Norway Deck Officer Class 5 flashcards

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

Meridional parts formula

MP = 7915.7 × log10[tan(45° + lat/2)] − 23.0 × sin(lat), expressed in minutes of arc; used in Mercator sailing to relate latitude difference to longitude difference.

Great-circle initial course

cos C = (sin φ2 − sin φ1·cos D)/(cos φ1·sin D), where D is the great-circle distance; the result gives the initial course from the departure point.

Rule of twelfths

Tidal height change over six equal intervals from slack water follows cumulative fractions 1, 3, 6, 9, 11, and 12 twelfths of the tidal range.

Radar range resolution

The minimum separation at which two targets on the same bearing are displayed separately; it depends mainly on pulse length and is approximately c × pulse length / 2.

Metacentric height GM

GM = KM − KG. Positive GM means the vessel is initially stable; GZ = GM × sin θ for small angles of heel. GM is reduced by free surface effect.

Free surface correction

FSC = (i × ρ)/Δ, where i is the second moment of area of the free surface and ρ the liquid density. It reduces effective GM but does not change KG.

Change of trim formula

Change of trim = (w × d)/MCTC, where w is the weight shifted, d the longitudinal distance moved, and MCTC the moment to change trim one centimetre.

Fresh water allowance

FWA = Δ / (4 × TPC), where Δ is displacement and TPC tonnes per centimetre immersion. It is the amount the load line may be submerged in fresh 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.

Advection fog

Fog formed when warm, moist air moves over a colder surface and is cooled below its dew point; it can persist with moderate wind and is common over cold currents.

Tropical storm warning signs

Falling barometric pressure, long swell from a consistent direction, cirrus cloud streaks, and a 3-hourly pressure fall of 1–2 hPa or more suggest an approaching tropical storm.

Pivot point

The point about which a vessel rotates during a turn. At rest it is near midships; with headway it moves toward the bow, and with sternway it moves aft.

Squat effect

A decrease in under-keel clearance caused by water flow around the hull; it increases with speed squared and is greater in shallow water and for high block coefficient vessels.

Turning circle advance

The distance a vessel travels in the direction of her original course from the moment the helm is applied until she has turned 90 degrees; typically three to four ship lengths.

Overtaking definition

A vessel is overtaking when approaching another from more than 22.5 degrees abaft her beam; the overtaking vessel must keep out of the way until finally past and clear.

Crossing rule

When two power-driven vessels cross, the vessel with the other on her own starboard side keeps out of the way and should normally avoid crossing ahead of the other.

Restricted visibility rule

In restricted visibility, no vessel is stand-on; all proceed at safe speed, use radar and sound signals, and take avoiding action in ample time when risk of collision exists.

Safe speed factors

Safe speed depends on visibility, traffic density, manoeuvrability, stopping distance, background light, sea state, and the proximity of navigational hazards.

MARPOL Annex VI limits

Annex VI limits sulphur in fuel to 0.50% globally and 0.10% in Emission Control Areas; it also regulates NOx, ozone-depleting substances, and incinerator emissions.

STCW rest hours

Seafarers must have at least 10 hours of rest in any 24-hour period and 77 hours in any 7-day period; watch schedules must not impair fitness for duty.

UNCLOS maritime zones

Territorial sea extends 12 nautical miles, contiguous zone 24 nm, exclusive economic zone 200 nm, and the high seas beyond national jurisdiction.

ISM Code certificates

The company holds a Document of Compliance; each ship holds a Safety Management Certificate. Internal audits must be carried out within a 12-month period.

Draft survey accuracy

Draft survey displacement is corrected for trim, water density, and deductibles; the result is typically accurate to within about 0.5% of the calculated displacement.

Transportable moisture limit

The TML is the maximum moisture content at which a Group A bulk cargo is considered safe from liquefaction; cargo above the TML must not be loaded.

IMDG segregation codes

Segregation codes: 1 away from, 2 separated from, 3 separated by one compartment, 4 separated by two compartments, and X no general segregation required.

Grain heeling moment

The Grain Code requires calculation of heeling moments from grain shift and verification of residual stability and assumed heeling angle criteria before loading.

Oily water separator limit

Under MARPOL Annex I, an oily water separator must have a 15 ppm alarm and an automatic stopping device; discharges must be recorded in the Oil Record Book.

Steering gear changeover

SOLAS requires two independent power units; changeover from one to the other must be possible within 45 seconds, and emergency steering drills are held every three months.

BWM Convention standards

The Ballast Water Management Convention requires either D-1 exchange (95% volumetric or 200% flow-through) or the D-2 treatment standard for discharged ballast water.

GMDSS sea areas

A1 covers VHF DSC coverage, A2 MF DSC coverage, A3 Inmarsat coverage, and A4 the remaining sea areas where only HF provides distress communications.

Williamson turn

A man-overboard manoeuvre: put the helm hard over, then reverse it after 60 degrees, then steady on the reciprocal course to return to the person's position.

SMCP distress signal

Mayday is the distress signal, Pan Pan indicates urgency, and Securite indicates safety; Mayday is repeated three times followed by the vessel's name and position.

VHF channel 70

Channel 70 is reserved for Digital Selective Calling only; voice transmissions on Channel 70 are prohibited, and Ch 16 remains the distress and calling channel.