CCGS Sir Humphrey Gilbert[a] is a former Canadian Coast Guard light icebreaker and buoy tender that was later sold to a private owner and renamed Polar Prince.

The vessel can carry 467.00 m3 (102,730 imp gal) of diesel fuel and had a range of 10,000 nautical miles (19,000 km) at 12 knots (22 km/h) and could stay at sea for up to 30 days.

The ship was launched on 29 October 1958 and named after Humphrey Gilbert, an early explorer of the Northwest Passage.

Sir Humphrey Gilbert had already been detailed to aid a fishing vessel in the Atlantic, but was redirected to Douala as the French ship was in danger of foundering.

The Coast Guard vessel was delayed in arriving on the scene by the barge and on 21 December, Douala sank.

[9] In 1983, Sir Humphrey Gilbert became the test vessel for the Coast Guard's lay day crewing system.

[10] Sir Humphrey Gilbert received a mid-life refit at the Halifax Shipyard in 1984 which significantly changed the ship.

Her original bow was cut off and replaced with a new one with an air bubbler system to reduce friction when breaking ice.

The ship departed on 1 July from Toronto, Ontario, and sailed down the Saint Lawrence Seaway and St. Lawrence River to Halifax, Nova Scotia, via the Northumberland Strait and the Canso Canal, then travelled north around Newfoundland, the Labrador coast, around Baffin Island and through the Northwest Passage, then around Alaska and down the Pacific coast through the Inside Passage, to Victoria, British Columbia.

[22] Polar Prince was released from the investigation and returned to its owners later in 2023, resuming training operations based out of Stephenville, Newfoundland by January 2024.