Egypt Maritime COC Deck key terms

The shortest track between two points on the Earth's surface, formed by the intersection of a plane through the Earth's centre with the surface; plotted as a curve on a Mercator chart.

A track crossing every meridian at the same angle, appearing as a straight line on a Mercator chart; longer than the great circle but simpler to steer and plot.

A cylindrical chart projection on which meridians are parallel straight lines and latitude scale expands with latitude, preserving shape and bearing but distorting distance and area at high latitudes.

A radar navigation technique in which a line drawn parallel to a chosen charted feature is kept at a fixed distance on the radar display to confirm the vessel remains on her planned track.

The vertical distance between the lowest point of the hull and the seabed, allowing for squat, tide, swell and charted depth accuracy; a critical limit in confined or shallow water passage planning.

The reduction in under-keel clearance and change of trim experienced by a vessel moving through shallow water, increasing with speed and block coefficient and greatest in water of limited depth.

A celestial position-fixing technique in which a calculated altitude is compared with the observed altitude to plot an intercept along the azimuth of the body from the assumed position.

A conveniently chosen latitude and longitude, near the dead reckoning position, used for sight reduction so that tabulated values can be entered simply and the resulting intercept plotted.

The altitude of a celestial body above the rational horizon computed for the assumed position at the time of observation, compared with the sextant altitude to obtain the intercept.

The angle measured with a marine sextant between a celestial body and the visible horizon, which must be corrected for index error, dip, refraction and semi-diameter before use.

The residual error of a sextant when the horizon and its reflected image do not coincide at zero reading on the arc; it is measured and applied as a correction to every sight.

The allowance subtracted from a sextant altitude because the visible horizon lies below the true horizon when the observer's eye is above sea level; it increases with height of eye.

The estimated position obtained by advancing a known position through courses steered and speeds or distances run, without reference to external position fixes.

The best position derived from dead reckoning refined by additional information such as a single line of position, tidal set and drift, or a depth contour.

A position determined by measuring the ranges and bearings of at least two identified charted objects on the radar display and plotting them on the chart.

A situation in which another vessel's compass bearing remains steady while her range falls, indicating risk of collision and requiring early, substantial action under the steering and sailing rules.

The condition deemed to exist when two vessels approach on converging courses and a steady bearing develops or the range decreases; it must be assessed early using all available means.

The vessel required by the steering and sailing rules to take early and substantial action to keep well clear of the stand-on vessel, altering course and speed as appropriate.

The vessel that initially keeps her course and speed when another vessel is required to keep clear, but must take action once collision cannot be avoided by the give-way vessel alone.

A navigable stretch of water, often marked by buoys or charted limits, in which vessels must keep to the starboard side of the fairway and avoid crossing unnecessarily.

A routing measure, adopted by IMO, that divides opposing traffic streams by traffic lanes, separation zones or lines to reduce head-on encounters in congested waters.

The apparent loss of stability caused by liquid in a partly filled tank shifting transversely as the ship heels, raising the centre of gravity and reducing metacentric height.

The distance between the centre of gravity and the transverse metacentre; a measure of initial transverse stability, positive when the metacentre lies above the centre of gravity.

The horizontal distance between the centre of buoyancy and the centre of gravity acting through a heeled vessel, producing the moment that returns the ship upright.

The ratio of the underwater volume of the hull to the volume of a rectangular block of the same length, breadth and draught; a measure of hull fullness affecting resistance and squat.

The reduction applied to metacentric height to account for the free surface moment of liquids in partly filled tanks, calculated from tank dimensions and liquid density.

The stable angle of heel adopted by a vessel with negative metacentric height, where the righting lever is zero but the ship is not in stable equilibrium.

Material such as timber, mats or airbags placed between or beneath cargo to spread weight, allow ventilation, prevent movement and keep the cargo clear of the deck or tank top.

The system of lashings, chains, turnbuckles and stoppers used to restrain cargo against ship motion, planned according to a cargo securing manual and anticipated accelerations.

A drawing or list showing where each consignment is placed in the ship, by bay, hold or tank, with weights and port of discharge, used for stability and discharge planning.

The division of the hull into compartments by watertight bulkheads and decks that limit flooding and preserve buoyancy and stability after damage.

A vertical partition separating compartments of the hull; collision and watertight bulkheads are designed to withstand water pressure and confine flooding to the damaged space.

The ability of a vessel to remain afloat and upright after one or more compartments are flooded, assessed against subdivision and survivability criteria in the applicable stability regulations.

The apparent deflection of moving air or water caused by the Earth's rotation, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

The theoretical wind that blows parallel to straight isobars when the pressure gradient force is balanced by the Coriolis force, above the friction layer.

A rule stating that in the Northern Hemisphere, with your back to the wind, low pressure lies to your left; reversed in the Southern Hemisphere, it helps locate pressure centres.

An intense low-pressure system over warm tropical seas with organised convection and maximum winds near the centre; it is called a hurricane, typhoon or cyclone by region.

The half of a tropical cyclone, in the Northern Hemisphere the left-hand side, where winds and seas are less violent and the vessel can run with the wind on her quarter.

The internationally agreed system of terrestrial and satellite radio communications, including digital selective calling and distress alerting, that provides distress, urgency and safety communications at sea.

A radiotelephone technique using coded digital signals on VHF, MF and HF to initiate distress, urgency and routine alerts and to establish communication with specific stations.

A narrow-band direct-printing service broadcasting maritime safety information such as navigational and weather warnings to ships within range of coastal transmitters.

The spoken distress signal used on radiotelephony to announce that a vessel or person is in grave and imminent danger and requires immediate assistance.

A transmission, by digital selective calling, Inmarsat or other approved means, that signals grave and imminent danger and includes the vessel's identity and position where possible.

A maritime safety message issued when winds of force ten or above are expected, broadcast to shipping to allow masters to take avoiding or preparatory action.

A certificate issued by the flag administration stating the minimum number and qualifications of seafarers required to operate the vessel safely, which the master must ensure is met.

The smallest number of qualified personnel the administration considers necessary for the safe operation of a ship, taking account of trading area, automation and emergency duties.

The continuous system of bridge, engine-room and cargo watches maintained by qualified officers and ratings, with proper handover, to ensure the safe operation of the vessel at all times.

A dedicated person stationed to maintain a proper visual and auditory watch and to report sightings, so that the officer of the watch can assess risk and take action.

The International Convention for the Prevention of Pollution from Ships, which regulates discharges of oil, noxious liquids, sewage and garbage and sets requirements for pollution-prevention equipment.

A statutory record in which all oil transfers, discharges, machinery-space bilge operations and tank cleanings are entered and signed for inspection by port state control officers.

A required shipboard plan setting out procedures for collecting, processing, storing and discharging garbage in accordance with MARPOL Annex V and the ship's garbage record book.

The documented structure of procedures, responsibilities and checks required by the ISM Code to ensure safe ship operation and pollution prevention, verified by audits and certificates.

A posted schedule assigning every person on board specific emergency duties and a muster station, including substitutes for key personnel, in the event of fire, abandon ship or other emergency.

The order to leave the vessel when it can no longer be kept afloat or safely fought, executed by mustering, accounting for all persons and launching survival craft as drilled.

A set of pre-planned procedures and checklists for foreseeable emergencies such as fire, collision, grounding, flooding and pollution, exercised through regular drills.

The person, usually the master of the first vessel to arrive at a distress scene, designated to coordinate search and rescue efforts of other craft until a rescue coordination centre takes over.

The official at a rescue coordination centre responsible for directing the conduct of a search and rescue operation within a designated search and rescue region.

The most probable position of a person or object in distress, taking account of drift, from which search patterns and the search area are calculated.

A planned track, such as expanding square, sector or parallel sweep, followed by searching craft to cover a search area systematically with the required probability of detection.