Aspect Ratio - The ratio of the height of a sail to its width. A high aspect ratio sail is relatively tall and narrow - more typical on catamarans.

Abeam - Along the line at or near 90 degrees to the fore & aft axis of the vessel. Alternatively along an approximate line of either 3 or 9 o'clock to the helmsman standing in a conventional position. The term is only relevant to crew on the vessel at a moment in time. It should NOT be used for a description of position between two agencies. See further item on Position Reporting in the Navigation section.

Broaching - As the boat moves down the face of a wave the bow can bury in the trough and the stern can be pushed so far that boat becomes beam on to the wave.  The boat is now broached and can then be rolled or swamped by the wave.

Chine - The angle between a vessel's topside and bottom.

EPIRB - Emergency Position Indicating Radio Beacon.                                                      Library Catalogue

Gunwhale (Gunn'l) - The upper edge of the topside of a vessel.

Heel - The angle at which a boat lies as a result of the wind - especially sailing craft.  (See also List and Loll)

Heaving-To - Methods used to stop or slow down the vessel in heavy weather.

Knot - A measure of the mariner's speed over the surface of the earth in Nautical Miles per Hour.  One Nautical Mile is defined as the distance subtended on the earth's surface by one minute of latitude. (Approximately 6080 ft.or 1.85 Km)

Lee Shore - The shore in the lee of the vessel.

List - The angle at which a boat lies as a result of off-centre weight - especially crew. (See also Loll & Heel)

Loll - The natural angle at which a boat lies without interference from external forces such as wind & crew. (See also List and Heel)

Occulting - Steady light with regular periods of total eclipse where the period of light is greater than that of darkness.

Pitching - The up & down motion of the bow as the water arrives and leaves.

Pitchpole - An overtaking wave forces the vessel's bow under and lifts the stern so high that the vessel is turned end over end.

Scope - The ratio of the length of anchor line to the depth of the water.                                 Library Catalogue

Spring Line - A mooring line tied to prevent or minimise forward and aft movement of the vessel.

St Elmo's Fire  -  the electric brush-like discharge which takes place at mastheads and yardarms of a ship during certain atmospheric conditions. Some considered it as a good omen, foretelling an end to bad weather. Others believed that if the light from the ‘fire’ fell upon a sailor’s face, he would die within the next 24 hours.

Wash - The disturbance in the water caused by the passage of a vessel - which causes damage, injury or annoyance to others. The magnitude depends primarily on the type of hull, the speed of the vessel, the depth of water and the prevailing natural water state.

Yawing - The involuntary swinging from side to side of the intended course.