HMS Regulus (N88) was a built for the Royal Navy during the 1930s. Design and description The Rainbow-class submarines were designed as improved versions of the and were intended for long-range operations in the Far East. The submarines had a length of overall, a beam of and a mean draft of . They displaced on the surface and submerged. The Rainbow-class submarines had a crew of 56 officers and ratings. They had a diving depth of . For surface running, the boats were powered by two diesel engines, 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 boats had a range of at and at submerged. The boats were armed with six torpedo tubes in the bow and two more in the stern. They carried six reload torpedoes for a grand total of fourteen torpedoes. They were also armed with a QF 4.7-inch (120 mm) Mark IX deck gun. Construction and career Regulus was laid down by Vickers-Armstrong at Barrow-in-Furness and launched in 1930. Before Second World War she was stationed with Submarine Flotilla #4 on the China station, based out of Hong Kong. In October 1939 Regulus conducted intelligence-gathering operations in the mouth of the Bungo Strait, off the coast of Japan. It covertly observed Imperial Japanese Navy fleet exercises, including and a brand new Japanese aircraft carrier, likely . It had also entered Shibushi Bay and Osaka Bay via the Kitan Strait, producing photographic intelligence. Regulus (Lt.Cdr. Frederick Basil Currie, RN) left Alexandria to patrol in the southern Adriatic on 23 November 1940. She was lost with her entire crew on 6 December 1940 whilst on patrol off Taranto, Italy. In all probability she hit a mine. Notes References Rainbow-class submarines Ships built in Barrow-in-Furness 1930 ships World War II submarines of the United Kingdom Maritime incidents in December 1940 World War II shipwrecks in the Mediterranean Sea Ships lost with all hands