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A PT boat (short for ''Patrol Torpedo boat'') was a torpedo-armed fast attack craft 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 by ineffective torpedoes, limited armament, temperamental airplane engines, and comparatively fragile construction that limited it to coastal waters. The PT boat was very different from the first generation of torpedo boat, which had been developed prior to World War I and featured a "displacement" hull. It rode low in the water, displaced up to 300 tons, and had a top speed of . Instead, World War II PT boats exploited advances in planing hull design borrowed from offshore powerboat racing to reduce displacement to only 30–75 tons and increase top speed to , with a corresponding improvement in mobility. During World War II, PT boats engaged enemy warships, transports, tankers, barges, and sampans. As gunboats they could be effective against enemy small craft, especially armored barges used by the Japanese for inter-island transport. Primary anti-ship armament was four 2,600 pound (1,179 kg) Mark 8 torpedoes. Launched by 21-inch Mark 18 (530 mm) torpedo tubes, each bore a 466-pound (211 kg) TNT warhead and had a range of 16,000 yards (14,630 m) at 36 knots (66 km/h). Two twin M2 .50 cal (12.7 mm) machine guns were mounted for anti-aircraft defense and general fire support. Some boats shipped a 20 mm Oerlikon cannon. Propulsion was via a trio of modified Packard 3A-2500 V-12 derived aviation gasoline-fueled, liquid-cooled aircraft engines. Nicknamed "the mosquito fleet" – and "devil boats" by the Japanese – the PT boat squadrons were heralded for their daring and earned a durable place in the public imagination that remains strong into the 21st century. ==History== The first mention of high speed motor boats for the US Navy was in 1916 when a Michigan boat designer offered to build in numbers for $20,000 each, a 55 mph boat, that mounted on the bow a torpedo and two machine guns. Nothing became of this private offer.〔(First offer to US Navy of Cheap motor Torpedo Boat ).〕 But as early as 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.〔("Navy Acquires Small Speedy Torpedo Boats" ) Popular Mechanics, Oct 1922, pp. 497–498〕 The larger boat was used for experiments until 1930. In 1939, the U.S. Navy renewed their investigation into the concept by requesting competitive bids for several different types of motor torpedo boats. This competition led to eight prototype boats built to compete in two different classes. The first class was for boats, and the second class was for boats. The resulting PT boat designs were the product of a small cadre of respected naval architects and the Navy. On 11 July 1938, invitations to builders and designers were issued with prizes awarded for the winning PT boat designs. On 8 June 1939, contracts were let to the Fogal Boat Yard, Inc., later known as the Miami Shipbuilding Co., of Miami, Florida, for ''PT-1'' and ''-2'' "Crash Boats",〔(Former Site of Miami Shipbuilding Corporation (Miami) ). Wikimapia.org.〕 and to the Fisher Boat Works, Detroit, Michigan, for ''PT-3'' and ''-4''.〔("Fast Patrol Boat Mounts Heavy Armament", September 1940, ''Popular Science'' ). Books.google.com.〕 These four boats were essentially the Crouch design, modified in some details by the Bureau of Ships. Then were the three boats built by Andrew Higgins of Higgins Industries in New Orleans. These boats were ''PT-5'' and ''PT-6'' (built using government-required Sparkman and Stephens design, scaled to an overall length of ) and then ''PT-6 "Prime"'' which was redesigned by Andrew Higgins personally using his own methods. Later that same year, Higgins was to build ''PT-70'' (at their own expense) that incorporated slight improvements over ''PT-6 Prime''. The Philadelphia Navy Yard simultaneously began construction of two other boats (''PT-7'' and ''PT-8''), created by designers at the Navy Yard and the Navy Bureau of Ships. These boats were constructed mainly out of aluminum and had 4 engines. 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, and before the end of this initial design competition, Henry R. Stuphen 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 design (''PV70'') (later renamed ''PT-9''), designed by 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''.〔Bulkley p44〕 The final PT boat design competitor was Huckins Yacht Corporation of Jacksonville, Florida. 11 October 1940, an agreement between the Navy and Huckins 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 boat (designated MT-72) was a boat that became ''PT-69''. (Huckins reported a profit of $28.60 on this transaction.) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「PT boat」の詳細全文を読む スポンサード リンク
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