GMA CoC EOOW flashcards

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

Dead-man alarm

A UMS watch alarm that requires the engineer to reset it at set intervals; failure to reset escalates to the engineer's cabin and then the bridge.

Standby engine status

A condition where the main engine is ready to manoeuvre at short notice; steering gear is tested, and the bridge is informed of readiness.

Mip formula

Mean indicated pressure = area of the indicator diagram divided by its length, expressed in bar; it represents the average pressure on the piston during one cycle.

Indicated power formula

IHP = (mip × L × A × N × n) / 60, where L is stroke, A is piston area, N is rpm, and n is the number of cylinders for a two-stroke engine.

Turbocharger surging

Reversal of airflow through the compressor, usually caused by fouled turbine or compressor, air cooler restriction, or a rapid load change; reduce load and investigate.

Two-stroke scavenging

Uniflow scavenging uses air ports at the lower liner and an exhaust valve at the head; scavenge air pressure indicates turbocharger and port condition.

Pump affinity laws

For a centrifugal pump: flow is proportional to speed, head to speed squared, and power to speed cubed; used for impeller trimming and VFD control.

NPSH available

The suction head available at the pump inlet minus the vapour pressure head of the liquid; cavitation occurs when it falls below NPSH required.

Steering gear test

Before departure, full rudder movement is tested with both pumps and power supplies, and an emergency steering drill is held within 12 hours of departure.

Boiler water treatment

Phosphate controls scale, hydrazine or sulphite scavenges oxygen, and regular blowdown controls dissolved solids; all are monitored by testing.

4-20 mA loop

A standard instrumentation signal where 4 mA is the zero or live-zero value and 20 mA is full scale; 0 mA indicates a broken loop.

PID proportional band

The percentage of error that produces a 100% change in controller output; it equals 100 divided by the controller gain.

Synchroscope use

It shows the phase difference between an incoming generator and the busbar; the breaker is closed when the pointer is at 12 o'clock.

Star-delta starter

A motor starter that connects the winding in star during run-up and in delta for running, reducing starting current to about one-third of DOL.

Micrometer least count

For a 0-25 mm metric micrometer, the least count is 0.01 mm; the reading is the main scale plus the thimble scale times least count.

Vernier caliper least count

The smallest main scale division divided by the number of vernier divisions; typically 0.02 mm on a metric caliper.

Austenitic stainless steel

Grades 304 and 316 are austenitic; 316 contains molybdenum for improved resistance to chloride pitting in marine environments.

Sacrificial anode replacement

Zinc or aluminium alloy anodes protect steel by cathodic protection; they are renewed when about 50% consumed or per class requirements.

Metacentric height GM

GM = KM − KG; a positive GM gives stable equilibrium, while a negative GM causes a list to one side and risk of capsize.

Free surface correction

FSC = (i × ρ) / Δ, where i is the second moment of area of the free surface, ρ is liquid density, and Δ is displacement; it reduces effective GM.

Collision bulkhead position

It must be at least 0.05L (or 10 m, whichever is less) from the forward perpendicular and not more than 0.08L (or 0.05L + 3 m).

GZ curve area criterion

The area under the righting lever curve up to 30 degrees must be at least 0.055 metre-radians under the IMO intact stability criteria.

STCW sea service requirement

STCW 2010 requires at least 12 months of approved seagoing service for certification as Officer in Charge of an Engineering Watch.

MARPOL Annex VI sulphur limits

The global sulphur limit is 0.50% m/m from 1 January 2020, and 0.10% m/m within Emission Control Areas.

Oil Record Book Part I

It records machinery space oil operations; entries are signed by the officer in charge and each page is signed by the Master.

ISM internal audit interval

The Safety Management System requires internal audits at intervals not exceeding 12 months, with a designated person ashore overseeing compliance.

Enclosed space entry testing

Entry requires oxygen at 20.9%, LEL below 1%, hydrogen sulphide below 5 ppm, and carbon monoxide below 5 ppm, with continuous ventilation.

Fire triangle

Combustion requires fuel, oxygen, and heat; removing any one extinguishes the fire. CO2 displaces oxygen, foam blankets fuel, and dry powder interrupts the chain reaction.

Emergency fire pump

It is located outside the machinery space, must deliver at least two jets of water, and is tested at monthly intervals.

STCW rest hours

A minimum of 10 hours rest in any 24-hour period and 77 hours in any 7-day period; rest records must be maintained on board.

Closed-loop communication

The receiver repeats the message back to the sender to confirm understanding; this reduces errors in watch handover and manoeuvring orders.

Permit-to-work system

It is required for hot work, enclosed space entry, working aloft, and electrical isolation; the authorizing officer signs the permit before work starts.