT Boats in the United States Navy," 99 of the 531 PT boats that served during World War II were lost to various causes.
 * Accidents, friendly fire, sea conditions – 32
 * Scuttled to prevent capture – 27
 * Rammed by the enemy – 8
 * Kamikaze – 2
 * Hit naval mine – 9
 * Enemy coastal artillery – 6
 * Strafed – 8
 * Enemy naval gunfire – 7

Surviving boats
At the end of the war, almost all surviving U.S. PT boats were disposed of shortly after V-J Day. Hundreds of boats were stripped of all useful equipment and then dragged up on the beach and burned. This was done to minimize the amount of upkeep the Navy would have to do, since wooden boats require much continuous maintenance, and they were not considered worth the effort. The boats also used a lot of high octane fuel for their size, making them too expensive to operate for a peacetime Navy. Much of this destruction (121 boats) occurred at PT Base 17 on Samar, Philippines, near Bobon Point.

Production boats
A few (one 80' Elco, one 72' Vosper, and three 78' Higgins) were cut up and destroyed between 1998 and 2008, leaving (a known) total of 12 PT boats, and 2 experimental PT boat hulls in various states of repair, surviving today in the U.S.:

PT-48 is possibly the last surviving 77 ft Elco PT boat. In July 1942, PT-48 (nicknamed "Prep Tom" and "Deuce") was assigned to MTBRON 3(2). This second Squadron 3 was the first to arrive in the Solomons and saw heavy engagement with the "Tokyo Express". PT-48 was one of the first 4 boats to arrive at Tulagi on 12 October 1942. On the night of 13/14 October 1942, PT-48 engaged a Japanese destroyer at 200 yd. PT-48 is today in need of major restoration, after having been cut down to 59 ft and used as a dinner cruise boat. Because of this boat's extensive combat history, having survived 22 months in the combat zone at Guadalcanal (more time in combat than any other surviving PT boat), a preservation group, "Fleet Obsolete" of Kingston, New York, acquired and transported it to Rondout Creek in 2009 for eventual repair.
 * PT-48

One of two fully restored and operational PT boats and the only combat veteran of the two, PT-305 ("Half Hitch", "Barfly", "USS Sudden Jerk") is a Higgins 78 ft boat, assigned during the war to MTBRON-22, and saw action against the Germans in the Mediterranean Sea. Squadron 22 was operating with the British Royal Navy Coastal Forces, and saw action along the northwest coast of Italy and southern coast of France. In June 1945 the squadron was shipped to the U.S. for refitting and transfer to the Pacific, but the war ended while still in New York. PT-305 was cut down to 65 ft for use as an oyster seed boat in Crisfield, Maryland. PT-305 was acquired by the Defenders of America Naval Museum (DOANM), and then sold in May 2007 to the National World War II Museum in New Orleans. After a lengthy restoration PT-305 has been restored to a seaworthy, operational vessel. It was relaunched in March 2017.
 * PT-305

A 78 ft Higgins, PT-309 ("Oh Frankie!") was assigned during the war to MTBRON 22 and saw action against the Germans in the Mediterranean Sea. The squadron was operating under the British Coastal Forces and saw action along the northwest coast of Italy and southern coast of France. In April 1945 the squadron was shipped to the U.S. for refitting and transfer to the Pacific, but the war ended while still in New York. PT-309 was named in honor of Frank Sinatra, who the boat's commanding officer met at a nightclub shortly before MTBRON 22 left New York for the Mediterranean Theatre. PT-309 is located at the National Museum of the Pacific War in Fredericksburg, Texas, and was restored by the Defenders of America Naval Museum. PT-309 is restored (but non-operational) in a static diorama display without engines installed. Her external restoration was completed in 2002.
 * PT-309

PT-459 ("Mahogany Menace") a Higgins 78 ft boat, was assigned to MTBRON 30 on 15 February 1944. MTBRON 30 saw action in the English Channel as part of the Invasion of Normandy. In late June 1945 the squadron was shipped to the U.S. for refitting and transfer to the Pacific, but the war ended while still in New York. After the war, she was cut down to 65 ft and highly modified into a sightseeing boat and fishing trawler. She was acquired by Fleet Obsolete in June 2008 and moved to Kingston, New York, for possible restoration.
 * PT-459

PT-486, an 80 ft Elco boat, was placed in service on 2 December 1943. It was used in the training squadron MTBRON 4 in Melville, Rhode Island, during World War II until it was placed out of service 16 January 1946. In 1952 it was used as an excursion vessel from Otten's Harbor in Wildwood, New Jersey. The boat was renamed "Big Blue" and used until 2002. It is currently owned by Fleet Obsolete, with plans for possible restoration.
 * PT-486

PT-615, an 80 ft Elco originally assigned to MTBRON 42, was commissioned after the war ended. PT-615 was returned to Elco after being sold and was heavily modified into a yacht, which was leased to actor Clark Gable. He named the boat Tarbaby VI and used her through the 1950s. The boat was serviced and stored by Elco. She was sold several times, and moved to Kingston, New York for possible restoration.
 * PT-615

PT-617 is an 80 ft Elco boat located at the Battleship Cove Naval Museum in Fall River, Massachusetts. She was obtained from the backwaters of Florida and moved to its current location by PT Boats Inc. Full restoration was completed in 1989. She is available for public viewing and has portions of her hull cut away to display the cramped interior of the crew's quarters.
 * PT-617

PT-657, a Higgins 78 ft boat, has been converted into a charter fishing boat. She is located in San Diego and is now named Malihini.
 * PT-657

PT-658 is a 78 ft Higgins boat, and along with PT-305, is one of two authentically restored and operational U.S. Navy PT boats afloat today. Relaunched after hull restoration in 2005, it is located at Pier 308, Vigor Shipyard in Portland, Oregon's Swan Island Lagoon. Maintained by an all volunteer group, it is powered by the three Packard V12 5M-2500 gas engines and includes all weapons, electronics, equipment and accessories restored to appear as they did when she went into service. PT-658 was added to the National Register of Historic Places in 2012.
 * PT-658

PT-724, a surviving Vosper built at the Annapolis Boat yard in Maryland, has been used as a yacht and has since been acquired by the Liberty Aviation Museum to be restored back to its original Vosper configuration.
 * PT-724

PT-728, a surviving Vosper boat built under license at the Annapolis Boat Yard in Maryland, was restored in Key West, Florida. Her deck house was reconfigured to partially resemble an 80 ft Elco instead of its original Vosper 70 ft configuration. PT-728 was acquired by Fleet Obsolete and moved to Kingston. There PT-728 allows up to 49 tourists the chance to ride on a "PT boat". This boat is the only U.S. Coast Guard regulation-approved PT boat licensed to take passengers for hire, and the only surviving U.S.-built Vosper design. In spring of 2012, PT-728 was acquired by the Liberty Aircraft Museum of Port Clinton, Ohio, for further restoration.
 * PT-728

PT-766 is an 80 ft Elco boat that is a private yacht ("Finished Business") located in Washington D.C. She represents the final class of Elco's with significant updates to the superstructure and radar and was intended for MTBRON 44 but was cancelled due to the end of the war.
 * PT-766

PT-796 ("Tail Ender") is a 78 ft Higgins. After the war ended PT-796 was used in the Key West/Miami area for experimental purposes. She was retired from service in the late 1950s. Shortly after her retirement from service, the PT-796 was used as a float during President John F. Kennedy's inaugural parade to represent PT-109, with the PT-109 hull number painted on the bow, and several of PT-109's surviving crew members manning the boat. Today, PT-796 is located at the Battleship Cove Naval Museum in Fall River, Massachusetts, in a Quonset hut-style building, protected from the weather and up on blocks. The boat is owned by PT Boats, Inc., a World War II PT veterans organization headquartered in Germantown, Tennessee.
 * PT-796

Experimental boats
Two experimental PT boats survive, PT-3 (built by Fisher Boat Works) in New Jersey and PT-8. PT-3 was designed by George Crouch and employed lightweight planing hull construction methods. A 59 ft barrel-back (which provided increased strength to the sides and deck), a unique double longitudinal planked (mahogany outer planking and Port Orford cedar inner planking) lightweight hull on bent laminated oak framing, she was the "featherweight" of transportable PT boat design, but was later rejected by the Navy during trials in 1941 after being deemed too short to carry 4 torpedoes, as well as being able to only launch torpedoes stern first, which was a procedure considered too dangerous by BuOrd. PT-3 and PT-8 were both part of Motor Torpedo Boat Squadron 1 (MTBRON 1) during the testing period. After testing was completed, PT-3 was transferred to Canada in April 1941 under lend-lease. PT-3 served with the RCAF Fleet as the RCAF Bras d'Or M413 (B119) based at Eastern Air Command in Halifax. She was transferred back to the United States in April 1945.
 * PT-3

PT-8 (built at Philadelphia Naval Shipyard) in Louisiana was built entirely from aluminum but did not pass the speed acceptance criteria for use as a PT boat for the U.S. Navy because of its weight. She was reclassified as a harbor patrol boat (YP 110) for the duration of the war. PT-8 was stored in a yard for several decades in Baytown, Texas, but has since moved.
 * PT-8

The two Vosper boats in England were built by Vosper, and the first is in fairly good condition at Portsmouth. The second UK built boat is in private hands, floating on a canal north of London and being used as a private residence, though it is remarkably intact in its World War II configuration.
 * UK Vosper

Exported PT boats

Ten Higgins boats were delivered in 1948 for use by the Argentine Navy during the late 1940s up until the late 1970s. All of these boats are now retired from naval use, with two still in civil use today as sightseeing boats on Mar del Plata: the Leonardo da Vinci and the Mar de la Plata. The other six boats are in various states of disrepair, sunk or scrapped.

Movie stand-ins
The original 1962–66 McHale's Navy TV series used a Vosper design PT-694 Prior to starring in the television series this boat was purchased as war surplus by Howard Hughes and was used as the camera chase boat when the Spruce Goose made its only flight. The stern of the Vosper boat is visible in the footage of that event.

In John Ford's 1945 war film, They Were Expendable, two 80 ft Elcos were used during filming along with four former MTBRON 14 78-foot Huckins.

For the 1962 movie PT 109, several 82 ft USAF crash rescue boats were converted to resemble 80-foot Elcos when the few surviving boats were found to need too much work to make them seaworthy for use during the film.

title: PT boat