MARINA OIC-EW Theoretical Exam cheat sheet

Two-stroke slow-speed diesel: scavenge air enters via ports at the lower liner, exhaust leaves via a central hydraulically actuated exhaust valve; uniflow scavenging needs only one exhaust valve per cylinder.

Indicator diagram: mean indicated pressure (mip) = area of p–V diagram divided by stroke volume; indicated power per cylinder = mip × A × L × n × (cycles per rev), with n in rev/s.

Specific fuel consumption (SFOC) = fuel mass flow (kg/h) ÷ brake power (kW); modern large two-strokes typically 160–180 g/kWh at MCR, rising at part load.

Air/fuel stoichiometry: about 14.5 kg air per kg diesel for complete combustion; scavenge air excess of 2.0–2.5 times stoichiometric is normal at full load.

Turbocharger surge occurs when compressor delivery pressure exceeds what the turbine can sustain; typical triggers are rapid load change, fouled turbine, or air cooler blockage.

Crankcase explosion prevention: oil mist detector alarm at about 2.5% oil mist by volume (lower alarm) with main alarm/auto slowdown at higher concentration; do not open crankcase doors after an alarm until cooling.

Auxiliary boiler: safety valve set at or below design pressure, two independent low-water level trips, and a flame failure trip that closes the fuel valve within a few seconds of flame loss.

Fuel oil viscosity control: HFO heated to give 10–15 cSt at the injector inlet; excessive viscosity causes poor atomisation and afterburn, too low viscosity causes pump and injector wear.

Three-phase power: P = √3 × V_line × I_line × power factor; for a 440 V, 100 A, 0.85 pf load, P ≈ 64.8 kW.

Insulation resistance: minimum acceptable for a 440 V system is generally 1 MΩ at 500 V DC megger test; readings below that require investigation before energising.

Alternator paralleling: match voltage, frequency, phase sequence and phase angle before closing the breaker; adjust governor (kW sharing) and excitation (kVAr sharing) after synchronising.

Reverse power protection trips a generator that motored (typically 2–6% of rated kW with time delay) to prevent turbine or prime-mover damage.

Preferential trip (load shedding) disconnects non-essential loads such as galley, air conditioning and some ventilation when one generator is lost, keeping propulsion and steering supplied.

Earth fault on an insulated (IT) distribution system: a single earth fault does not trip; locate it promptly because a second fault on another phase creates a phase-to-phase short.

Battery/charger safety: lead-acid cells emit hydrogen; ventilation and no naked flame; equalising charge voltage per cell is higher than float voltage and must be monitored for temperature.

Programmable logic controller (PLC) inputs: 4–20 mA current loop is preferred over voltage for analogue sensors because it is immune to cable resistance and detects open circuit at 0 mA.

Planned maintenance system (PMS) records each job with interval (running hours or calendar), last done, next due, and a sign-off by the responsible engineer; overdue items must be reported.

Critical spares are identified by risk: items whose failure stops propulsion or steering (fuel injection valves, cylinder heads, sea-water pump seals, steering gear pumps) get priority stock levels.

Cylinder liner wear: measure with a dial gauge at defined positions and record; maximum allowable wear rate for large two-strokes is typically around 0.05–0.1 mm per 1000 hours; excessive wear points to lubrication or fuel quality.

Crankcase oil testing: check viscosity, water content, total base number (TBN), insolubles and wear metals (Fe, Cu, Pb, Sn) at defined intervals; trend results rather than judging a single sample.

Bearing clearance check: use plastic gauge (Plastigauge) or lead wire for shell bearings; compare against maker's limits, and check crankshaft deflection for main bearing and bedplate alignment.

Hot work and enclosed space entry require a permit to work, gas testing (O2 20.9%, hydrocarbons <1% LFL, no H2S/CO), standby man and communication; never enter alone.

Torque values: always torque to the maker's figure with a calibrated wrench; for cylinder head bolts follow the specified tightening sequence and stages (often three stages plus a final angle).

Defect reporting: any defect affecting safety, pollution prevention or class must be recorded, reported to the master/company and, where applicable, to class and flag State; temporary repairs need approval.

Rest hours under STCW/MLC: minimum 10 hours rest in any 24-hour period and 77 hours in any 7-day period; rest may be divided into no more than two periods, one at least 6 hours.

Watchkeeping fitness: the officer in charge of a watch must not be under the influence of alcohol (blood alcohol typically 0.05% or 0.25 mg/l breath limit under STCW) or drugs impairing performance.

Master's authority: the master may take any action necessary to preserve life, ship and cargo, and may deviate to save life at sea; the master's overriding obligation is safety of persons.

Enclosed space entry: atmosphere must be tested before and during entry, continuous ventilation maintained, permit issued and a responsible person stationed at the entrance.

Fatigue management: record rest hours daily, plan watch rotations to avoid more than 6 hours on watch without a break, and report fatigue hazards through the safety management system.

Medical care: the ship must carry a medical guide and medicines per flag requirements; the master may request radio medical advice (TMAS) and must record treatment in the medical log.

Muster list: each person has a designated station and duties; drills are required at intervals (abandon ship and fire drills at least monthly for most ships under SOLAS).

Harassment and bullying: MLC 2006 requires complaint procedures onboard and ashore; seafarers have the right to report without victimisation.

GM (metacentric height) = KM − KG; positive GM gives initial stability; a stiff ship has large GM (short roll period, harsh motion), a tender ship has small GM.

Free surface effect: FSC = i × ρ / (Δ) where i is the second moment of area of the free surface; divided tanks reduce free surface and increase effective GM.

Angle of loll: a ship with negative GM lists to either side and may flop from one side to the other; correct by lowering KG (ballast low down) and removing free surfaces, not by shifting weight across.

Load line marks: the summer load line is the reference; tropical, winter, fresh water and timber allowances shift the permitted draught; the deck line and load line disc must be permanently marked.

Longitudinal strength: still-water bending moment plus wave-induced bending; hogging puts the deck in tension, sagging puts the bottom in tension; load distribution must stay within class limits.

Bulkhead and watertight integrity: collision bulkhead located at a minimum distance from the forward perpendicular (typically 0.05L to 0.08L); all watertight doors closed at sea unless working.

Damage stability: the vessel must survive flooding of assumed compartments; cross-flooding arrangements and closing appliances are part of the approved damage control plan.

Tonnage: gross tonnage is a measure of enclosed volume (not weight) used for manning and fees; net tonnage is the earning capacity measure; neither equals displacement.

MARPOL Annex I (oil): 15 ppm oily water separator discharge limit; Annex II noxious liquid substances; Annex III harmful packaged goods; Annex IV sewage; Annex V garbage with a total ban on plastics; Annex VI air pollution (SOx, NOx, EEDI).

MARPOL Annex VI sulphur: 0.50% m/m global limit from 1 January 2020 and 0.10% in ECAs; compliance by low-sulphur fuel, scrubber or alternative fuel, with records in the oil record book and BDN retained 3 years.

Oil Record Book Part I (machinery space) entries must be made without delay for each operation: ballasting, cleaning, discharge through 15 ppm equipment, disposal ashore; false entries are a criminal offence in many jurisdictions.

STCW 2010 Manila Amendments: certificates of competency valid up to 5 years, revalidation requires sea service or refresher training, and basic safety training (PST, FPFF, EFA, PSSR) must be current.

SOLAS Chapter IX/ISM Code: safety management system with documented procedures, designated person ashore, master's responsibility and authority, internal audits and corrective action.

MLC 2006: minimum age 16 (18 for night work/hazardous work), seafarer employment agreement, repatriation, accommodation and food standards, and complaint procedures; certificate of maritime labour compliance plus declaration of maritime labour compliance.

COLREG Rule 5: proper lookout by sight and hearing and all available means; Rule 6 safe speed; Rule 8 action to avoid collision must be positive, made in ample time and large enough to be readily apparent.

Port State Control: inspectors may detain for deficiencies; the ship must carry valid statutory certificates and class certificates, and the master must cooperate and record the inspection in the appropriate log.

Fire triangle: fuel, oxygen and heat; extinguishing by removing one side. Class A (solids), B (flammable liquids), C (gases), D (metals), F (cooking oils); water is forbidden on B, C, D, F and on live electrical equipment.

Fixed CO2 system: release only after all persons accounted for and space sealed and ventilation shut; CO2 displaces oxygen and is lethal in occupied spaces; the alarm sounds before release.

Fire main pressure and hydrants: at least two jets of water from different hydrants must reach any part of the ship; the emergency fire pump is located outside the machinery space.

Abandon ship: distress signal, muster at stations, lifeboat/liferaft launch, and the order to abandon is given only by the master; the EPIRB and SART are activated as directed.

Man overboard: immediate helm hard over to swing the stern away from the person, release lifebuoy with light/smoke, sound three long blasts, post lookout, commence Williamson turn and inform master.

Oil spill response: stop the source, contain with booms, use SOPEP/Emergency Plan, notify the master and authorities, and record actions; never use dispersants without approval.

Emergency generator: must start and supply emergency loads (steering, emergency lighting, radio, fire pump) automatically within 45 seconds of main power failure under SOLAS.

Drills and training: fire and abandon-ship drills monthly, enclosed space rescue drills as required, and records kept in the official logbook and training manual.

Engine room watch handover: report machinery condition, ongoing work, defects, alarms and unusual readings; never hand over during a critical manoeuvre without the chief engineer's approval.

Unattended machinery space (UMS): alarm and safety systems must be tested and proven; the duty engineer must be within call and respond to alarms within the specified time.

Bridge control: before switching to bridge control, test the engine telegraph, confirm starting air pressure and fuel rack operation, and ensure the engine room is manned for manoeuvring.

Standby engine: main engine on standby at least one hour before departure and during pilotage; the engine room must be manned and the telegraph tested both ways.

Resource management: use closed-loop communication (order, repeat back, confirm), challenge unclear instructions, and assign a person to monitor the engine controls during manoeuvres.

Alarm response: acknowledge, identify the alarm, take immediate safe action, then investigate; do not silence or inhibit alarms to clear a nuisance without recording and reporting.

Bunkering: pre-transfer checklist, agreed transfer rate and topping-off rate, scuppers plugged, continuous watch at the manifold and tanks, and emergency stop agreed before starting.

Machinery space flooding: bilge high-level alarms, emergency bilge suction, and the ability to isolate the sea-water system; know the location of the emergency suction valve.

Steering gear: SOLAS requires two independent power units; the main and emergency steering gear must be tested within 12 hours before departure, with the test recorded.

Steering gear failure: change to the second pump/unit, switch to emergency steering from the steering flat, inform the bridge, and exhibit the appropriate signals.

Steering gear hydraulic oil: check level, temperature, leakage and pump pressure; a hydraulic lock or air in the system causes sluggish or noisy response.

Air compressor: intercooler and aftercooler drain traps must be checked; high discharge temperature trips protect against valve or cooler failure; safety valves tested periodically.

Fresh water generator: output depends on jacket water temperature and vacuum; scale on the evaporator reduces output and requires chemical cleaning.

Purifier: correct gravity disc selection for the fuel density and temperature; incorrect disc causes water carry-over or oil loss to the sludge side.

Sewage treatment plant: check aeration, chlorine/disinfectant dosing, and discharge limits; the plant must be approved and not discharge untreated sewage within restricted areas.

Sensor ranges: a 4–20 mA transmitter with a 0–10 bar range gives 4 mA at 0 bar and 20 mA at 10 bar; a reading of 12 mA corresponds to 5 bar.

PID control: proportional band, integral (reset) time and derivative time; too much proportional gain causes oscillation, too much integral causes slow hunting, derivative is rarely used on noisy signals.

Alarm and trip philosophy: alarms warn, trips protect; safety-critical trips (overspeed, low lube oil pressure, high jacket water temperature) must not be bypassed without a documented risk assessment.

Two-wire vs three-wire resistance temperature detector (RTD): a three-wire Pt100 compensates for cable resistance; a two-wire installation introduces an error proportional to lead resistance.

Emergency stop and interlock circuits are fail-safe: they are wired so that loss of power or a broken wire produces the safe state (trip).

Insulation monitoring on an IT system: the monitor injects a small DC or low-frequency signal and alarms on the first earth fault; locate the fault by sectional isolation.

Blackout recovery: the emergency generator starts automatically, the main switchboard is re-energised in sequence, and large loads are reconnected in stages to avoid a second trip.