Directly ahead on the extension of the ship's fore and aft line. … [Read more...]
Davits
A set of arms on a ship from which its lifeboats are suspended. … [Read more...]
Datum marker buoy
Droppable floating beacon used to determine actual sea current or to serve as a location reference in SAR Operations. … [Read more...]
Datum
A geographic point, line, or area used as a reference in search planning.(1) The most probable position of a search target at a given time. (2) The plane of reference to which all data as to the depth on charts are referenced … [Read more...]
Dirty Ballast
A term applied to the seawater used for ballast when it is contaminated with the remnants or residue left in cargo tanks that previously carried crude oil or heavy persistent refined oils. … [Read more...]
DSC
DSC or Digital Selective CallingA technique using digital codes which enable a radio station to establish contact with, and transfer information to, another station or group of stations. DSC is available in VHF, MF and HF bands. … [Read more...]
Dynamic Positioning
DP or Dynamic PositioningThe ability of a ship to maintain automatically a pre-set position and heading using its own propellers and thrusters. … [Read more...]
DGNSS
Differential Global Navigation Satellite System: an augmented GNSS, including DGPS, which provides increased accuracy and integrity. … [Read more...]
Deep Sea Pilot
A pilot engaged in sea areas where there are specific dangers, high traffic density or other navigational hazards. … [Read more...]
Dangerous area
An area on a tanker which for the purposes of the installation and use of electrical equipment is regarded as dangerous. … [Read more...]