submarine, pigboat, sub, U-boat
['wool, woolen, woollen', 'upright, upright piano', 'sea cucumber, holothurian', 'trimaran', 'great white shark, white shark, man-eater, man-eating shark, Carcharodon carcharias', 'killer whale, killer, orca, grampus, sea wolf, Orcinus orca', 'electric ray, crampfish, numbfish, torpedo']