Douglas Urry, a Canadian serving in the Royal Navy, took this rare photograph of a sinking merchant ship, the SS Audax, torpedoed on 6 September 1918.

It depicts the essence of the U-Boat campaign. If U-Boats could sink enough merchant ships carrying war supplies, munitions, and service personnel, they could starve the island nation of Great Britain into submission. The U-Boats almost succeeded. Unrestricted submarine warfare sank hundreds of merchant ships from early 1917, but the introduction of the convoy system, with warships protecting large groups of merchant ships, greatly reduced such losses.

George Metcalf Archival Collection
CWM 20030213-002_42a