HMS D1
HMS "D1" was one of eight D-class submarine built for the Royal Navy during the first decade of the 20th century. Description. The D-class submarines were designed as improved and enlarged versions of the preceding C class, with diesel engines replacing the dangerous petrol engines used earlier. The submarines had a length of overall, a beam of and a mean draught of . They displaced on the surface and submerged. The D-class submarines had a crew of 25 officers and ratings and were the first to adopt saddle tanks. For surface running, the boats were powered  by two diesels, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the D class had a range of at . The boats were armed with three 18-inch (45 cm) torpedo tubes, two in the bow and one in the stern. They carried one reload for each tube, a total of six torpedoes. Construction and career. "D1" was laid down by Vickers on 14 May 1907 and was launched on 16 May 1908 at Barrow. She was commissioned in September 1909. In 1910 , "D1" took part in the annual manoevures, during which she "torpedoed" two "Blue Fleet" cruisers off Colonsay. This showed that the D class could operate a considerable distance from their base at Fort Blockhouse. "D1" was sunk as a target on 23 October 1918 near Dartmouth. Wreck discovery. The wreck was discovered by divers looking for the remains of German U-Boats and has been afforded protected status.