Other escapees relied more on physical strength and endurance. An escapee on August 26, 1987 used meat hooks to scale the fences,[136] while in 1971 a doctor swam 45 kilometres (28 mi) across the Baltic Sea from Rostock almost to the Danish island of Lolland, before he was picked up by a West German yacht.[137] Another escapee used an air mattress to escape across the Baltic on September 2, 1987.[138]