He retired from the RN in 1934 as a Lieutenant Commander when cutbacks during the Great Depression ended his possibility of promotion.

[1] He returned to British Columbia after his retirement from the Royal Navy and had been ranching for a living when the Second World War broke out in 1939.

After an initial period ashore in Sydney, Nova Scotia Prentice was appointed Senior Officer, Canadian Corvettes under Commodore Leonard W. Murray.

It was in this latter capacity that Prentice scored Canada's first U-boat kill, shared with HMCS Moose Jaw.

[2] After his time in corvettes, Prentice was assigned to develop training and doctrine for the new Canadian destroyers that entered into service in 1942.