Crusader carried a maximum of 473 long tons (481 t) of fuel oil that gave her a range of 5,500 nautical miles (10,200 km; 6,300 mi) at 15 knots (28 km/h; 17 mph).

Following the Italian invasion of Abyssinia in August 1935, Crusader was sent with the rest of her flotilla to reinforce the Mediterranean Fleet the following month.

The ship began a major refit at Sheerness on 28 April 1938[6] to bring her up to Canadian specifications that included the installation of Type 124 ASDIC.

[10] Ottawa's stern was damaged in a collision with the tugboat Bansurf in April 1940, and repairs took two months to complete.

Ottawa assisted the British destroyer Harvester in sinking the Italian submarine Comandante Faà di Bruno on 7 November.

[12] Ottawa returned to Canada in June 1941 and was assigned to the RCN's Newfoundland Escort Force which covered convoys in the Mid-Atlantic.

[9] In early September, the ship's captain refused to allow her director-control tower and rangefinder to be removed in exchange for a Type 271 target indication radar.

On 14 September, while escorting Convoy ON 127 500 nautical miles (930 km) east of St. John's, Newfoundland, Ottawa was torpedoed by U-91.

She sank ten minutes later; 114 crewmen lost their lives, including the commanding officer, while nearby vessels rescued 69 survivors.