An island race needs a navy more than any other and, for the six long years of World War Two, Britain's lifeline was our senior service.
Here, British Pathe News brings to life the memories of the ordinary sailors who conquered both the sea and the enemy in the name of freedom, illustrated with some of the most amazing film ever taken from the deck of a ship.
The film recalls life on the ocean waves as it was experienced, with all its sweat, boredom, blood and terror.
Fight for the Sea is also available in the Britain at War eight-disc box set.