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.[3]
British MTBs
The following is an incomplete list of British motor torpedo boats:
Vosper "private venture boat"
Commander Peter Du Cane CBE, 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.
- Length: 68 ft (21 m)
- Beam: 19 ft 9 in (6.02 m)
- Draft: 3 ft 9 in (1.14 m),
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 a full load.
- Crew: 2 officers, 10 men.
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 the fleet before the Invasion of Normandy in 1944.
British Power Boat 60 ft MTB
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).[5] The Royal Navy ordered their first (of a total of 18) in 1936.[6] 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.[7]
British Power Boat 72 ft MTB
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 a 6-pdr gun. Although 10 tons heavier after conversion they still made 39 knots.[8]
Vosper 45 ft MTB
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.[9]
Vosper 70 ft MTB
Although various boat lengths were produced by Vosper for the Royal Navy, the "70 ft" boat was produced from 1940. The design 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.[10] They could also carry four depth charges.
The Vosper 70 was also used in other navies, such as Romania's, which acquired three in 1939, with NMS Viscolul the lead ship of the class.
Vosper 73 ft (Type I and Type II)
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 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.[11]
- Type I
- Length: 73 ft (22 m)
- Engine: 3 Packard 4M V12 engines for a total of 4,200 hp
- Speed: 40 knots (74 km/h)
- Range: 470 nmi (870 km) at 20 knots (37 km/h)
- Displacement: 47 t
- Armament:
- Crew: 13
- Type II
- Length 73 ft (22 m)
- Engine 4,200 hp
- Speed 40 knots (74 km/h)
- Range 480 nmi (890 km) at 20 knots (37 km/h)
- Displacement 49 t
- Armament
- Crew 13
Thornycroft 75 ft MTB
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.[14]
J S White 75 ft MTB
A development of 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.[15]
Fairmile D MTB
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 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.[16]