MARINA OIC-EW Theoretical Exam flashcards

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

Mean indicated pressure

Average pressure acting on the piston during the power stroke, derived from the indicator diagram area divided by stroke volume; multiplied by swept volume and speed it gives indicated power.

Specific fuel consumption

Fuel mass burned per unit of brake power per hour, usually g/kWh; calculated as fuel flow in kg/h divided by brake power in kW, and used to trend engine efficiency.

Turbocharger surge

Unstable operation where compressor delivery pressure exceeds what the turbine can absorb, causing violent air pulsation and noise; typically triggered by rapid load change, fouled turbine or blocked air cooler.

Crankcase oil mist detector

Device that samples crankcase atmosphere and alarms when oil mist concentration rises, warning of a hot spot before an explosion; the crankcase must not be opened until it has cooled.

Boiler flame failure trip

Safety interlock that closes the fuel oil valve when the flame scanner loses the flame signal, preventing fuel from accumulating in the furnace and causing a furnace explosion on relight.

Reverse power relay

Protection that trips a generator breaker when the machine draws power from the busbar instead of supplying it, protecting the prime mover from damage caused by motoring.

Preferential trip

Load-shedding arrangement that automatically disconnects non-essential circuits such as galley and air conditioning when generator capacity is lost, keeping propulsion and steering supplied.

Insulated distribution system

An IT system in which the neutral is not earthed, so a single earth fault causes no trip; a second fault on another phase would create a short circuit, so faults are located promptly.

Crankshaft deflection measurement

Reading taken between crank webs with a dial gauge at defined crank positions; changing readings indicate main bearing wear or bedplate distortion and are compared with maker's limits.

Planned maintenance system

Record of every maintenance job with its interval in running hours or calendar time, last completion and next due date, signed off by the responsible engineer.

Cylinder liner wear rate

Increase in liner diameter per running hour, measured with a dial gauge at set positions; rising rate points to poor lubrication, wrong fuel or excessive scavenge air.

Permit to work

Formal written authorisation for hazardous tasks such as hot work or enclosed space entry, listing precautions, gas test results, isolation, and the person in charge.

STCW rest hour limits

Minimum 10 hours rest in any 24-hour period and 77 hours in any 7-day period; rest may be split into at most two periods, one of which is at least 6 hours.

Master's overriding authority

The master may take any decision, including deviation and requesting assistance, needed to preserve life and the ship, and is not constrained by the owner from doing so.

Enclosed space entry precautions

Atmosphere tested for oxygen, hydrocarbons, carbon monoxide and hydrogen sulphide before and during entry, continuous ventilation, a permit, and a standby person at the entrance.

Metacentric height

Vertical distance between the centre of gravity and the metacentre, calculated as KM minus KG; positive GM gives initial stability and a stiff ship, small GM a tender ship.

Free surface effect

Loss of effective stability caused by liquid moving freely in a partly filled tank; the correction equals the second moment of area of the free surface times density divided by displacement.

Angle of loll

List of a ship with negative initial stability, which may flop from one side to the other; corrected by lowering the centre of gravity and eliminating free surfaces.

Hogging and sagging

Longitudinal bending where hogging puts the deck in tension and the bottom in compression, while sagging reverses this; both add to the still-water bending moment.

MARPOL Annex VI sulphur limit

Fuel sulphur content capped at 0.50% m/m globally from 1 January 2020 and 0.10% in emission control areas, met by compliant fuel, scrubber or alternative fuel.

Oil Record Book

Mandatory record of machinery space oil operations including ballasting, cleaning, separator discharge and disposal ashore; entries must be made without delay and are subject to inspection.

ISM Code

International Safety Management Code requiring a documented safety management system, a designated person ashore, internal audits and corrective action, under SOLAS Chapter IX.

MLC 2006

Maritime Labour Convention setting minimum standards for seafarer employment agreements, hours of rest, accommodation, food, repatriation and complaint procedures, verified by certificate and declaration.

Fire classes

Class A solids, B flammable liquids, C gases, D metals and F cooking oils; water must not be used on B, C, D, F or on live electrical equipment.

Fixed CO2 release procedure

Confirm all persons accounted for, seal the space and shut ventilation before release; the pre-discharge alarm sounds and CO2 displaces oxygen, making the space lethal.

Emergency generator start time

Under SOLAS the emergency generator must start automatically and supply emergency loads such as steering, lighting, radio and fire pump within 45 seconds of main power failure.

Man overboard first actions

Put the helm hard over to swing the stern clear, release a lifebuoy with light and smoke, sound three long blasts, post a lookout, and commence the recovery turn.

Bridge control changeover

Before transferring control to the bridge, test the telegraph both ways, confirm starting air pressure and fuel rack operation, and ensure the engine room is manned for manoeuvring.

Closed-loop communication

Order is given, repeated back by the receiver, and confirmed by the giver; unclear instructions are challenged, reducing error during manoeuvring and emergency response.

Steering gear test requirement

Main and emergency steering gear must be tested within 12 hours before departure, checking both power units, alarms and the emergency steering position, with the test recorded.

Purifier gravity disc selection

Disc chosen according to fuel density and separation temperature; too large a disc allows water carry-over into the oil, too small a disc loses oil to the sludge side.

PID controller terms

Proportional band sets response to error, integral time removes steady-state offset, derivative time responds to rate of change; excessive gain causes oscillation and excessive integral causes slow hunting.