William Cavaye was born in Queensland, Australia, on 20 April 1906, the son of Frederick Napier Warden Cavaye and Emily Cavaye (née Hatfield). He moved to London as a 12-year-old schoolboy in July 1918 and joined the Royal Navy in June 1924.

After time as a Midshipman in HMS VALIANT and HMS RENOWN, he joined submarines as a Sub Lieutenant in April 1929 and, in August 1929, joined HMS L22.  This was followed by appointments to HMS M3 in November 1929 and, after promotion to Lieutenant, to HMS L19 in December 1930. Cavaye next travelled to Australia to join HMS OTWAY in April 1931, before the submarine transferred to the Mediterranean. In August 1931 he joined HMS H23 as First Lieutenant and, in September 1933, he was appointed to HMS OTUS, before, in December 1935, he attended the Commanding Officers’ Qualifying Course.

His first command appointment was to HMS SNAPPER in the Mediterranean in April 1936. After time in General Service and after the outbreak of WW2, in October 1939, he took command of HMS H43, followed by that of HMS URSULA in April 1940.  A short spell in Command of HMS TRIBUNE in Canada followed, after which, in June 1941, Cavaye took command of HMS TEMPEST, which deployed to the Mediterranean.

HMS TEMPEST was scuttled in the Gulf of Taranto on 13 February 1942, after a seven-hour depth-charge attack by the Italian Torpedo Boat CIRCE. Thirty-nine of the crew were lost. Cavaye died after being hit by shell fire after the submarine had surfaced.

He is commemorated on the Portsmouth Naval War Memorial on Panel No. 61 Column No. 3.