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100-747: 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

200-508: A 20 mm (0.79 in) 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

300-411: A 466-pound (211 kg) TNT warhead. These torpedoes were launched by Mark 18 21-inch (530 mm) steel torpedo tubes . Mark 8 torpedoes had a range of 16,000 yards (14,630 m) at 36 knots (67 km/h; 41 mph). These torpedoes and tubes were replaced in mid-1943 by four lightweight 22.5-inch-diameter (570 mm) Mark 13 torpedoes , which weighed 2,216 pounds (1,005 kg) and contained

400-817: A 50-foot (15 m) "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-foot (12 m) sea sled capable of carrying

500-522: A 6-pdr gun. Although 10 tons heavier after conversion they still made 39 knots. Built as a private venture, the 45-ft MTBs were scaled down versions of larger Vosper design and intended to be carried by larger vessels. As MTB 104 to 107, these were taken up by Admiralty but found to be poor seakeeping and not used for combat. MTB 105 was carried aboard the Special Service Vessel HMS Fidelity after her conversion to

600-603: A 600-pound (270 kg) 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 6,300 yards (5,800 m) and a speed of 33.5 knots (62.0 km/h; 38.6 mph). 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

700-526: A Commando carrier for service in the Far East with T Company, 40 Commando . Fidelity was topedoed and sunk with great loss of life as part of Convoy ON 154 . The eight crew of MTB 105, along with two from one of Fidelity's floatplanes were the only survivors from the sinking. Although various boat lengths were produced by Vosper for the Royal Navy, the "70 ft" boat was produced from 1940. The design

800-610: 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-foot (24 m) boats were assigned to Squadron 14 ( PT-98 through PT-102 ) which

900-550: A design by Fleming Jenkin , but it was not very successful. Thornycroft's design was much closer to what the navy wanted, with its low silhouette, silenced engines and shallow draught . Designated ALC No 2, it was 41 ft 6 in (12.6 m) long overall and driven by two Ford V8 engines of 65 brake horsepower (48 kW) each. The design was slightly modified by the Admiralty and some 1,929 were built during World War II. In 1944 sixty were being built each month. The LCA

1000-500: A design by John Thornycroft (the elder) who continued working with hull designs at his home on the Isle of Wight until his death in 1928, taking out his last patent in 1924. His daughter, naval architect Blanche Thornycroft worked alongside him (and after his death) testing models, calculating and recording results. The construction of smaller boats did not move to Woolston, but to a new yard ( Hampton Launch Works ) on Platt's Eyot in

1100-478: A full load. Armament was two 21 in (533 mm) torpedo tubes ; depth charges, machine guns and 20mm Oerlikon were trialled on her. MTB 102 was the fastest wartime British naval vessel in service. She was at Dunkirk in 1940 for the evacuation of British and French troops , where she served as Rear-Admiral Frederic Wake-Walker 's flagship after the destroyer HMS Keith was sunk. She carried Winston Churchill and Dwight Eisenhower when they reviewed

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1200-422: A full loaded weight of 56,000 lb (25,000 kg), C-378 made a top speed of 37 kn (69 km/h; 43 mph) with 1,400 horsepower (1,000 kW), and maintained an average speed of 34.5 kn (63.9 km/h; 39.7 mph) in a winter northeaster storm with 12-to-14-foot (3.7 to 4.3 m) seas, which would still be considered exceptional even 100 years later. The sea sled did not surface again as

1300-594: A group of industrialists headed by William Beardmore bought into the company, and they provided much of the financing when it was transformed into the public company John I. Thornycroft and Co. Ltd in 1901, with Beardmore as chairman. William Beardmore's interest in the company proved rather short-lived and he resigned as chairman in 1907. The management team of the new company consisted of John Thornycroft's son, John Edward Thornycroft as manager, and John Donaldson's son, Thornycroft Donaldson (ca. 1883–1955) as technical director. The first ship built by Thornycrofts for

1400-516: A heavier gun armament at the expense of two torpedo tubes. Boats produced to this design carried pennant numbers MTB 380-395 and MTB 523-537. The Type II did not enter service before the end of the war but was in use after the war. The first two (MTB 24, 25) were actually 74 ft prototypes for the design ordered in 1938. Powered by three Isotti-Franschini engines they could reach 37 knots. The later ones, MTBs 49-56, had four Thornycroft RY12 engines but were too slow for operations. A development of

1500-644: A profit of $ 28.60 on this transaction. 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-foot (2.4 to 3.0 m) 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

1600-472: A single 18-inch Whitehead Mark 5 torpedo . In February 1915, this Hickman sea sled demonstrated 35 kn (65 km/h; 40 mph) 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

1700-582: 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,

1800-704: 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

1900-559: 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. Vospers of Great Britain arranged for several boatyards in the United States to build British-designed 70 ft (21 m) motor torpedo boats under license to help

2000-470: A test run of the destroyer X 2 under the Hammersmith Bridge and out into the open sea. The Church Wharf, Chiswick yard finally closed in August 1909. In the years at Chiswick, John Thornycroft increasingly concentrated on the design and development part of the enterprise, while his brother-in-law since 1872, John Donaldson (1841-1899), managed the commercial side. When Donaldson died in 1899,

2100-492: 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-foot (14 m) and 55-foot (17 m)—of British Royal Navy Coastal Motor Boats were obtained for testing. The larger boat was used for experiments until 1930. In 1938,

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2200-558: A total of 18) in 1936. These entered service as MTB numbers 1 to 12 and 14 to 19. In the early days of the war, they were painted with different numbers and photos distributed to the press to give the impression the Royal Navy had more than they actually did. One photo was sent to the American monthly Popular Science showing the number twenty-three. Initially ordered as an MGB in 1941; they were converted to MTBs (412-418, 430-432, and 534-500) from 1942 by addition of two 18-inch tubes and

2300-677: A variety of motor launches (MLs), motor torpedo boats (MTBs), motor gunboats (MGBs) and motor anti-submarine boats (MASBs), which were operated by Coastal Forces . A similar size boat with a different role in the Second World War was the BPB 63 ft (19 m) high-speed launch used by the RAF for air-sea rescue operations. Diesel-powered MTBs entered the Royal Navy with the Dark class and Gay class fast patrol boats in 1954. The last MTBs in

2400-487: 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-foot (21 m) 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

2500-582: 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

2600-701: The Canadian Power Boat Company , and used by the Royal Canadian Navy 29th MTB Flotilla . Originally designed as motor gun boats (MGBs), carrying a 6-pounder (57mm, 2.24 inch) to engage enemy small craft, they were re-designated MTBs. Scott-Paine type G 70 foot boat After the end of World War II a number of Royal Navy vessels were stripped and sold for use as houseboats. These included MGBs as well as MTBs. Many of these were moored in maritime locations such as Chichester Canal ( MTB 71 , now restored and on display at

2700-598: 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,

2800-601: The 77 ft (23 m) Elcos had been found defective, and it was probable the extended 70 ft (21 m) 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. 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

2900-516: 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

3000-671: 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, testing revealed shortcomings that had to be fixed before

3100-559: 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

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3200-479: 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

3300-589: 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 and his innovative Quadraconic planing hull design were latecomers to PT boat design. Not invited to participate in

3400-525: 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

3500-602: The Huckins 72-foot (22 m) boat, was third with an average speed of 33.83 kn (62.65 km/h; 38.93 mph); PT-6 , the Higgins 81-footer, with an average speed of 31.4 kn (58.2 km/h; 36.1 mph) was fifth; and PT-8 , the Philadelphia Navy Yard boat, was last, at 30.75 kn (56.95 km/h; 35.39 mph). The other two Elco boats, PT-30 and PT 23 (standby boat), followed PT-31 , placing before PT-69 . The accelerometers ranked

3600-555: 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 of which had a 466-pound (211 kg) TNT warhead and a range of 16,000 yards (15,000 m) at 36 knots (67 km/h). 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

3700-558: 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

3800-627: 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

3900-421: 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-foot (22 m) boat (designated MT-72) later became PT-69 . Huckins reported

4000-547: 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 (25 mm) 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

4100-425: 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

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4200-556: The Royal Naval Museum in Gosport ), Langstone Harbour , Littlehampton , Hayling Island and Wootton Creek , although most have now disappeared from these locations. More MTB houseboats can be found at Shoreham-by-Sea (West Sussex), Cobden Bridge (Southampton) and Bembridge (Isle of Wight). John I. Thornycroft %26 Company John I. Thornycroft & Company Limited , usually known simply as Thornycroft ,

4300-622: The Royal Navy at the Woolston Yard was the Tribal-class destroyer HMS  Tartar . Up to the start of World War I , the yard built 37 destroyers for the Royal Navy and several more for other navies. During the war, the yard made 26 destroyers, 3 submarines and a large number of smaller craft for the Royal Navy. Notable among the smaller craft were the Coastal Motor Boats (built at Hampton – see below), based on

4400-416: The Royal Navy were the two Brave-class fast patrol boats of 1958, which were capable of 50 knots (93 km/h). Many boats were designated MTBs. A variety of designs were adopted and built. For instance, a 55 ft (17 m) type, capable of 40 kn (46 mph; 74 km/h), was shown in 1930. The following is an incomplete list of British motor torpedo boats: Commander Peter Du Cane CBE ,

4500-792: The Second World War were called S-boote ( Schnellboote , "fast boats") by the Kriegsmarine and " E-boats " by the Allies. These large craft (well over 100 ft overall) were not known as motor torpedo boats at the time, but later have been grouped with them by some. Italian MTBs of this period were known as Motoscafo Armato Silurante (" MAS boats ", torpedo-armed motorboats). French MTBs were known as vedettes lance torpilles ("torpedo-launching fast boats"). Soviet MTBs were known as торпедные катеры ( torpyedniye katyery ; "torpedo cutters", often abbreviated as TKA ). Romanian MTBs were known as vedete torpiloare ("torpedo fast boats"). The role of

4600-537: 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

4700-521: The Thames at Hampton . The construction on Platt's Eyot included yachts and – during the two world wars – a large number of small vessels for the Royal Navy. The yachts included Enola (1928), Estrellita (1934) (now called Rake's Retreat ), Aberdonia (1935), and Moonyeen (1937). The pre-war motor yacht Prunella may also have been built at Hampton. These four have survived and are now recorded on National Historic Ships' National Register . In

4800-567: 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. 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

4900-402: 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-foot (16 m) boats, and the second class was for 70-foot (21 m) boats. The resulting PT boat designs were

5000-467: The Vosper designs, White had been building under sub-contract. After construction passed to Polish Navy as S5-S10. Armed with two 18-inch torpedoes, 6-pounder gun forward, twin 20mm Oerlikon aft and two twin .303 machine gun mountings. The Fairmile D was a very large British MTB designed by Bill Holt and conceived by Fairmile Marine for the Royal Navy. Nicknamed "Dog Boats", they were designed to combat

5100-516: The West Coast as part of an experiment and as a proof of concept. Higgins Industries produced 199 78 ft (24 m) 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 (24 m) Elco boats. Many Higgins boats were sent to

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5200-696: The above recommendations and their order of merit. Those are: The newly designed 80 ft (24 m) 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 8 in (6.30 m) 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

5300-570: 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

5400-793: 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. Because of the problem with ingot loading, a 185 nmi (343 km; 213 mi) 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 (4.9 m). All except

5500-408: 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-foot (23 m) 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

5600-553: The company were absorbed by Babcock International who retained the UK and international operations, but sold the US based operations to the American Jordan Company , who took the name VT Group . John Isaac Thornycroft had shown shipbuilding ability when, aged 16, he began building a small steam launch in 1859. The vessel was named Nautilus and in 1862 it proved to be the first steam launch with enough speed to follow

5700-607: The company. In 1962, John I. Thornycroft and Sons was building wooden yachts in Singapore. In 1966, Thornycrofts merged with Vosper & Company , part of the David Brown Group, to form one organisation called, by 1970, Vosper Thornycroft. The merger made sense, because Thornycroft had yard space but few orders, while Vosper had the orders but lacked space. The combined company built new facilities at Woolston and production continued there until 2004. However, by 2003,

5800-471: The contenders in the University race . The ensuing publicity prompted his father, the sculptor Thomas Thornycroft , to purchase a strip of land along the Thames at Chiswick in 1864, and that became the start of John I. Thornycroft & Co. In its first ten years the yard had a very modest production, mostly building steam launches and steam yachts . The breakthrough came in 1873, when the firm built

5900-510: 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 (73.56 km/h; 45.71 mph); followed by PT-31 , with an average speed of 37.01 kn (68.54 km/h; 42.59 mph); PT-69 ,

6000-469: 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

6100-622: The designs could meet 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

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6200-621: The early 20th century, shortly before the beginning of the First World War . Known as coastal motor boats , these were only around 15 long tons (15 t). They were joined by the Italian Navy's MAS boats , of 20–30 long tons (20–30 t) displacement. MAS 15 was the only motor torpedo boat in history to sink a battleship, the Austro-Hungarian vessel Szent István in 1918. In the Second World War, Britain fielded

6300-510: 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

6400-418: 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-foot (21 m) 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

6500-640: The fleet before the Invasion of Normandy in 1944. They were based on the British Power Boat Company Type Two 63 ft HSL ( high-speed launch ) originally designed for the Royal Air Force for air-sea rescue but reduced to 60 ft (18 m) in length. They could carry two 18-inch (457 mm) torpedoes and achieve a maximum speed of 33 kn (38 mph; 61 km/h). The Royal Navy ordered their first (of

6600-761: The following boats: 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 (53 cm) torpedoes and sufficient fuel to operate 500 NM at 20 knots; and fully loaded with two 21 in (53 cm) torpedoes and ten 300 lb (140 kg) depth charges with sufficient fuel to operate 500 nmi (930 km; 580 mi) at 20 kn (37 km/h; 23 mph). Boats would have their tactical parameters of each design determined by photographs from an airship. Lastly, there

6700-482: The following recommendations: 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

6800-420: The former Oswald Mordaunt yard at Woolston was acquired from Mordey, Carney & Co, and production of larger ships gradually moved there. At its peak, the yard at Chiswick employed 1,700 men. The production of destroyers at the yard caught the imagination of the writer H. G. Wells , who let George Ponderevo, main character of the book Tono-Bungay , become a destroyer designer in the last chapter, describing

6900-399: 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

7000-402: 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

7100-406: The inter-war years there was still some construction for the Royal Navy at Woolston, but the yard also built civilian ships, like the ferry SS  Robert Coryndon for Uganda in 1930. She apparently still survives, but as a half-submerged wreck on the shore of Lake Albert . When World War II broke out, production was stepped up again, and the yard built corvettes and destroyers. Production

7200-778: The known advantages of the German E-boats over previous British coastal craft designs. Larger than earlier MTB or motor gun boat (MGB) designs, the Fairmile D was driven by four Packard 12-cylinder 1250 horsepower supercharged petrol engines and could achieve 29 knots (54 km/h; 33 mph) at full load. The boat carried 5,200 gallons of 100 octane fuel for a range, at maximum continuous speed, of 506 nautical miles. Armament varied according to role but could include four 18-inch or two 21-inch torpedoes, 6-pounder and 2-pounder guns, Oerlikons, multiple machine guns and depth charges. These boats were designed by Hubert Scott-Paine for

7300-494: The managing director of Vosper Ltd , designed a motor torpedo boat as a private venture in 1936. She was completed and launched in 1937. The vessel was bought by the Admiralty and taken into service with the Royal Navy as MTB 102. The installed powerplant of three Isotta Fraschini Asso V-18 57-litre petrol engines delivered 3,300 hp (2,500 kW) which gave her a speed of 48 kn (55 mph; 89 km/h) light and 43 kn (49 mph; 80 km/h) when carrying

7400-544: The motor torpedo boat has been absorbed in modern navies by the fast attack craft . Torpedo boats were designed for missions that variously involved high speed, operating at night, low speed ambush, and manoeuvrability to allow them to get close enough to launch their torpedoes at enemy vessels. With no significant armour, the boats relied upon surprise and agility at high speed to avoid being hit by gunfire from bigger ships. The Royal Navy started developing particularly small, agile, and fast petrol -powered torpedo boats in

7500-498: The nineteenth century; on the contrary, the customers queued up. The original boats had locomotive-type boilers but, like its competitors, the company developed a water-tube boiler , patented in 1885 and providing more speed. The size of the vessels grew steadily, exceeding 100 tons with Ariete , delivered to Spain in 1887 and 200 tons in the Daring -class torpedo-boat destroyers of the Royal Navy. The largest vessel built at Chiswick

7600-528: 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

7700-651: 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. The Elco 77-Footer Design Demonstrates: The Huckins 72-Foot Design Demonstrates: The Navy Yard Philadelphia 81-Foot Design Demonstrates: The Higgins 81-Foot Design Demonstrates: The Higgins 76-Foot Design Demonstrates: The board arrived at

7800-471: The product of a small cadre of respected naval architects and the Navy. On 11 July 1938 the Navy solicited design proposals for 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

7900-551: 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

8000-592: The small steel torpedo craft Rap for the Navy of Norway , followed by similar boats for other navies, and by HMS  Lightning for the Royal Navy in 1877. Torpedoes and torpedo boats were seen as weapons of the future and throughout the 1870s and 1880s the Thornycroft yard became a major supplier to a number of navies. As Banbury put it: No high-pressure salesmanship was needed to sell torpedo-boats in

8100-546: The specific designation "motor torpedo boat", abbreviated to "MTB", is generally used for craft of the Royal Navy (RN) and Royal Canadian Navy boats. During the Second World War , the US Navy built several classes of marine V-12 -powered PT boat , whose hull classification symbol "PT" stood for "patrol, torpedo", but which were grouped into motor torpedo boat squadrons. German diesel-powered torpedo boats of

8200-540: The war effort. The boatyards were located in Annapolis, Bristol, City Island, Miami, and Los Angeles. 146 boats, armed with 18 in (460 mm) 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

8300-481: The war years was the fast minelayer HMS  Latona of 2,650 tons, with turbines capable of 72,000 shaft horsepower (53,690 kW) and a speed of 40 knots (74 km/h; 46 mph). The first seaworthy Assault Landing Craft (ALC), later renamed LCA, Landing Craft Assault , ordered built for the British Navy were by Thornycroft. The first prototype ALC No 1 was built by J. Samuel White of Cowes to

8400-733: The war's end, most PTs had these weapons. Motor torpedo boat A motor torpedo boat is a fast torpedo boat , especially of the mid 20th century. The motor in the designation originally referred to their use of petrol engines, typically marinised aircraft engines or their derivatives, which distinguished them from other naval craft of the era, including other torpedo boats, that used steam turbines or reciprocating steam engines . Later, diesel -powered torpedo boats appeared, in turn or retroactively referred to as "motor torpedo boats" for their internal combustion engines , as distinct from steam powered reciprocating or turbine propulsion. Though other navies built similar petrol-powered craft,

8500-514: 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,

8600-638: Was a British shipbuilding firm founded by John Isaac Thornycroft in Chiswick in 1866. It moved to Woolston , Southampton , in 1908, merging in 1966 with Vosper & Company to form one organisation called Vosper Thornycroft . From 2002 to 2010 the company acquired several international and US-based defence and services companies, and changed name to the VT Group. In 2008 VT's UK shipbuilding and support operations were merged with those of BAE Systems to create BVT Surface Fleet. In 2010 remaining parts of

8700-462: 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 (350 km; 220 mi) 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

8800-502: 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

8900-453: Was also used in other navies, such as Romania 's, which acquired three in 1939, with NMS Viscolul the lead ship of the class. Between 1943 and 1945, the "Vosper 73ft" design appeared; this was a flush-decked type with a slight sheer forward, dispensing entirely with the low forecastle and scalloping of the majority of '70-footer' types. The type II differed from the Type I in that it carried

9000-459: Was assigned as a pace boat with PT-8 in order to generate a pounding comparison. The average speed results from the 185 nmi (343 km; 213 mi) course were: Elco 77-footer ( PT-21 ), 27.5 kn (50.9 km/h; 31.6 mph); Higgins 76-footer ( PT-70 ), 27.2 kn (50.4 km/h; 31.3 mph); Higgins MRB and Philadelphia Navy Yard boat ( PT-8 ), 24.8 kn (45.9 km/h; 28.5 mph). Accelerometers were again installed in

9100-702: 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

9200-644: Was delayed by several bombings, probably influenced by the yard's proximity to the Spitfire -building Supermarine factory, also situated in Woolston. That factory was bombed extensively in the beginning of the war, and Thornycroft's yard received its fair share of the bombs. Among the more notable ships built by the yard in the war years were the two Hunt-class destroyer escorts, HMS Bissenden and HMS  Brecon , (Type IV) with better stability than their sisters . The largest naval vessel built at Woolston during

9300-454: 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

9400-404: 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

9500-443: Was produced with modifications as MTBs 31-40, 57-66, 73-98, 222-245 and 347-362. Using three Packard V1-12 marine engines , they were capable of around 37 kn (43 mph; 69 km/h). Early models carried two 21-inch (533 mm) torpedo tubes , twin 0.50 in (13 mm) machine guns in a "bin" behind the bridge and two 0.303 in (7.7 mm) machine guns. They could also carry four depth charges . The Vosper 70

9600-574: Was reasonably seaworthy, so long as waves were less than 5 ft (2 m) high. In heavy seas the situation could become critical and a number of LCAs converted to support craft disappeared in the choppy seas of D-Day , 6 June 1944. In 1944 267 were lost (out of 371 losses during the whole war). In 1955, the company built Scillonian , a passenger ferry built for the Isles of Scilly Steamship Company . In July 1960 John Ward Thornycroft , John Edward Thornycroft's son, replaced his father as chairman of

9700-415: Was replaced in the U.S. Navy by fast attack craft . 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

9800-521: 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. The primary anti-ship armament was two to four Mark 8 torpedoes , which weighed 2,600 pounds (1,179 kg) and contained

9900-526: Was the Alarm -class torpedo gunboat Speedy of 810 tons. During the 1890s it became increasingly difficult for the new vessels to pass under the Hammersmith Bridge – masts and funnels had to be lowered or removed, and put back in place again further down the Thames, and if something went wrong during trials and the boat had to return to the yard, then the whole process had to be reversed. In 1904

10000-572: 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 (46 to 50 km/h). 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 kn (74 km/h)) and corresponding torpedo tactics, but these projects were all quickly disbanded after

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