MARINA Second Engineer / Chief Engineer Theoretical Exam key terms

The average pressure that, if applied to the piston throughout the power stroke, would produce the measured shaft output; calculated from torque and engine geometry and used to compare loading between engines of different size.

The average cylinder pressure derived from an indicator diagram over a complete cycle, representing work delivered to the piston before mechanical and friction losses are subtracted.

A plot of cylinder pressure against volume or crank angle for one cycle, used to assess combustion quality, peak pressure, timing and the condition of fuel injection and exhaust valves.

Fuel mass burned per unit of shaft energy produced, usually grams per kilowatt-hour; a key performance indicator corrected to reference conditions for comparing engine efficiency and detecting deterioration.

The standard ambient air and cooling water temperatures, barometric pressure and humidity to which measured engine power and fuel consumption are corrected so results from different times and ships can be compared fairly.

Selection of a published engine rating below its maximum by reducing mean effective pressure, engine speed or both, to improve fuel economy, reduce thermal load and match the propeller curve at the contracted service speed.

The relationship between propeller power and speed in service, together with the power margin deliberately left between the engine layout point and the propeller curve to allow for fouling, weather and heavy running.

Cyclic twisting of the shafting caused by uneven torque from each firing stroke interacting with shaft stiffness and inertia; controlled by tuning, detuning or damping to keep stresses within allowable limits.

The crank angle at which fuel injection begins relative to top dead centre; too early raises peak pressure and knocking, too late raises exhaust temperature and reduces efficiency.

The component that opens at injection pressure and sprays fuel into the combustion chamber as a fine mist; worn nozzles cause poor atomisation, afterburning, high exhaust temperature and carbon deposits.

The supply of pressurised charge air from the turbocharger to the cylinders to clear burnt gases and provide oxygen for combustion; scavenge pressure and air cooler performance directly affect combustion and thermal load.

A heat exchanger that cools compressed scavenge air before it enters the cylinders, increasing air density and reducing thermal load; water-side fouling or air-side blockage raises exhaust temperatures.

The arrangement of sea water, low-temperature fresh water and high-temperature fresh water circuits that removes heat from engines and auxiliaries; a central cooler transfers heat from fresh water to sea water.

The circuit supplying filtered, cooled oil to bearings and cylinder liners, together with the detector that samples crankcase atmosphere and alarms on a rise in oil mist indicating overheating or bearing distress.

Monitoring of main and crankpin bearing temperatures and periodic measurement of the vertical distance the crankshaft has moved within its bearings, used to detect bearing wear before damage occurs.

A structured, shipboard and shore-based schedule of jobs with intervals, instructions, spare parts and records, used to plan maintenance, track defects and demonstrate compliance to surveyors and auditors.

Regular measurement of parameters such as vibration, temperature, oil analysis and performance so that developing faults are detected early and maintenance is scheduled on evidence rather than fixed intervals.

The formal process of recording an equipment defect or a failure to meet a required standard, assessing its risk, taking corrective action and closing the record with verification.

Operation with the engine room unattended for periods, monitored by alarms and a watch-call system that requires the duty engineer to acknowledge at set intervals and alerts others if not acknowledged.

The structured transfer of responsibility between duty engineers, covering plant status, ongoing jobs, defects, alarms, tank levels and standing orders, so the incoming watch is fully informed before taking over.

Written instructions from the chief engineer or master that apply continuously or during specified periods, supplementing the watchkeeper's professional judgement with specific requirements for rounds, reporting and action.

The system by which the officer of the watch orders propulsion settings from the bridge, transmitted to the engine control room and confirmed back, with the engineer observing limits and reporting any inability to comply.

Machinery whose failure would endanger the ship, persons or environment, together with the standby or duplicate arrangements provided so that a single failure does not leave the vessel without essential services.

An independently driven generator and its dedicated distribution board that supply essential services such as steering gear, emergency lighting, alarms and radio when the main power source fails.

A switching device that automatically interrupts fault current, selected and set so that the device nearest a fault trips first and healthy circuits remain supplied.

The resistance between an insulated conductor and earth, measured to confirm insulation health; an earth fault is an unintended connection to the hull that must be located and cleared.

A digital controller that executes programmed logic for machinery control, interlocking and alarm handling, collecting sensor inputs and driving outputs to actuators and the operator interface.

A control system designed so that a failure results in a safe condition, such as a shutdown or trip, rather than continued unsafe operation; its function is tested at defined intervals.

A certificate issued after survey confirming that a ship's oil pollution prevention arrangements, including the Oil Record Book and pollution prevention equipment, meet MARPOL Annex I requirements.

A statutory record of oil-related operations such as bunkering, transfer, discharge and disposal, kept in the prescribed format and available for inspection by authorities.

Equipment that separates oil from machinery space bilge water and monitors the effluent, automatically stopping overboard discharge when the oil content exceeds the permitted limit.

The ship's documented procedures for collecting, processing, storing and discharging garbage by category, supported by a record of each operation as required by MARPOL Annex V.

The regime for managing ballast water to prevent transfer of harmful aquatic organisms, including a ship-specific plan, a record book and treatment to the D-2 discharge standard.

A mandatory code requiring a safety management system with documented procedures, defined responsibilities, emergency preparedness and internal audits, verified by certificates held by the company and ship.

Inspection of foreign ships in port by the coastal authority to verify compliance with international conventions, with detention possible where deficiencies show the ship is not fit to proceed to sea.

The standards for certification, watch composition and minimum rest periods intended to prevent fatigue, recorded in hours of rest and subject to inspection.

An organisation that sets technical rules for hull, machinery and equipment and issues certificates after surveys confirming the ship remains in the condition required for its assigned class.

Placing the ship in a dock so the underwater hull, rudder, propeller and sea connections can be inspected, cleaned and repaired, usually combined with a periodic special survey and class requirements.

The condition of closures, bulkheads and fittings that keeps water out of or limits its spread within the hull, supported by plans, drills and damage control procedures for containing flooding.

The loss of effective stability caused by liquid moving freely in a partly filled tank, and the measure of initial stability given by the distance between centre of gravity and transverse metacentre.

The correct relative position of engine, intermediate shafting and propeller shaft so that bearing loads and bending moments remain within limits, checked by sag and gap measurements.