[7] From her arrival at Key West, Florida, from 5 December 1913 – 16 June 1914, Cassin sailed with the 6th Division in the Caribbean and Gulf of Mexico in fleet maneuvers and exercises.

She arrived at Queenstown, Ireland on 17 May, and began operations which called for her to rendezvous with American troop convoys at sea and escort them to ports in England and France.

On 15 October, she sighted the German submarine U-61 about 20 nmi (23 mi; 37 km) south of Mine Head Lighthouse, Monagoush, County Waterford, Ireland, and pursued her.

[7] According to the report issued by the Secretary of the Navy, the torpedo would have missed the Cassin entirely, except it breached the surface of the water on two occasions and turned to the left each time.

In fact, Fireman First Class F. W. Kruse is reported to have wandered out of his living compartment while completely unconscious after having had 84 in (2,100 mm) of frame blown away immediately adjacent to his bunk.

[12] One other casualty is attributed to the action, in that Dr. Dudley Walton Queen was seized with cerebrospinal meningitis caused by exposure to the elements, and died four days later on 19 October.

[7] Cassin's war service was honored on 12–13 December, when she was chosen as one of the escorts for George Washington, carrying President Woodrow Wilson into Brest, France, for his attendance at the Versailles Peace Conference.

[7] After winter maneuvers in the Caribbean, Cassin cleared New York City on 1 May for the Azores, where she took station guarding the route of the Navy's historic transatlantic NC-4 flight.

[6] Cassin was returned to naval custody on 30 June 1933; lost her name on 1 November 1933; struck off on 5 July 1934;[15] and sold for scrap on 22 August 1934.