Maskinbefal flashcards

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

Two-stroke uniflow scavenging

Air enters through scavenge ports at the bottom of the liner and exhausts through a central exhaust valve at the top; a single working stroke per revolution gives high power density.

Propeller law

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

Specific fuel consumption

Fuel mass burned per unit of shaft energy produced, expressed in g/kWh; it rises at low load, which is why slow steaming needs engine de-rating or part-load tuning.

Cylinder lubricator total loss

Large two-stroke engines supply cylinder oil through dedicated lubricators; the oil is consumed in the cylinder and not returned to a sump, unlike trunk-piston engine crankcase oil.

Metacentric height GM

GM equals KM minus KG; a positive value produces a righting moment and initial stability, while a negative value causes the ship to loll to one side.

Free surface correction

The reduction in effective GM caused by liquid moving in partly filled tanks; it is proportional to the second moment of the free surface and inversely proportional to displacement.

Angle of loll

An unstable equilibrium angle occurring when GM is negative; it is corrected by lowering the centre of gravity, typically with double-bottom ballast, not by adding top weight.

Summer load line

The load line mark for summer zone loading, measured from the deck line; tropical freeboard is higher and winter freeboard lower than the summer mark.

Hogging and sagging

Hogging puts the deck in tension and the bottom in compression, while sagging reverses this; load distribution must keep bending moments within class limits.

PMS running-hour interval

Planned maintenance jobs are triggered by accumulated running hours or calendar time; overdue items are recorded and reported to the technical manager rather than silently deferred.

Oil mist detector alarm

A detector sensing oil mist in the crankcase indicates a hot spot or bearing distress; the engine is stopped and the cause investigated before restarting.

Cylinder liner wear measurement

Liner wear is measured with a dial gauge at top, middle and bottom positions; excessive wear or ovality indicates abnormal lubrication, fuel quality or load distribution.

Individual exhaust temperature

Comparing exhaust temperatures per unit at equal load identifies a faulty injector, delayed injection timing or a worn fuel pump on a specific cylinder.

Turbocharger fouling symptoms

Fouling raises exhaust gas temperature and lowers scavenge air pressure; water washing of turbine and compressor restores efficiency and reduces fuel consumption.

Reverse power protection

A generator protection that trips the breaker when power flows into the generator, preventing it from motoring if its prime mover loses power.

Synchronisation conditions

Before paralleling generators, voltage, frequency, phase sequence and phase angle must match; the synchroscope should be at twelve o'clock when the breaker closes.

Insulation resistance test

A 500 V DC megohmmeter measures insulation resistance; readings below about 1 MΩ on a 440 V system require investigation, and values are corrected to 40 °C for trending.

PID integral action

Integral action accumulates the error over time and removes steady-state offset; derivative action responds to the rate of change but amplifies measurement noise.

Fire triangle

Combustion requires fuel, oxygen and heat; extinguishing removes at least one leg by cooling, smothering or chemical inhibition.

Fixed CO2 release

Releasing fixed CO₂ into a machinery space requires a warning alarm, evacuation and head count; the gas displaces oxygen and is lethal to personnel.

Enclosed space entry test

Before entry, oxygen must be about 20.9%, hydrocarbons within limits and hydrogen sulphide below 5 ppm; a permit and a standby man at the entrance are required.

Emergency generator test

The emergency generator is tested weekly under load; it must start automatically on main power failure and supply emergency lighting, steering and radio within 45 seconds.

Fifteen ppm oily water separator

Machinery-space bilge water must pass through 15 ppm separation equipment fitted with an alarm and automatic stopping device before any discharge is permitted.

Oil Record Book Part I

Records bilge transfers, sludge disposal, separator operation and bunkering; entries are signed by the person in charge and master and retained for three years.

MARPOL Annex V plastics

Plastics may never be discharged into the sea; food waste is dischargeable beyond 3 nm when comminuted or 12 nm when not, and a garbage record book is kept.

Sulphur Emission Control Area

In ECAs the sulphur content of fuel oil is limited to 0.10%, compared with 0.50% globally; a Bunker Delivery Note and retained sample are required.

STCW rest hours

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

ISM Code non-conformity

A documented deviation from the safety management system; it is recorded, investigated for root cause and closed out with corrective action verified by audit.

Certificate validity period

SOLAS and MARPOL certificates are normally valid for a maximum of five years, subject to annual and intermediate surveys by flag state or class.

Permit to work

A formal authorisation for hot work, enclosed space entry or electrical isolation; it is signed by the responsible officer and valid only for the stated task and period.

Closed-loop communication

The sender gives an order, the receiver repeats it back, and the sender confirms; this technique reduces misunderstanding during machinery operations and emergencies.

Just culture

A reporting culture that distinguishes human error from at-risk behaviour and reckless violation, encouraging near-miss reporting without blame and improving safety performance.