Rainbow class submersibles (1930)

The Rainbow-class submarine (R class) were four patrol submarines built for the Royal Navy in the early 1930s. Although six were envisioned at first, only four were completed due to budgetary reason. The class comprised the HMS Rainbow, Regulus, Rover, and Regent. They were in straight line derived from the Parthian or P class, and like them destined for the far east. Only one made her career there, and survived. The four were repatriated in Alexandria, served in the Mediterranean, and two were sunk by mines, one by collision. HMS Rover survived a bombing in Crete and was being repaired at Ceylon when the Japanese attack commenced in early 1942. She became a Training Submarine in 1945.

HMS Regent, seen from a plane in the Mediterranean, 1941

Design of the class

The Rainbow-class submarines were designed as improved Parthian class, also for long-range operations in the Far East, but yet smaller and more economical than the larger Odin and even the Parthian. They measured 287 feet 2 inches overall, for 29 feet 10 inches in beam and had a mean draft of 13 feet 10 inches (4.2 m). Displacing 1,772 long tons (1,800 t) surfaced and 2,030 long tons (2,060 t) submerged they carried a staff of 56 crewmen, and were capable of diving down to 300 feet (91.4 m).

Powerplant: It comprised for surface-running two 2,200 bhp (1,641 kW) diesels, connected to a propeller shaft each. Submerged power came from two 660-horsepower (492 kW) electric motor enabling a durfaced top speed of 17.5 knots (32.4 km/h; 20.1 mph) and 9 knots (17 km/h; 10 mph) underwater. Their range, always surfaced, reached 7,050 nautical miles (13,060 km; 8,110 mi) at the cruise speed of 9.2 knots (17.0 km/h; 10.6 mph) but down to just 62 nmi (115 km; 71 mi) undderwater at 4 knots (7.4 km/h; 4.6 mph).

Armament: The four boats had the same six 21-inch torpedo tubes in the bow, two more in the stern. They just carried a reload for eaxch of the bow tubes, so a grand total of fourteen torpedoes in all. They also carried the same QF 4.7-inch (120 mm) Mark IX “deck” gun. Like on previous class the gun was carried in a structure and well protected, typical of this generation of British submersibles.

HMS Rover surfacing close to a British AMC in the Mediterranean

HMS Rainbow, stern

The Rainbow class in action

HMS Rainbow served in the Far East until 1940, and then moved to the Mediterranean to face te Regia Marina. She was on patrol off Calabria on 23 September 1940 but disappeared as reported later, believed to have been sunk on 4 October in a collision with the Italian merchant ship Antonietta Costa reporting a massive underwater explosion after a schock, while underway in convoy from Albania. And until 1988 some historians advanced she had been sunk by the Italian submarine Enrico Toti, but this proven to be HMS Triad so the collision is the theory that remains.

HMS Regulus was built at Vickers-Armstrong at Barrow-in-Furness, stationed with the fourth Submarine Flotilla on the China station out of Hong Kong. In October 1939 she started a dangerous intel mission in the mouth of the Bungo Strait, off the coast of Japan, and observed IJN fleet exercises including several aircraft carriers. She even later entered Shibushi Bay and Osaka Bay to take photos. Back in the Mediterranean like the rest of the class, she made a patrol under command of Lt.Cdr. Frederick Basil Currie, from Alexandria to the southern Adriatic on 23 November 1940 but presumed los on 6 December 1940 off Taranto, probably hitting a mine.

HMS Rover was commissioned on 29 January 1931, assigned like her sisters to the 4th Submarine Flotilla, China Station. In 1939 she was repatriate to Alexandria and patrolled the Suez canal, after being transferred via Singapore in early 1940. She teamed with the RAN in the Mediterranean, from Aden (August) and in early 1941 attacked Italian convoys.
In April 1941 during the Battle of Crete she was in Souda Bay helpint the crew of HMS York. On 24 April she was attacked by Stukas and bandly damaged. She was saved, but had to be towed to Alexandria and then Singapore for full repairs. She stayed there, to stem the Japanese advance in ealry 1942, operating from Bombay. She operated off Trincomalee, Ceylon and allegedly sunk ten Japanese ships during her numerous patrols. In 1945 she was a TS. She was sold for BU and scrapped on 30 July 1946.

Like the others, HMS Regent was based in the China Station, 4th flotilla, and in April-May 1940 transferred to the 1st Submarine Flotilla in Alexandria, Egypt. From there she started a long wartime patrol career against axis convoys. She sank or damaged four ships during her career: On 5 October 1940 the 188 GRT Maria Grazia, and on 9 October the 5,900 GRT Antonietta Costa (so badly damaged she was a Total Loss), then on she sank on 15 January 1942 the 2,742 GRT Città di Messina and on 21 February 1942 the German-held Menes (5,609 GRT), badly damaged and written off.
He loss was a bit of a mystery. The most likely theory is that she was attacking a railways on 16 April 1943 in the Gulf of Taranto, engaged by the Italian corvette Gabbiano. She survived and two days later attacked a convoy off Monopoli but missed. An explosion was heard and now it is believed she hit a mine.

Read More

Books

Conway’s All the World’s Fighting Ships 1921-47
Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing
Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press.
Caruana, Joseph (2012). “Emergency Victualling of Malta During WWII”. Warship International.
Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). Chatham Publishing.
McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. Vol. 129. Oxford, UK: Osprey.

Links

https://uboat.net/allies/warships/class.html?ID=47
https://www.battleships-cruisers.co.uk/rainbow_class.htm