HMS Rainbow (N16)

HMS Rainbow was a Rainbow-class submarine submarine built for the Royal Navy during the 1930s.

Design and description
The Rainbow-class submarines were designed as improved versions of the Parthian class and were intended for long-range operations in the Far East. The submarines had a length of 287 ft overall, a beam of 29 ft and a mean draft of 13 ft. They displaced 1772 LT on the surface and 2030 LT submerged. The Rainbow-class submarines had a crew of 56 officers and ratings. They had a diving depth of 300 ft.

For surface running, the boats were powered by two 2200 bhp diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 660 hp electric motor. They could reach 17.5 kn on the surface and 9 kn underwater. On the surface, the boats had a range of 7050 nmi at 9.2 kn and 62 nmi at 4 kn submerged.

The boats were armed with six 21 in 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
Rainbow ran aground in the English Channel off Ventnor, Isle of Wight, on 22 January 1932. She was refloated later the same day.

Rainbow served in the Far East until 1940, when she moved to the Mediterranean. She left for a patrol off Calabria on 23 September 1940 and was due to be back in Alexandria on 16 October, she was last heard from on 25 September. She is believed to have been sunk on 4 October in a collision with the Italian merchant ship Antonietta Costa, which reported striking a submerged object at 03:30, followed by a huge underwater explosion while sailing in convoy from Albania on that date.

Until 1988 it was believed that Rainbow had been sunk by the ITALIAN SUBMARINE Enrico Toti, but eventually it was determined that HMS Triad (N53) was the submarine that Enrico Toti sank.