KMA Cadet 1st-Stage Exam key terms

A method of estimating a vessel's present position by advancing a known starting point using course steered, speed through the water, and elapsed time, without reference to external position fixes.

The best-available position obtained by correcting a dead-reckoning position for the estimated effects of current, wind-driven drift, and leeway.

Set is the direction toward which a current flows; drift is its speed, usually expressed in knots. Together they describe the current's effect on a vessel's track.

The actual direction of travel of a vessel across the seabed, combining heading, current, and leeway; derived from successive position fixes rather than from the compass alone.

The direction in which a vessel's bow points at any instant, measured clockwise from north and read from the steering compass or gyro repeater.

The angular error in a magnetic compass caused by the vessel's own magnetic field and nearby ferrous metal or electrical equipment; it varies with heading and is recorded on a deviation card.

The angular difference between true north and magnetic north at a given place, caused by the Earth's magnetic field and shown on charts with its annual rate of change.

The reference level to which depths printed on a nautical chart are reduced, normally close to lowest astronomical tide so that actual depths are usually greater than charted.

The vertical distance between the lowest point of a vessel's hull and the seabed, calculated from charted depth, predicted tide, and the vessel's maximum draught, with an allowance for squat and swell.

The reduction in under-keel clearance and change of trim experienced by a vessel moving through shallow water, caused by increased water velocity and lower pressure beneath the hull.

A large slow-speed marine diesel engine in which combustion occurs once per crankshaft revolution, with a separate crosshead and piston rod, typically burning heavy fuel oil and directly coupled to the propeller.

A measure of a fuel's resistance to flow, used to determine the temperature to which heavy fuel oil must be heated for correct atomisation at the injectors, typically 10-15 cSt at injection.

The chapter of the MARPOL Convention regulating air pollution from ships, covering sulphur content of fuel, nitrogen oxide emissions from engines, ozone-depleting substances, and energy efficiency requirements.

A sea area designated under MARPOL Annex VI where stricter limits apply to sulphur oxides and particulate matter, and often nitrogen oxides, requiring low-sulphur fuel or an approved equivalent method.

An exhaust gas cleaning system that removes sulphur oxides from engine emissions by washing the gas with seawater or alkaline solution, allowing continued use of high-sulphur fuel inside emission control areas.

A MARPOL Annex VI measure expressing a ship's carbon dioxide emissions per tonne-mile of transport work, compared against a required reference value to rate its efficiency.

An annual operational rating from A to E assigned under MARPOL Annex VI that measures grams of carbon dioxide emitted per unit of transport work actually performed by a ship.

The treatment and control of water taken aboard for stability, carried out under the Ballast Water Management Convention to prevent transfer of harmful aquatic organisms between ports.

Non-native organisms introduced into a new marine environment, commonly through ships' ballast water or hull fouling, where they can outcompete local species and damage ecosystems and fisheries.

The accumulation of micro-organisms, plants, and animals on submerged surfaces such as a ship's hull, which increases drag and fuel consumption and can transport species between regions.

The apparent rise in a vessel's centre of gravity caused by liquid moving freely in a partly filled tank, reducing effective metacentric height and therefore transverse stability.

The vertical distance between a vessel's centre of gravity and its transverse metacentre; a positive value indicates stable equilibrium and its size indicates resistance to small angles of heel.

The horizontal distance between the centre of gravity and the centre of buoyancy at a given angle of heel, producing the moment that tends to return a stable vessel upright.

A stable angle of heel, either side of upright, adopted by a vessel with negative initial metacentric height, where the righting lever is zero but the vessel is not capsizing.

The vertical distance from the waterline to the upper edge of the deck line at side amidships, assigned by the load line rules and indicating reserve buoyancy.

The Plimsoll mark and associated seasonal lines painted on a ship's side showing the maximum permitted draught in different zones and seasons under the International Convention on Load Lines.

A watertight transverse bulkhead fitted forward of the cargo space and within a prescribed distance from the stem, intended to limit flooding if the bow is damaged.

The division of a hull into compartments by watertight bulkheads and decks so that flooding from damage is confined, preserving buoyancy and stability after an incident.

The ability of a vessel to remain afloat and upright after one or more compartments have been flooded, assessed against survival criteria for residual freeboard, heel, and righting energy.

An international convention governing bills of lading that sets minimum carrier obligations for seaworthiness and care of cargo, together with defences and limits of liability.

A document issued by a carrier acknowledging receipt of goods for shipment, evidencing the contract of carriage, and acting as a document of title that enables transfer of the goods.

A contract between a shipowner and a charterer for the hire or employment of a vessel, covering terms such as duration, hire or freight, laytime, and allocation of costs.

Laytime is the permitted time for loading or discharging without penalty; demurrage is the agreed compensation payable by the charterer for exceeding that allowed period.

A principle in maritime law under which extraordinary sacrifices or expenses deliberately incurred to save a ship and cargo from a common peril are shared proportionately by all parties with interests at risk.

Damage to or loss of a particular part of a ship or cargo from an insured peril, borne by the owner of the affected property or its insurer rather than shared among all parties.

A contractual provision extending the carrier's defences and limits of liability to servants, agents, and independent contractors such as stevedores who perform part of the carriage.

The International Convention for the Safety of Life at Sea, which sets minimum safety standards for construction, fire protection, life-saving appliances, navigation equipment, and operational procedures.

The International Safety Management Code, requiring shipping companies to establish a documented safety management system with defined responsibilities, procedures, and emergency preparedness both ashore and aboard.

Inspection of foreign-flagged ships in a port by the coastal authority to verify compliance with international conventions, with power to detain vessels having serious deficiencies.

The regulatory supervision exercised by the state whose flag a ship flies, covering survey, certification, and enforcement of international conventions on vessels on its register.

An independent technical organisation that sets and verifies standards for the design, construction, and maintenance of ships, issuing class certificates on which insurers and charterers rely.

A fixed expression from the IMO Standard Marine Communication Phrases used for routine and emergency ship-to-ship or ship-to-shore messages to remove ambiguity in multilingual operations.

A prescribed word such as 'question', 'instruction', 'advice', or 'warning' that signals the purpose of a Standard Marine Communication Phrases message so the receiver knows how to respond.

Twenty-foot equivalent unit, the standard measure of container capacity based on a box twenty feet long, used for vessel capacity, terminal throughput, and freight statistics.

A bay-by-bay diagram showing where each container is placed on a vessel, by slot, weight, and port of discharge, used to plan safe loading and efficient cargo operations.

The predicted vertical distance of the sea surface above chart datum at a given place and time, obtained from tide tables or harmonic predictions and used to calculate available water depth.

The power actually delivered to the propeller shaft after transmission losses, used to relate engine output to ship speed and fuel consumption in performance and efficiency calculations.