A significant portion of the Second World War was fought and decided on the high seas. At the start of the conflict the Royal Navy was the largest in the world, though it suffered huge losses early on. The Battle of the Atlantic was the longest lasting continuous campaign of the entire war.
From 1941 the United States Navy saw significant growth and provided much needed support against German and Italian naval forces, as well as playing the central role in the Pacific war against Japan.
Here are 10 facts about British Naval engagement with the Germans in the Atlantic during World War Two.
1. Britain lost its first submarine to friendly fire on 10 September 1939, when HMS Oxley was mistakenly identified as a U-boat by HMS Triton. The first U-boat was sunk four days later.
2. German battleships flippantly seized an American transport ship on 3 October 1939, an early act that helped to turn public favour in the US against neutrality and towards helping the Allies.
3. 27 Royal Navy ships were sunk by U-boats in a single week in autumn 1940.
4. Britain had lost over 2,000,000 gross tons of merchant shipping before the end of 1940.
5. In September 1940 America gave Britain 50 destroyer ships in exchange for land rights for naval and air bases on British possessions. They were of First World War age and specification, however.
6. Otto Kretschmer was the most prolific U-boat commander, sinking 37 ships. He was captured by the Royal Navy in March 1941.
7. The establishment of the Pan-American Security Zone in the North and West Atlantic was announced by Roosevelt as part of the Lend-Lease Bill passed by Senate on 8 March 1941.
8. From March 1941 until the following February, codebreakers at Bletchley Park had great success in deciphering German Naval Enigma codes.
This made a significant impact in protecting shipping in the Atlantic.
9. The Bismarck, Germany’s famed warship, was decisively attacked on 27 May 1941 by Fairey Swordfish bombers from the HMS Ark Royal aircraft carrier.
The ship was scuttled and 2,200 died, whilst only 110 survived.
10. Germany renewed the Naval Enigma machine and codes in February 1942.
These were finally broken by December, but could not be read consistently until August 1943.