BD Marine Engineer Class 2 (Second Engineer) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Indicated power formula

Indicated power in kW equals mean indicated pressure in bar times stroke in metres times piston area in square metres times revolutions per minute times number of power strokes, divided by 60,000.

Brake thermal efficiency

The ratio of brake power output to the energy supplied by fuel, calculated as brake power divided by the product of fuel mass flow rate and lower calorific value, expressed as a percentage.

Specific fuel consumption

Fuel consumed per unit of brake power per hour, usually in grams per kilowatt-hour, obtained by dividing fuel flow in grams per hour by brake power in kilowatts.

Compression ratio

The ratio of the total cylinder volume when the piston is at bottom dead centre to the clearance volume at top dead centre, equal to swept plus clearance volume divided by clearance volume.

Crankcase oil mist alarm

A detector sensing oil mist from overheated bearings or pistons. On alarm, stop the engine, keep crankcase doors closed, allow settling and ventilation, then investigate before restarting.

Turbocharger surging

Unstable compressor flow occurring when the operating point crosses the surge line, often at low load or with a fouled compressor, producing pulsating airflow and abnormal noise.

Propeller law

For a fixed-pitch propeller in calm water, absorbed power varies with the cube of rotational speed and thrust with the square of speed, so small speed increases demand large power increases.

Engine layout diagram

A diagram defining the permissible operating envelope of a main engine, bounded by torque, mean effective pressure, maximum speed and overspeed limits, with the MCR and service points marked.

Crosshead engine lubrication

A two-stroke design with a stuffing box separating cylinder from crankcase, so cylinder oil is a separate total-loss system and crankcase oil lubricates only bearings and running gear.

Controllable-pitch propeller

A propeller whose blade angle can be changed to alter thrust at constant engine speed, allowing full engine load across the speed range and rapid manoeuvring without reversing the engine.

Fuel oil viscosity control

Heavy fuel must be heated so its viscosity at the injector is about 10 to 15 centistokes; viscosity, not temperature, is the controlled variable because fuel quality varies.

Boiler feedwater treatment

Chemical dosing to maintain alkalinity around pH 10.5 to 11.5 and phosphate for scale control, with continuous blowdown limiting dissolved solids and chloride testing detecting condenser leakage.

Oily water separator limit

Equipment that separates oil from bilge water and must alarm and automatically stop discharge when effluent exceeds 15 parts per million, as required by MARPOL Annex I.

Steering gear requirements

Tankers require two independent power-actuating systems with changeover within 45 seconds; the rudder must move from 35 degrees one side to 30 degrees the other within 28 seconds.

Three-phase power formula

Real power in watts equals the square root of three times line voltage times line current times power factor, distinguishing kilowatts delivered from kilovolt-amperes apparent.

Alternator paralleling conditions

Before closing the breaker, voltage, frequency, phase sequence and phase angle must match; the synchroscope should rotate slowly in the fast direction at the moment of closure.

Insulation resistance minimum

For a 440 volt system, insulation resistance should be at least one megohm when tested at 500 volts direct current with the circuit isolated and earthed before and after.

Loss of discrimination

A protection grading failure in which an upstream breaker trips before the downstream device clears a fault, causing unnecessary loss of supply to healthy circuits and possible blackout.

Free surface effect

The reduction in metacentric height caused by liquid with a free surface in a partly filled tank, proportional to the second moment of area of that surface divided by displacement.

Metacentric height

The distance between the centre of gravity and the transverse metacentre, equal to KM minus KG; a positive value produces a righting moment and positive initial stability.

Collision bulkhead position

A watertight bulkhead located not less than 0.05 and not more than 0.08 of the ship's length from the forward perpendicular, required for subdivision and damage survival.

Engineer of the watch handover

A formal transfer of responsibility covering running machinery, fuel and water states, temperatures and pressures, standing orders, and any defects or ongoing operations requiring attention.

MARPOL sulphur limits

The global limit on fuel sulphur content is 0.50 percent by mass, reduced to 0.10 percent in Emission Control Areas; equivalent compliance may be by approved exhaust gas cleaning.

NOx Tier III

Emission standard applying to marine diesel engines installed on ships built on or after 1 January 2016 when operating in NOx Emission Control Areas, met by internal measures or selective catalytic reduction.

Ballast water management

Ships must follow an approved plan using exchange or treatment to limit transfer of invasive species, with a record book and discharge standards under the Ballast Water Management Convention.

Enclosed space entry test

Before entry, the atmosphere must show oxygen between 19.5 and 23.5 percent with hydrocarbons and toxic gases within limits, a permit issued and a standby man posted.

Unbalance vibration signature

A rotating machine with mass unbalance shows a dominant vibration peak at once per revolution, whereas misalignment typically produces a strong peak at twice per revolution.

Crankcase oil analysis

Laboratory testing of lubricating oil for water, insolubles, viscosity change and wear metals such as iron, copper, chromium, lead and tin, interpreted mainly by trend rather than single values.

Low-hydrogen electrodes

Welding consumables that must be stored and dried to specification before use; they limit hydrogen in the weld and prevent hydrogen-induced cracking in high-strength steel.

STCW rest hour requirement

Watchkeeping engineers must have a minimum of ten hours rest in any 24-hour period and 77 hours in any seven-day period, recorded and available for inspection.

ISM Code purpose

A framework requiring documented safety procedures, a designated person ashore, internal audits and management review to ensure safe operation and pollution prevention on board.

Oil record book entries

A statutory record of oil transfer, disposal and machinery space operations, entered at the time of the operation and signed by the officer in charge; false entries are a criminal offence.