From Zelda Legends Wiki
Located at A1, a dungeon Link visits in order to rescue Aryll. He gets hurt by the boss, Helmaroc King, and has to return again later. The dungeon is the former hideout of a group of pirates, and is made up of and surrounded by many broken pieces of ships. Ganondorf took over this fortress when he escaped from Hyrule to the surface world. Contains the Skull Hammer and a portal to Ganon's Castle.