Lieutenant Commander William Sanders RNR, from Takapuna, was commissioned in the Royal Naval Reserve and given command of Q 21, HMS PRIZE. In April 1917 HMS PRIZE encountered the German Submarine U 93 and fought what is described as the classic Q Ship action. For sinking the U-boat Sanders was awarded the Victoria Cross and promoted to Lieutenant Commander.
Six weeks later, having made good the damage sustained during the action, Sanders and his men fought an action very similar to their first, in which HMS PRIZE was badly damaged and Sanders wounded. Although the action was unsuccessful, Sanders was awarded the Distinguished Service Order.
Two months later HMS PRIZE had again been repaired and was at sea in search of submarines. On 13 August 1917, a submarine was sighted but it submerged without attacking. That night HMS PRIZE was hit by a torpedo and lost with all hands.