horizon m/s describes the sail of an preposition
gaff_topsail is fore_and_aft_sail. lateen is fore_and_aft_sail. fore_and_aft_sail is sail. balloon_sail is sail. headsail is sail. lugsail is fore_and_aft_sail. press_of_sail is sail. head_sail is sail. topsail is sail. sail is structure.