Glossary


  • AIS

    The automatic identification system (AIS) is an automatic tracking system used for collision avoidance on ships and by vessel traffic services (VTS).
  • Bilge

    The bilge is the lowest compartment on a ship, below the waterline, where the two sides meet at the keel.
  • Bilge pump

    A bilge pump is a water pump used to remove bilge water. Since fuel can often be present in the bilge, electric bilge pumps are designed to not cause sparks and are typically fitted with a float switch, which turn on the pump when the water in the bilge rises above a pre-set level.
  • check valve

    A check valve, or a one-way valve is a valve that normally allows fluid to flow through it in only one direction.
  • cockpit

    The cockpit on a sailboat, is traditionally an open well in the deck of the boat which, among other things, contains the primary controls.  Typically located towards the stern of the boat, the cockpit is considered the safest external location for crew.
  • companionway

    The companionway is a raised hatchway in a ship's deck, with a ladder leading below and may be secured by doors or, more commonly on sailboats, hatch boards which fit in grooves in the companionway frame. The boards, typically 3 individual boards of graduated witdh,  allows for the lowest board to be left in place during inclement weather to minimize the amount of water getting below while still providing good ventilation.
  • DSC

    Digital Selective Calling DSC allows the radio to transfer information digitally, not just by voice, and to instantly send a digital distress alert to the Coast Guard. Part of that alert is a nine-digit Maritime Mobile Service Identity (MMSI) number that identifies your boat.
  • foredeck

    The part of a ship's deck that lies forward of the mast.
  • halyard

    A halyard is a line (rope) used for raising and lowering a sail, spar or flag on a sailing vessel.
  • keel

    The keel is the key structural element on a sailboat and can range from a "full keel" running the entire length of the boat to a "fin keel" - in essence, a flat blade sticking down into the water from a sailboat's bottom.   In all cases, it serves two functions: it provides lateral resistance, preventing the boat from being blown sideways by the wind, and it provides the ballast that keeps the boat right-side up.
  • lifeline

    Lifelines are any of various lines running above the decks, spars, etc., of a ship or boat to give sailors something to grasp when there is danger of falling or being washed away.
  • Mal-de-mar

    nausea and dizziness, sometimes accompanied by vomiting, resulting from the rocking or swaying motion of a vessel in which one is traveling at sea.
  • MMSI

    Maritime Mobile Service Identity The nine-digit MMSI number is a bit like a phone number for your boat and is used by maritime Digital Selective Calling (DSC), Automatic Identification Systems (AIS) and certain other equipment to uniquely identify a ship or a coast radio station. All DSC capable equipment (including AIS units) associated with the specific vessel should use the same MMSI number, since the MMSI serves to identify the vessel, not the equipment.
  • running rigging

    The running rigging is the rigging of a sailing vessel that is used for raising, lowering, shaping and controlling the sails.
  • shroud

    Shrouds are pieces of standing rigging which hold the mast up from side to side on a sailboat.
  • tender

    A ship's tender, is a boat, used to service or support it by transporting people and/or supplies to and from shore or another ship.  Smaller tenders are typically refered to as dinghies and are typically carried or towed by the "mother ship"