MARINA Chief Mate / Master Theoretical Exam flashcards

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

Mercator sailing formula

Departure equals difference of longitude multiplied by the cosine of the mean latitude. Use it for moderate latitudes and small longitude changes; for large changes, use great-circle or Mercator sailing to avoid error.

Running fix

A position fix obtained by advancing an earlier line of position by the course and distance run, then crossing it with a later line of position. Accuracy decreases with the distance advanced.

Stowage factor

The volume in cubic metres occupied by one tonne of cargo. Used to calculate the space a cargo will occupy and to compare with the ship's available cargo capacity.

Broken stowage

The space lost between cargo packages, dunnage, and hold irregularities. Expressed as a percentage of the space occupied; it reduces the effective cargo capacity of the hold.

IMDG 'away from'

A segregation term meaning dangerous goods must be stowed at least 3 metres horizontally apart. It is the least restrictive of the four segregation terms in the IMDG Code.

Cargo liquefaction

A phenomenon in which a bulk cargo with high moisture content behaves like a liquid under ship motion. Group A cargoes require a certificate of moisture content and transportable moisture limit.

Fire triangle

The three elements needed for combustion: fuel, oxygen, and heat. Removing any one element extinguishes the fire; this principle underlies all firefighting tactics.

Williamson turn

A man-overboard manoeuvre in which the ship alters hard to one side, then hard to the opposite side, to return to the person's position while leaving the wake clear.

Emergency generator start

SOLAS requires the emergency generator to start automatically and supply the emergency switchboard within 45 seconds of a main power failure. It is tested weekly and run under load monthly.

GM and GZ

GM is the metacentric height, KM minus KG. GZ is the righting lever, approximately GM times the sine of the heel angle for small angles. Positive GM gives positive initial stability.

Free surface effect

The reduction in metacentric height caused by liquid moving freely in a partially filled tank. It is calculated from the free surface moment divided by the ship's displacement.

Angle of vanishing stability

The angle of heel at which the righting lever GZ becomes zero and the GZ curve crosses the axis. Beyond it the ship capsizes unless the heeling moment is removed.

Buys Ballot's law

In the Northern Hemisphere, with your back to the wind, low pressure lies to your left. In the Southern Hemisphere, low pressure lies to your right.

Dangerous semicircle

In a Northern Hemisphere tropical storm, the right-hand side of the storm track, where the wind and the storm's motion combine to give the strongest winds and highest seas.

Significant wave height

The average height of the highest one-third of waves in a sea state. The maximum individual wave may be roughly twice the significant wave height.

Beaufort force 8

A gale, with wind speeds of 34 to 40 knots. It produces moderately high waves with breaking crests and streaks of foam blown along the wind direction.

STCW rest hours

Minimum 10 hours of rest in any 24-hour period and 77 hours in any 7-day period. Rest may be split into no more than two periods, one of at least 6 hours.

Enclosed space entry

Entry into a space with limited ventilation requires atmosphere testing for oxygen, hydrocarbons, and toxic gases, a permit, a standby person, and rescue equipment at the entrance.

Muster list

A document assigning each person on board to a station and duty in an emergency. It is posted in conspicuous places and updated whenever the crew changes.

COLREG Rule 13

The overtaking vessel must keep out of the way of the vessel being overtaken until finally past and clear. An overtaking vessel is one approaching from more than 22.5 degrees abaft the beam.

MARPOL Annex VI sulphur

The global sulphur limit for fuel oil is 0.50% m/m since 1 January 2020, and 0.10% m/m in emission control areas. Compliance may be by low-sulphur fuel or an approved equivalent.

Territorial sea

Under UNCLOS, the belt of sea up to 12 nautical miles from the baseline over which the coastal state has sovereignty, subject to the right of innocent passage.

COLREG Rule 19

In restricted visibility, vessels must proceed at a safe speed and, if a risk of collision exists, take avoiding action. A vessel hearing a fog signal forward of her beam must reduce speed to the minimum.

Two-stroke diesel cycle

A cycle in which each cylinder fires once per revolution, using ports and uniflow scavenging. Large low-speed two-stroke engines are the most efficient type for ship propulsion.

Turbocharger surging

A repeated reversal of airflow through the compressor, often caused by a mismatch between engine load and turbocharger output, fouled components, or a faulty air cooler.

Steering gear test

SOLAS requires the main and auxiliary steering gear to be tested before departure and emergency steering drills to be held every three months.

GMDSS sea area A3

An area covered by an Inmarsat geostationary satellite, excluding A1 and A2 areas. Ships operating in A3 must carry appropriate satellite communication equipment.

EPIRB

An emergency position-indicating radio beacon transmitting on 406 MHz to the COSPAS-SARSAT system. It should be float-free, registered with the national authority, and within battery expiry.

SART

A search and rescue radar transponder operating in the 9 GHz band. It responds to a ship's radar with a series of dots, typically detectable at about 5 to 10 nautical miles.

NAVTEX frequencies

NAVTEX broadcasts maritime safety information on 518 kHz for international English, 490 kHz for national languages, and 4209.5 kHz for long-range HF reception.

ECDIS official data

ECDIS must use official electronic navigational charts or an approved raster chart service. The safety settings and alarms must be set for the planned voyage and monitored.

AIS limitations

AIS transmits identity, position, course, and speed, but it is not a collision-avoidance system. It does not replace radar, visual lookout, or the requirements of the COLREGs.