The seaman's name for any floating navigational mark, such as a buoy or lightship, as opposed to a landmark. Because sea-marks are moored to the seabed and can drag their mooring, navigators tend to treat their position with some caution when using them to fix their ship's position. Centuries ago, marks set up ashore in Britain were known as sea-marks, not landmarks, and in its original charter Trinity House was empowered to place sea-marks ashore whenever necessary as an aid to navigation. Any person found destroying them was fined or, if unable to pay, outlawed.
Subjects: Maritime History — Warfare and Defence.