The Navy’s primary role during the two world wars was to protect and defend the Merchant Navy. This involved preventative measures including clearing underwater mines and forming maritime convoys.

The purpose of the convoys was to deter U‑boats (German submarines) and make it difficult for them to attack. Convoys were generally made up of 40 merchant ships escorted by naval vessels positioned in front and on either side.

Although it is difficult to get exact figures on the impact of the Navy in the First World War, during World War II it sank 31 U‑boats and lost only 14 of its own ships.