BD Deck Officer Class 1 (Master) flashcards

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

Meridional parts

The cumulative north-south distance on a Mercator chart measured in minutes of longitude, used to compute Mercator sailing course and distance.

Great circle vertex

The point of highest latitude on a great circle track; found from the initial course and departure latitude, and used to check the track does not exceed safe limits.

CPA and TCPA

Closest point of approach and time to closest point of approach, derived from the relative motion plot on radar or ARPA to judge collision risk.

Rule of twelfths

A method estimating tidal height at intermediate times: cumulative fractions of the range are 1/12, 3/12, 6/12, 9/12, 11/12 and 12/12 over six equal intervals.

Metacentric height GM

The vertical distance between the centre of gravity and the metacentre; positive GM indicates initial stability, negative GM indicates an unstable vessel.

Free surface effect

The apparent rise of the centre of gravity caused by liquid moving freely in a partly filled tank, reducing effective GM and calculated from the tank's second moment of area.

Angle of loll

The angle at which an unstable ship with negative GM comes to rest; it satisfies tan θ = square root of (2 × negative GM divided by BM).

MCTC

Moment to change trim by one centimetre; the trimming moment divided by MCTC gives the change of trim, which is then distributed fore and aft about the centre of flotation.

Stowage factor

The volume in cubic metres occupied by one tonne of a cargo, used with broken stowage allowance to calculate the space a cargo will need.

Transportable moisture limit

The maximum moisture content at which a Group A bulk cargo is considered safe from liquefaction; the actual moisture content must be below the TML before loading.

IMDG segregation codes

Four levels of separation for dangerous goods: away from, separated from, separated by a complete compartment, and separated longitudinally by an intervening complete compartment.

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

The half of a tropical revolving storm where the wind blows toward the storm track; in the Northern Hemisphere this is the right-hand semicircle.

Advection fog

Fog formed when warm, moist air moves over a colder surface and is cooled below its dew point; common over cold ocean currents.

Geostrophic wind

Wind that blows parallel to straight isobars when the pressure gradient force is balanced by the Coriolis force, above the friction layer.

Virtual loss of GM

The reduction in metacentric height when a vessel takes the blocks in dry dock; the upward force at the keel raises the effective centre of gravity.

Master-pilot exchange

A briefing where the pilot and master exchange passage plans, vessel particulars, manoeuvring characteristics and local conditions before pilotage begins.

APEM passage planning

The four stages of voyage planning: appraisal, planning, execution and monitoring, including no-go areas, abort points and contingency anchorages.

STCW rest hours

Minimum 10 hours 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 at least 6 hours.

Williamson turn

A man-overboard manoeuvre: hard over one helm, then hard over the other after 60 degrees, to return the vessel on a reciprocal track.

GMDSS distress alert

A DSC alert on VHF channel 70 or MF 2187.5 kHz, or an Inmarsat alert, followed by voice distress communication on VHF 16 or MF 2182 kHz.

Steering gear drill

A SOLAS-required drill, held every three months, testing changeover from main to emergency steering and communication between bridge and steering flat.

Indicator diagram

A pressure-volume plot of the main engine cylinder, used to calculate indicated power and to detect faults in compression, injection and exhaust timing.

Sulphur limit

MARPOL Annex VI caps fuel sulphur at 0.50 percent m/m globally, and 0.10 percent in emission control areas, unless an approved equivalent method is used.

Innocent passage

The right of ships to pass through the territorial sea without threatening the peace, good order or security of the coastal State, subject to its laws.

ISM Code documents

The Document of Compliance is issued to the company and the Safety Management Certificate to the ship after verification of the safety management system.

Oil record book

A mandatory record of oil and oily water operations; Part I covers machinery spaces and Part II covers cargo and ballast operations, signed by the master.

Annex V garbage discharge

Plastics are never discharged; food waste may be discharged at least 12 nautical miles from land, or 3 nautical miles if comminuted, with stricter special-area rules.

Ballast water D-2 standard

The treatment standard limiting viable organisms in discharged ballast water, applied under the Ballast Water Management Convention as an alternative to exchange.

Situational leadership

A model matching leader style (telling, selling, participating, delegating) to the follower's competence and commitment for the task at hand.

Just culture

A safety culture where errors are reported and learned from without blame, while reckless or intentional violations are still subject to disciplinary action.

Bridge resource management

The coordinated use of all bridge resources, including people, equipment and information, to maintain situational awareness and safe decision-making.