The remains of a WWII High Speed launch (HSL) can be found at Polbathic.
High Speed Launch
The history of this vessel is not yet known, but it is reported that she had a pennant number of 27xx where the xx is unknown. The RAF numbers for this class of vessel were 2700-2716 and 2739-2746 so it should be one of these vessels. In 2002 her wheelhouse was still attached but by 2008 it had disappeared. This boat may be the same HSL that was photographed in Hooe Lake in the 1980s .
Early in 1942, the RAF Marine Craft Policy Committee accepted both Thornycroft and Vospers designs for new HSLs. Whilst the aforementioned concentrated on their tried and tested hull designs, George Selman at BPBC was able to adopt a more expansive approach. He was able to conceive an original design which was close to the RAF ideal. The result was the 68ft BPB HSL, also known as the BPB Type 3 HSL, but nicknamed the "Hants & Dorset". The new HSL was a big and beamy craft in comparison with all other HSLs, and the interior was palatial after the confined spaces of the other types. The amount of space was further enhanced by the designer's concept of placing a full height deckhouse above the main deck instead of the customary half-height, recessed deckhouse. Apart from the engine room, which was separated from the forward sections by the tank space, all working and accommodation areas of the craft were interconnected, hence the crew were able to move from any part of the deckhouse, via hatch and ladder to any part of the lower deck without venturing outside.
The hull design was advanced for its day; the chines were lifted at the forward end to create a deep vee forefoot and a soft wave entry, twisting to an almost flat planning section aft. Although the 68ft HSLs did pound, they were more comfortable than the BPB 63ft HSLs. They were also slower than the 63ft craft, but could hold a good speed in rough sea.
HSL 2552, the first of the type, arrived at Calshot in October 1942 and after gaining the confidence of RAF crews many more were ordered and built. A total of 90 of the type were eventually built at Hythe and Poole between 1942 and 1946. Construction gained great pace in 1943 when 69 craft of the type were completed. The last two craft were completed in 1946, however in 1944 a reassessment of requirements led to cancellation of an order for a further 32 craft originally allocated numbers 2747 - 2778.
The 68ft HSL was very successful, with many serving into the 1950's, the only one type of 10 wartime HSLs to be retained by the RAF in the big sell-off after VJ day. With the war over, the role of the craft was changed to that of Rescue and Target Towing and several craft were given limited or full conversions to Rescue & Target Towing Launches - RTTL Mk.1 configuration. Limited conversions involved removing the guns and glass domes, the tubs being retained, whereas in the full conversion the gun tubs and all associated fittings were removed. In both conversions a small target towing winch and cuddy were fitted aft. Four former HSLs were also converted to Remote Controlled Target Launches (RCTL), these later being converted to RTTLs.
The dimensions of the launch were 64 ft. overall with a beam of 14 ft. 6 ins., and powered by a trio of Napier Sea Lion engines. The range was 500 miles at a speed of 39 knots. The two wing engines were inclined to drive directly to the outboard propeller shafts, whilst the centre engine faced the opposite direction and transmitted via a Vee-drive to the centre propeller. This arrangement allowed for “cruising” on the centre engine only, a range-extending economy measure which retained a high degree of manoeuvrability. The accommodation included an officer’s wardroom/sickbay for four and forecastle bunks for eight crew.
Vessel type information from Boats of the Royal Air Force Marine Branch 1918 - 1986 .
The remains of the hull of this HSL lies in amongst saltings, the deck superstructure is gone and the hull itself is in a poor state.
Thanks to Jan Carpenter for the additional information.
Polbathic Turf, the saltings at the entrance to Polbathic Lake on the south side.
Last updated 18 Apr 2021
Position OS: SX 36056 56830
Position GPS: 50.388448, -4.307605
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British Power Boat Company, Hythe, Southampton
Timber, diagonal planked, mahogany
Originally 3 x Napier Sea Lion engines
13.5 tons displacement
High Speed Launch 102
High Speed Launch (HSL) 102, commissioned in 1936, is the only 100 class high speed, air/sea rescue launch to survive. See the HSL 102 page on the Portsmouth Naval Base Property Trust website.
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