During the Second World War, designated convoy rescue ships accompanied some Atlantic convoys to rescue survivors from ships that had been attacked. Rescue ships were typically small freighters with passenger accommodation converted to rescue service. This involved enlarging galley and food storage areas and providing berthing and sanitary facilities for approximately 150 men. Preparation for service included the installation of scrambling nets along the sides, and the substitution of boats suitable for open sea work for normal lifeboats. Rescue ships normally included a small operating room for an embarked naval doctor and sick bay staff. Service The first specially equipped rescue ship went into service in January 1941. When rescue ships were unavailable, large, ocean-going tugboats or converted trawlers were sometimes designated to perform rescue duty. By the end of the war 30 rescue ships had been built or converted. They participated in 797 convoys and rescued 4,194 survivors from 119 ships. Seven rescue ships were lost, six to enemy action (three to U-boats and three to aircraft). Origins In 1940 Admiral Sir Max Horton (later Commander-in-Chief Western Approaches Command) broached the idea of rescue ships with the Admiralty. The concept was to have merchant vessels that would accompany convoys but not carry cargo; they would instead have the role of saving the lives of seamen from ships sunk by enemy action. The rescue ship would take its position at the rear of one of the central columns of ships. From this position it could observe damaged ships falling astern of the convoy and quickly rendezvous to transfer survivors. The rescue ships would also be able to provide surgical or other treatment as required. This would free the cargo vessels of the convoy to continue on their way and escorts to focus on countering the attacking U-boats or aircraft. The convoy rescue ship was a response to early experience. Each merchant ship in a convoy was assigned a station so that the convoy formation would consist of several columns of three to five ships. The lead ships of the columns were spaced at intervals of 1,000 yards (910 m) along a line perpendicular to the convoy course. Each ship in the column followed the ship ahead at a distance of . The typical convoy would be approximately wide and long. The rescue plan for early convoys was to have the last ship of each column rescue survivors of other ships