HMCS Otter was an armed yacht in service with the Royal Canadian Navy during World War II.

Conseco was acquired and brought north to Halifax, Nova Scotia where the vessel was converted to an armed yacht in 1940.

Renamed Otter the ship participated in the Battle of the Atlantic, escorting convoys and patrolling the Canadian coast.

[2] Constructed for Vincent Astor by Robert Jacob Shipyard of City Island, New York as Nourmahal, the vessel was launched in 1921.

[3][1] To augment the local sea defences of East Coast ports in World War II, the Royal Canadian Navy sought large, steel-hulled yachts to requisition.

Canada turned to its southern neighbour for suitable ships, finding several that met the navy's requirements.

[5] Philip S. Ross, a business executive from Montreal, Quebec was sent to acquire Conseco after his own yacht had been requisitioned.

[1] Conversion to an armed yacht involved removing most of the luxurious finery and installing naval hardware.

[1][8] The ship was assigned to the Halifax Local Defence Force, alternating between training duties and anti-submarine patrols.

Then, on 26 March 1941, the ship was ordered to await the arrival of the submarine HMS Talisman off the Sambro Light Vessel.