On May 24 1917, as a response to the unrestricted targeting of Allied merchant ships by German U-boats, the convoy system was introduced. All merchant ships crossing the Atlantic Ocean were to travel in convoys, under the protection of the British Navy. The US’s entry to the war on 6 April 1917 heightened the need for convoy protection, as US soldiers were being transported across the Atlantic to Europe. A convoy consisted of between 10–50 merchant ships and possibly a ship carrying ammunition and soldiers. It would be escorted by a cruiser, destroyers, armed trawlers and torpedo boats with equipment that detected submarine activity underwater. A fast warship acted as a scout, leading the convoy. At its rear was a ‘lookout’ ship and sometimes there would be a ‘straggler’, an armed merchant ship. The convoys reduced the number of ships destroyed by U-boats and deterred U-boat attacks.
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