Type Two 63 ft HSL

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Type Two 63 ft HSL, nicknamed the Whaleback, was a 63-foot high-speed rescue launch built by British Power Boats for the RAF Marine Craft Section and the Royal Navy during World War II. It replaced the 64 ft HSL and was later followed by the Type Three 68 ft Hants and Dorset.

Designed in 1937 by George Selman, the Whaleback stood out for its curved deck and humped cabin. The mahogany hull was hard-chine and planing, with a low cabin containing the wheel-house, chart room and sickbay. On top of the cabin were aircraft-style gun turrets. Armament evolved from two .303-inch machine guns to more complex layouts, including twin .303 guns and, after the Dieppe raid, a single 20 mm Oerlikon on the rear deck, plus added anti-shrapnel padding around the forward cabin.

Power came from three Napier Sea Lion engines, each producing 500 hp, giving a top speed of about 36 knots and a range of roughly 500 miles. The crew numbered nine, including the captain and a medical orderly.

In service, 69 Type Two HSLs were built between 1940 and 1942. They were used to rescue downed aircrew around the British Isles, coordinating with RAF and Coastal Command aircraft and Royal Navy rescue launches. After the war, many were transferred to the Royal Navy or Italian Air Force; most were later stored and sold as houseboats. None are in museums today.