Norway Deck Officer Class 1 (Master Mariner) flashcards

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

Great-circle distance formula

Distance in nautical miles equals 60 times the angular distance in degrees, found from the spherical cosine formula using the latitudes and the difference in longitude of the two positions.

Mercator sailing

A method of solving a course and distance on a Mercator chart using the difference in meridional parts and the difference in longitude, with departure obtained from the meridional parts and the course angle.

Celestial intercept

The difference between the observed altitude and the calculated altitude, drawn from the assumed position toward the geographic position if positive and away if negative, giving one line of position.

Rule of twelfths

A tidal height approximation dividing the range into twelve parts: one, two, three, three, two and one twelfth in each successive sixth of the interval between high and low water.

Buys Ballot's law

In the Northern Hemisphere, with your back to the wind, low pressure lies to your left and slightly ahead; in the Southern Hemisphere it lies to your right.

Dangerous semicircle

The half of a tropical cyclone to the right of its track in the Northern Hemisphere, where the wind and the storm motion combine and the wind veers as the storm passes.

Advection fog

Fog formed when warm, moist air moves over a colder sea surface and is cooled below its dew point, common over cold currents and in spring and early summer.

Significant wave height

The mean height of the highest third of the waves in a sea state, used as the standard measure of sea severity and roughly half the maximum wave height in a record.

Metacentric height

The distance between the centre of gravity and the transverse metacentre; a positive value gives initial stability and the righting lever equals GM times the sine of the heel angle for small angles.

Free surface correction

A reduction in effective metacentric height caused by liquid free to move in a partly filled tank, calculated from the second moment of the free surface area and the liquid density.

Load line freeboard

The distance measured vertically at the ship's side from the deck line to the summer load line, assigned by the flag administration and marked with seasonal allowances.

Pivot point

The point about which a ship turns; it lies near midships at rest and moves forward with headway and aft with sternway, so the stern swings out first when going astern.

Bank effect

The interaction between a ship and a nearby bank: suction at the bow and cushioning at the stern, tending to shear the bow toward the bank and requiring a course correction away.

Squat

The increase in draft and trim caused by the flow of water past the hull, greatest in shallow water and at high speed, approximated in open water by block coefficient times speed squared over one hundred metres.

STCW rest hours

A minimum of ten hours of rest in any twenty-four hour period and seventy-seven hours in any seven-day period, divided into no more than two periods, one of at least six hours.

Bridge standing orders

Written instructions signed by the master that define when the officer of the watch must call the master, take action or deviate from the passage plan.

Overtaking rule

Under Rule 13, any vessel overtaking any other must keep out of the way until finally past and clear, regardless of the other vessel's type or activity.

Crossing rule

Under Rule 15, a power-driven vessel with another on her own starboard side must keep out of the way, and the stand-on vessel keeps her course and speed.

Restricted visibility rule

Under Rule 19, no vessel is stand-on; every vessel proceeds at a safe speed, and a vessel detecting another by radar alone must take avoiding action in ample time.

Specific fuel consumption

The fuel mass burned per unit of shaft work, typically one hundred sixty to one hundred eighty grams per kilowatt-hour for a modern slow-speed two-stroke engine.

Steering gear performance

SOLAS requires two independent power units and a rudder movement from thirty-five degrees one side to thirty degrees the other within twenty-eight seconds with one unit running.

IMDG segregation terms

The code uses away from, separated from, separated by a complete compartment or hold from, and separated longitudinally by an intervening complete compartment or hold from.

Transportable moisture limit

The maximum moisture content of a group A solid bulk cargo at which it is considered safe from liquefaction during the voyage, certified by the shipper before loading.

Innocent passage

Navigation through the territorial sea that is not prejudicial to the peace, good order or security of the coastal state; submarines must navigate on the surface and show their flag.

MARPOL Annex VI sulphur limits

The global limit is zero point five zero per cent mass by mass, and the limit in emission control areas is zero point one zero per cent; the Mediterranean became a sulphur ECA on 1 May 2025.

Fire tetrahedron

The four elements needed for combustion: fuel, oxygen, heat and the chemical chain reaction; removing any one of them extinguishes the fire.

SOPEP

The shipboard oil pollution emergency plan required by MARPOL Annex I, containing the contact list, the response actions and the reporting procedures for a spill.

Closed-loop communication

A communication protocol in which the receiver repeats the message back and the sender confirms it, used for orders and for helm and engine commands.

Just culture

A safety culture that distinguishes honest error from reckless or intentional behaviour, encourages reporting and protects reporters while reserving blame for wilful acts.

Demurrage

The agreed daily rate payable by the charterer for time beyond the allowed laytime for loading or discharging, as set out in the charter party.

Off-hire

A clause in a time charter under which hire stops when the vessel is unable to perform the service because of breakdown, dry-docking or another defined deficiency.