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ANGUS KONSTAM, Illustrated by TONY BRYAN
BRITISH MOTOR TORPEDO BOAT 1939-45

Vosper

The wartime success of Vosper is largely due to Commander Peter du Cane, a former naval officer and aviator who joined Vosper in 1931 to boost their involvement in high-speed craft The following year he won a controlling interest in the company and secured the contract from Sir Malcolm Campbell to build his record-breaking speedboat Bluebird II. By this stage the company was already building launches for the Royal Navy, and du Cane naturally considered tendering a bid for high-speed 'offensive torpedo boats'. The award of just such a contract to Vosper s rival, the British Power Boat Company, spurred du Cane on to develop a Vosper design, and he personally funded the design and construction of a 68-foot experimental boat with a hard-chine hull, designated PV 1 (standing for 'private venture'). It was duly purchased by the Admiralty as MTB 102. Unlike the Thornycroft and BPB designs (and after some experimentation), it was capable of firing its torpedoes from deck mounts rather than by dropping them astern. To power the craft, du Cane selected the powerful Italian Isotta-Fraschini petrol engine.

The British Power Boat Company produced a 72-foot vessel that was used as an MGB and was later converted into an MTB, the major difference being the addition of two 21-inch torpedo tubes at the sides of the bridge on the MTB, and the replacement of a 2-pounder pom-pom on the earlier MGB (shown here) with a 6-pounder on the later MTB. (Imperial War Museum)

The launch of one of the first 70-foot Vosper boats (MTB 22) at the Vosper Yard in Portsmouth. While MTB 22 was kept in service, MTB 20, 21 and 23 were sold to the Royal Rumanian Navy in 1940. (Vosper Thornycroft (UK) Ltd)

A combination of the performance of MTB 102 and the extensive lobbying of du Cane led to the award of Vosper's first real government contract. While 60-foot boats were built for foreign clients, Vosper designers also produced plans for an expanded boat, which became the 70-foot MTB. The design was an improvement, as the added length made it a better sea boat, and it also provided a more stable weapons platform. In August 1938 the Admiralty ordered four 70-foot MTBs (MTBs 20 to 23), part of a six-boat deal. The remaining craft (MTBs 24 and 25) were awarded to Thornycroft, becoming their experimental 72-foot boats. It was later decided that MTB 22 would serve as a prototype, while the remaining three Vosper boats would be sold to the Rumanian Navy. MTB 22 was handed over to the Royal Navy shortly before the outbreak of the war, but the Rumanian transfer was ordered to continue, so three replacement boats were duty ordered from Vosper (MTBs 28 to 30). The first of these would be built under contract by Thornycroft, and the remaining two by Camper 8c Nicholson, the first of many sub-contracts issued by Vosper during the war. Another experimental boat (MTB 103) was ordered from the company four months later. Additional foreign orders were also received: two 60-foot boats were ordered by Sweden (designated T3 and T4) and delivered in late 1939, while four similar boats were ordered by Norway. Of the latter, two were delivered, and two more were purchased by the Royal Navy, becoming MTBs 71 and 72. Two of these 70-foot boats were earmarked for service in the Greek Navy (also designated TS and T4), but these were also purchased by the Admiralty who designated them MTBs 69 and 70. Four replacements were duly ordered by the Greek government, and these were also impounded by the Admiralty when Greece was overrun (the boats becoming MTBs 218 to 221). In order to cope with demand, Vosper began building a new yard at Porchester towards the end of 1939.

The bridge of a late-war Vosper 73-foot boat (MTB 383) showing the ship's wheel, with the steering compass above it. To its right are (in order) the engine throttles (3), the engine telegraph, the torpedo firing levers (2) and the engine room voice pipe. The hatch and companion way to the left of the wheel leads down to the wheelhouse. (Vosper Thornycroft (UK) Ltd)

Finally at the end of 1939 Vosper was awarded the contract to build ten more 70-foot MTBs (MTBs 31 to 40). After MTB 34 the supply of Italian engines dried up, and for the remainder of the order a temporary solution was found in the Hall-Scott Defender engine. Eventually American-built Packard engines would be used in the rest of the Vosper fleet. The New Year would bring a new wave of orders. The designations MTB 41 to 56 were already provisionally allocated, so on 26 February 1940 the Admiralty ordered the production often more 70-foot boats (MTBs 57 to 66), part of an expanded programme of MTB production. Vosper designs were undergoing a change because of the need to find a reliable replacement engine. In 1941 the boats fitted with the under-powered Hall-Scott engines were refitted with American-built Packard systems, and where possible the entire fleet of 70-foot boats were re-fitted with improved 1,250hp Packard engines during 1942.

During the spring of 1940 du Cane and his design team struggled with the need to design a new type of boat built specifically around the Packard engine. When a new Admiralty contract was negotiated during April the Vosper designers proposed the introduction of a longer boat with an increased displacement, but built around three Packard engines driving three outer shafts, supported by Ford V8 engines designed to provide a silent running capability (of 6½ knots). The contract was duly approved on 14 May 1940, and work started on the first 72-foot 6-inch Vosper MTBs (MTBs 73 to 98) in September 1940. The first two entered service before the end of 1941, but delivery of the remainder was spread over a year, from January 1942 to January 1943, largely due to heavy bomb damage in Portsmouth, Of these, MTBs 78 and 79 were sub-contracted to J.S. White's Yard at Cowes; 86, 95 and 96 to Morgan Giles Yard at Teignmouth; 87 to 92 to Harland & Wolff in Belfast; and 93 and 94 to the Berth on Boat Company of Lymington, In all, 27 of the new-style Vosper boats were commissioned (actually 28, as MTB 75 was bombed on the stocks, and a new version built in its place), marking the largest single boat order of the war so far Of these, MTB 74 was a 'one-off', modified from scratch for special operations. It differed from other boats of its type, first in that it was only 70 feet long, and secondly in that its torpedo tubes were mounted on its forecastle rather than amidships. The configuration was designed to fire torpedoes over net obstructions, and the torpedoes themselves were also specially made, designed to incorporate a delay timer and an extra-large warhead.

MTB 380 was a late-war 73-foot Vosper Type I design, one of 16 boats in the class. Designed by Commander du Cane RN, these craft were amongst the best Vosper boats of the war, and their four 18-inch torpedo tubes made them far more potent than earlier craft. (Vosper Thornycroft (UK) Ltd)

MTB 358, a 72-foot 6-inch Vosper boat built in the Harland & Wolff Yard in Belfast, and attached to the 5th MTB flotilla based in Dover. It carries a single Oerlikon (protected by a splinter mattress), a twin .5-inch Vickers in a power turret aft, two 21-inch torpedo tubes and two grenade launchers mounted on the torpedo mounts. (Private collection, Museum of Naval Firepower, Gosport)

At the same time, Vosper was building four new 70-foot MTBs for the Greek Navy, but like almost all other foreign orders it was requisitioned by the Admiralty, and in December 1940 the Royal Hellenic Navy's T3 to T6 MTBs became the Royal Navy's MTBs 218 to 221, An additional order of four 72-foot six-inch boats was placed by the Admiralty in December 1940, to replace the loss of four MTBs already in service. These became MTBs 242 to 245, and followed the design of the first batch of the larger boats which were already under construction.

MTB 73 alongside the dock in the Vosper Yard, Portsmouth, in October 1941. This was the first of a batch of 72-foot 6-inch boats designed in 1940, which entered service by the end of 1941. (Vosper Thornycroft (UK) Ltd)

The next batch of 20 Vosper boats in February 1941 was the last that had to be sub-contracted exclusively to British firms. Vosper duly sub-contracted all of these 72-foot 6-inch boats. MTBs 222 to 228 were built by the H. Mclean Yard in Renfrew; MTBs 229 to 231 were produced by the McGruer Yard of Clynder; and MTBs 232 to 235 were built by the Berthon Boat Company of Lymington. MTBs 236 to 239 were built by Camper 8c Nicholson of Gosport; and MTBs 240 and 241 were built by the Morgan Giles Yard in Teignmomh. By early 1941 Vosper was hard-pressed to keep up with the demand, despite the policy of sub-contracting much of the work to smaller yards. Merchant shipping losses were mounting in the Atlantic, and therefore basic materials such as plywood, mahogany and rubber (used for non-slip decking) were all in short supply. The introduction of the Lend-Lease Act in March 1941 was a godsend for British Coastal Forces. It allowed the construction of Vosper boats under license in the United States, increased the supply of Packard and Ford engines, and allowed the US Navy to 'lend' vessels to Britain at a time when every boat was needed.

While an initial dozen Lend-Lease MTBs were supplied by either the US Navy or Elco (including MTB 258 - the BPB prototype that Scott-Paine brought to the United States), Vosper also brought over plans for their own 72-foot 6-inch boats. The first batch of 31 Lend-Lease Vosper-designed boats was contracted to two American companies: the Annapolis Yacht Yard of Maryland built MTBs 275 to 282, while the Harbor Boat Building Company of Terminal Island, California, were awarded the contract to build MTBs 297 to 306. This meant that by the summer of 1941 Vosper designers had to supervise the construction of boats on both seaboards of the United States as well as throughout Britain. Amazingly, although du Cane and his Vosper team were working at full capacity to produce these new boats, they also found time to modify older craft and to develop plans for improving their existing MTB designs.

The full involvement of the United States in the war from December 1941 brought a change in Vosper policy. While some US yards would still remain available for the production of British boats, the production of the larger yards (such as Elco and Higgins) would be increasingly geared towards the development of an American PT boat fleet. Consequently while the Annapolis Navy Yard remained committed to the production of Vosper boats under license, production in Britain would have to be increased.

Fortunately the expansion of Vosper facilities at Wyvenhoe, Porchester and Portsmouth meant that by early 1942 the company was ready to take on more projects themselves. In April 1942 the Admiralty ordered 16 more Vosper 70-foot boats (MTBs 347 to 362), whose design was similar to earlier craft but whose internal layout was improved to incorporate suggestions proposed by the crews of existing boats. This was followed by an order for 16 72-foot 6-inch boats from Annapolis. Of these, MTBs 363 to 370 were earmarked as British Lend-Lease transfers to the Soviet Union, while MTBs 371 to 378 were to be for British use.

By late 1940 most early MTBs were refitted to carry radar. In this photograph of the 72-foot 6-inch Vosper boat MTB 80, it is shown fitted with a Type 291 radar as well as IFF equipment. (Imperial War Museum)

During the year, du Cane and his team worked on plans for a new type of boat, incorporating the firepower of Motor Gun Boats with an expanded torpedo armament. This fulfilled an Admiralty requirement for a short-hulled multi-purpose MTB/MGB design, and the Vosper team worked with experienced MTB commanders and naval architects to produce what many considered to be the perfect Motor Torpedo Boat design of the war. In November 1942 the Admiralty approved the production of a 70-foot experimental boat (MTB 379) which was designed to provide a scaled-down test version of this new design. The final order of the year was for an experimental boat, and it was hoped that production of the new boats would start in the New Year. Although the experimental boat would not enter service before January 1944, the Admiralty ordered 16 vessels of the new design in March 1943. These craft (numbered MTBs 380 to 395) were given the class name of Vosper 73-foot MTB, A second contract for five more boats in December 1943 was modified to fulfil the need for a boat with a heavier gun armament. The result was the introduction of a variant of the original 73-foot Vosper design. From that point, the original batch (MTBs 380 to 395) were designated 73-foot Type I boats, and the remaining batch (MTB 523 to 527) became 73-foot Type II boats.

These new MTBs incorporated several technical innovations that made them amongst the most effective MTBs in the fleet. The latest radar and radio equipment, IFF (identify friend or foe ) and the latest echo sounders, made them the most technically advanced boats Vosper had yet produced. The Type I boats carried four 18-inch torpedo tubes, a twin 20mm Oerlikon forward, and two twin .303-inch machine guns mounted on the tops of the front torpedo tubes. When the 73-foot Type II boats appeared they only carried two 18-inch torpedo tubes, but the bow armament was substantially increased, as these vessels carried a 6-pounder Quick Firing gun in a power-driven mount and a twin 20mm Oerlikon mounted on the quarterdeck. Two twin .303-inch Lewis guns were mounted on pintles on the deck on either side of the bridge, exactly where the .303-inch mounts were on the Type I boats. The first two of the 16 73-foot Type I boats entered service shortly before the Normandy invasion (June 1944), and eight more were commissioned between July and September. Four more boats joined the fleet during the last months of the war, but MTBs 394 and 395 were commissioned after the end of hostilities. As for the Type II boats, none entered service before the end of the war.

MTB 375 photographed alongside the quay of an Italian port during early 1944. The Vosper 72-foot 6-inch boat was one of 16 Lend-Lease boats of this class built in the United States during 1943: eight served in the Royal Navy (mostly in the Mediterranean), while eight more (MTBs 363-370) were given to the Soviet Navy in early 1944. (Stratford Archive)

MTB 77 photographed at anchor somewhere on the south coast, most probably on the River Dart during 1942. It was sunk by German aircraft off the Italian coast in September 1943. (Stratford Archive)

It is also worth noting that Vosper produced several successful experimental boats, beginning with MTB 102 (Peter du Cane's private venture boat). The projected 45-foot MTB design proposed in 1939 was for use as an attack boat, carried by larger surface units, but the design was abandoned in favour of larger craft. Known as 'MTB small type', the design never entered service, as the prototype (MTB 108) was destroyed during a German bombing raid in January 1941 while still under construction. MTB 103 was an experimental 70-foot boat that was re-designated as a 70-foot target lowing boat (CT 5) when it entered service in June 1941. Finally MTB 510 was a 100-foot experimental design produced to test a new type of gearbox. Ordered in April 1942, it entered service in December 1943, but never saw active service, as it remained a test vessel based at Portland for the duration of the war.

Vosper therefore produced three main boat types during the war. The 70-foot boats were the principal boats of the early to mid-war period. Most of those which remained in service in 1942 were modified to incorporate new equipment such as radar, and in some cases the armament was improved by the addition of Oerlikons in place of twin Vickers machine guns. Although the Admiralty ordered later batches of 70-foot boats after May 1940 (when the 72-foot 6-inch design was introduced), the shorter MTB was really a pre-war design that was superseded by the larger mid-war boats. The majority of these second-generation boats entered service during 1942, by which time many of the earlier 70-foot craft were 'retrofitted' with better equipment and weapon 17. Finally the third late-war generation of 73-foot boats represented the epitome of wartime design, although only a handful saw active service before the end of the conflict. It was Vosper's ability to adapt its designs in the light of combat experience and to incorporate technical improvements that made the company the most successful MTB producer of the war.

MTB 34 was a 70-foot Vosper boat, built at the Vosper Yard in Portsmouth during 1940. Like the earlier boats of its class (MTBs 20-23 and 29-30) it was armed with twin .5-inch machine guns in bins behind the bridge, while additional smaller machine-guns were fitted as they became available. (Museum of Naval Firepower, Gosport)

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