His handling of the RCN's war effort had its opponents however, and he was removed from his post as Chief of the Naval Staff in January 1944.

Brigadier General Nelles wrote to the Minister of Marine and Fisheries for an appointment for Percy in the future Canadian naval service.

[2] Due to the small size of the RCN, Canadian officers were sent to train on larger ships of the British Royal Navy to gain experience.

In early 1914, Nelles transferred to the cruiser HMS Suffolk, which was assigned to the North America and West Indies Station based at Bermuda.

With the breakout of the First World War, Suffolk was ordered to protect transatlantic shipping routes, then later patrolled between Bermuda and Halifax, Nova Scotia.

[2] In August 1925 Nelles returned to Canada and was promoted to commander and appointed senior naval officer, Esquimalt in December.

[2] On 18 March 1930 he was appointed executive officer aboard the recently refitted Danae-class cruiser HMS Dragon.

After consultation with the Admiralty, Nelles was appointed acting captain and continued Dragon's tour, being the first RCN officer to command a Royal Navy vessel.

[2] Due to favourable reports by his British commanders after the Dragon cruise and his seniority among Canadian officers, the Chief of the Naval Staff, Commodore Walter Hose recommended Nelles to be his successor.

[2][3] Nelles was made acting Chief of the Naval Staff in December 1933 and in July 1934 was confirmed in the position and was promoted to commodore.

[7] Rather than being publicly dismissed from duty, Nelles was transferred to Great Britain and given the nominal post of Senior Canadian Flag Officer Overseas (SCFO(O)), a largely administrative position with little involvement in naval operations.

[2] Royal Canadian Sea Cadets Corps 'ADMIRAL NELLES' was formed in 1940 to honour the Chief of the Naval Staff.