Fast Attack Boats

 

Briefing
written by
James Davies

 

VTB7

 

Key Information

Country of Origin: France
Manufacturers: Société Silbur, Ateliers et Chantiers de la Loire , Chantiers Navals de Meulan, and Chantiers Jouett, Excelsior, Jeannin, Wisner
Major Variants: VTA, VTB
Role: Fast attack craft
Operated by: French Navy
First Laid Down: 1926
Last Completed: 1939?
Units: VTA2 to VTA4; VTB2 to VTB12; VTB13 to VTB22 not completed
 

Overview

The French fast attack boat programme began after the end of the First World War, influenced by the success of the Italian and the British boats. In France these boats are known as Vedette Torpilleur, commonly shortened to VT, and with an ‘A’ appended for smaller boats and ‘B’ for larger boats they are classified as either VTA or VTB.

They began in 1921 by buying two boats from the British, one 45’ boat (VTA1) and one 55’ boat (VTB1) made by Thornycroft, to use for trials, and these boats were the basis for the first French series of boats (VTA2 to 4 and VTB2 to 7).

The three small VTA boats were built by three different French yards (Excelsior, Jeannin and Wisner) in 1929, and were very similar to the Thornycroft 45’ boat bought in 1921. They made 37 knots with a 500 hp Lorraine aircraft engine on a 5.4-ton hull, and carried one stern-launched 45-cm torpedo. They were not a success, particularly with respect to their seakeeping, and no more ‘A’ boats were built.

As with the VTAs, the six larger VTB boats were similar to the 55’ Thorneycroft boat. They were developed by two French yards (Ateliers et Chantiers de la Loire and Wisner) and entered service in 1930. The boats built by the Wisner yard had two 500-hp Lorraine engines, but at 10.1 tons they were nearly twice as heavy as the VTAs and their top speed was an identical 37 knots. The Ateliers et Chantiers de la Loire boats were similar, but used 1100-hp Lorraine engines, giving them 44 knots on trials. The increased size of the VTBs brought with it a greater punch, and they carried two 45-cm torpedoes. Unfortunately, as with the smaller ‘A’ boats, the French naval authorities were not happy with their seakeeping and the design was not continued.

Abandoning their previous reliance on designs based on British boats, the French went for a new home-made design from Société Silbur. Two boats were built (VTB8 and 9) with a similar specification, designed for 46 knots on Lorraine engines and with two side-dropping torpedoes. Unladen, VTB8 made nearly 52 knots on trials, although VTB9 broke up and sank when travelling at full speed off Barfleur in August 1939, raising questions about whether too much strength was sacrificed for speed. Problems also existed with their torpedo dropping equipment, and no more boats were built on these designs.

To date, all the French boats had been planing vessels, with a stepped hull. A stepped hull form has a round bottom with a sharp discontinuity (step) in the bottom, where the depth of the hull behind the step is several inches less than the hull in front of the step. The British, Germans and Italians had begun experimenting with a ‘hard chine’ hull form. A hard chine hull has a ‘V’ shape, with a sharp edge where the side of the hull meets the top of the ‘V’ (there are thus two sharp edges – one at the side of the boat and one on the bottom of the ‘V’). The hard chine form slightly reduced the maximum speed of the boat, but significantly improved the seakeeping qualities and manoeuvrability.

An Anglo-French prototype boat, 40K, used the hard chine design and several were sold to the Spanish Republicans during the Civil War. These made 40 knots, and were armed with two 20-mm cannons, two 53.3-cm torpedoes and 12 depth charges. The French navy considered buying some, but decided not to as the engines, although a French design, were no longer being made in France (they were made in Britain under licence).

VTB10 was designed and built by Ateliers et Chantiers de la Loire, and intended to make 45 knots at 21 tons with four 650-hp Hispano-Suiza engines and two side-dropping torpedoes. Unladen, the boat made 55 knots on trials. VTB11 and 12 were similar, apart from their engines which were dual 1100-hp Lorraine engines.

The final series of French designed and built boats, VTB13-22, followed the same basic design as VTB10. These were to be built by Ateliers et Chantiers de la Loire, Chantiers Navals de Meulan, and Chantiers Jouett, but the armistice interfered and only VTB13 and VTB14 were laid down.

18 boats were also ordered from the British, VTB23-40, and these were a British Powerboat Company design. These boats had four 45.7-cm torpedo tubes, two 13.2-mm machineguns (one each side of the bridge), eight depth charges and a smoke generator. They made 42 knots with three 1100-hp Rolls Royce Merlin engines.

The characteristics of the French-designed boats were defined by their stepped hull form – very fast in calm water, but not suited to operations in any other weather.

 

Units

Unit In Service Notes
VTA2 1929 Experimental boat, decommissioned prior to the start of the Second World War.
VTA3 1929 Experimental boat, decommissioned prior to the start of the Second World War.
VTA4 1929 Experimental boat, decommissioned prior to the start of the Second World War.
VTB2 1930 Experimental boat. Assembled in Cherburg at the start of the Second World War. Involved in the Dunkirk evacuation. Transferred from Cherburg to the UK on 18 June 1940. Laid up and decommissioned.
VTB3 1930 Experimental boat. Assembled in Cherburg at the start of the Second World War. Transferred to the air force at the start of 1940. Involved in the Dunkirk evacuation. Transferred from Cherburg to the UK on 18 June 1940 but abandoned during crossing.
VTB4 1930 Experimental boat. Assembled in Cherburg at the start of the Second World War. Involved in the Dunkirk evacuation. Transferred from Cherburg to the UK on 18 June 1940. Laid up and decommissioned.
VTB5 1930 Experimental boat, decommissioned prior to the start of the Second World War.
VTB6 1930 Experimental boat, decommissioned prior to the start of the Second World War.
VTB7 1930 Experimental boat, decommissioned prior to the start of the Second World War.
VTB8 1935 Experimental boat. Assembled in Cherburg at the start of the Second World War. Involved in the Dunkirk evacuation. Transferred from Cherburg to the UK on 18 June 1940. Requisitioned by the Royal Navy on 3 July 1940 (re-numbered B063). Transferred back to the free-French in 1941. Decommissioned in January 1944.
VTB9 1935 Experimental boat. Broke up and sank on 9 August 1939 in heavy seas.
VTB10 1937 Experimental boat, decommissioned prior to the start of the Second World War.
VTB11 1937 Transferred to UK for re-arming for anti-submarine work at the start of the Second World War. Recalled to take part in the Dunkirk evacuation unarmed apart from two machineguns. Returned to the UK to complete re-arming in June 1940, and was requisitioned by the Royal Navy in July 1940 (B064, then MGB98). Destroyed by the Luftwaffe in an attack on Gosport in 1941.
VTB12 1937 Transferred to UK for re-arming for anti-submarine work at the start of the Second World War. Recalled to take part in the Dunkirk evacuation unarmed apart from two machineguns. Returned to the UK to complete re-arming in June 1940, and was requisitioned by the Royal Navy in July 1940 (B065, then MGB99). Lost in April 1945.
VTB13 - Not completed. Damaged on slipway during an air raid in 1941. Broken up.
VTB14 1944? Completed by the French as a rescue boat. Used as a test boat until 1950.
VTB15 - Not laid down.
VTB16 - Not laid down.
VTB17 - Not laid down.
VTB18 - Not laid down.
VTB19 - Contract not signed.
VTB20 - Contract not signed.
VTB21 - Contract not signed.
VTB22 - Contract not signed.
 

Specifications

  VTA2-4 VTB2, 3 and 6
Displacement 5.3 to 5.4 tons 10.1 tons
Length 13.6 metres 15.7 metres
Beam 2.9 metres 3.0 metres
Draft 0.6 metres 0.7 metres
Propulsion 1 x 500 hp 2 x 500 hp
Speed 37 knots 37 knots
Torpedoes 1 x 45-cm stern-launched torpedo 2 x 45-cm stern-launched torpedoes
Other Weapons 1 x machinegun 1 x machinegun (?)
  VTB4, 5 and 7 VTB8 and 9
Displacement 11.3 tons 22.0 tons
Length 15.7 metres 18.85 metres
Beam 3.0 metres 4.42 metres
Draft 0.7 metres (?) 1.2 metres
Propulsion 2 x 1100 hp 2 x 1100 hp
Speed 44 knots 46 knots
Torpedoes 2 x 45-cm side-dropped torpedoes 2 x 45.7-cm side-dropped torpedoes
Other Weapons 1 x machinegun (?) 2 x machineguns
  VTB10, 13 -22 VTB11 and 12
Displacement 21.0 tons 21.0 tons
Length 20.0 metres 20.0 metres
Beam 3.96 metres 3.96 metres
Draft 1.23 metres 1.23 metres
Propulsion 4 x 650 hp 2 x 1100 hp
Speed 45 knots 45 knots
Torpedoes 2 x side-dropped torpedoes 2 x side-dropped torpedoes
Other Weapons 2 x 20-mm cannon
12 depth charges
2 x 20-mm cannon
12 depth charges