shipwrecks_chance (Chance to spawn a shipwreck in a mapblock, in percent) int 15 0 100
shipwrecks_horizontal_displacement (Random horizontal displacement of the shipwreck from the center of mapblock) int 16 0 16
shipwrecks_vertical_displacement (Random negative vertical displacement of the shipwreck in sand) int 5 0 10
shipwrecks_seed (Seed for shipwreck generation) int 0