|Builder:||Cammell Laird & Co Limited, Birkenhead|
|Laid down:||18 August 1943|
|Launched:||2 October 1944|
|Commissioned:||21 December 1944|
|Fate:||Sold to the Portuguese Navy in 1948 and renamed NRP Neptuno|
|Class and type:||S-class submarine|
|Length:||217 ft (66.1 m)|
|Beam:||23 ft 9 in (7.2 m)|
|Draught:||14 ft 1 in (4.3 m)|
|Range:||7,500 nmi (13,900 km; 8,600 mi) at 10 knots (19 km/h; 12 mph) surface; 120 nmi (220 km; 140 mi) at 3 knots (5.6 km/h; 3.5 mph) submerged|
|Test depth:||350 feet (106.7 m)|
Design and description
The last 17 boats of the third batch were significantly modified from the earlier boats. They had a stronger hull, carried more fuel and their armament was revised. The submarines had a length of 217 feet (66.1 m) overall, a beam of 23 feet 9 inches (7.2 m) and a draft of 14 feet 1 inch (4.3 m). They displaced 814 long tons (827 t) on the surface and 990 long tons (1,010 t) submerged. The S-class submarines had a crew of 48 officers and ratings. They had a diving depth of 350 feet (106.7 m).
For surface running, the boats were powered by two 950-brake-horsepower (708 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650-horsepower (485 kW) electric motor. They could reach 14.75 knots (27.32 km/h; 16.97 mph) on the surface and 9 knots (17 km/h; 10 mph) underwater. On the surface, the third batch boats had a range of 7,500 nautical miles (13,900 km; 8,600 mi) at 10 knots (19 km/h; 12 mph) and 120 nmi (220 km; 140 mi) at 3 knots (5.6 km/h; 3.5 mph) submerged.
Spearhead was armed with six 21 inch (533 mm) torpedo tubes in the bow. She carried six reload torpedoes for a grand total of a dozen torpedoes. Twelve mines could be carried in lieu of the torpedoes. The boat was also equipped with a 4-inch (102 mm) deck gun.
Construction and career
HMS Spearhead was laid down at Cammell Laird's Birkenhead shipyard on 18 August 1943, was launched on 2 October 1944 and completed on 21 December 1944. So far she has been the only ship of the Royal Navy to bear the name Spearhead. Spearhead survived the Second World War and was sold to the Portuguese in August 1948 and renamed NRP Neptuno.
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