Glossary: G

13 terms.

• Gangway
  A portable access ladder or bridge rigged over the ship's side to allow persons to embark and disembark safely.
• Garbage Record Book
  A mandatory log recording all garbage disposal and incineration operations on board, required under MARPOL Annex V.
• General Cargo Ship
  A multipurpose vessel with cargo holds, tween decks, and derricks or cranes, designed to carry a variety of break-bulk and unitised cargoes.
• Generator Set
  A diesel-electric power unit installed in a ship's hold or on deck to supply electrical power to reefer containers.
• Global Maritime Distress and Safety System
  An internationally agreed set of safety procedures and communications equipment required on SOLAS ships for distress and safety.
• Global Positioning System
  US satellite-based radionavigation system providing position, velocity, and time data worldwide to marine and other users.
• GMDSS Sea Area A1
  An area within range of at least one VHF DSC coast station providing continuous alerting coverage, typically within 20–50 miles of shore.
• GMDSS Sea Area A2
  An area beyond A1 but within MF DSC continuous coverage, typically up to 400 nautical miles from shore.
• GMDSS Sea Area A3
  An area beyond A1 and A2 within coverage of an Inmarsat geostationary satellite, covering most ocean areas between latitudes 70°N and 70°S.
• GMDSS Sea Area A4
  The polar sea areas beyond GMDSS Area A3, not covered by geostationary satellites, where HF radio is used for distress alerting.
• Graving Dock
  A watertight basin into which a vessel is floated, then dewatered, allowing access to the entire underwater hull for inspection and repair.
• Great Circle
  The shortest route between two points on a sphere, formed by the intersection of the sphere and a plane through its center.
• Gyrocompass
  A compass using a gyroscope to find geographic north, unaffected by magnetic fields; mandatory on most large vessels.