SAMSA Skipper Category B (Coastal, up to 40 nm) Exam (South Africa) flashcards

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

One minute of latitude

Equals one nautical mile (1852 metres) and is used to measure distance on the chart's latitude scale, not the longitude scale.

Running fix

A position obtained by advancing an earlier position line by the vessel's course and distance run over the elapsed time, then intersecting it with a new line.

Dead reckoning position

A position derived from course steered and speed through the water, without allowing for leeway or current, so it is only an estimate.

Compass error formula

Compass error equals magnetic variation plus deviation; true bearing equals compass bearing plus easterly error or minus westerly error.

Chart datum

The reference level to which charted depths and drying heights are related; soundings show depth below this level.

Notices to Mariners

Official publications that amend charts and nautical publications; a chart is current only when the latest affecting notices have been applied.

Under-keel clearance

Charted depth plus height of tide minus vessel draught, with allowance for squat, swell and chart inaccuracies.

List of Lights

A publication giving light characteristics, ranges and heights of lights, used to identify marks and aids to navigation at night.

Rule of twelfths

In a six-hour tide the rise or fall is 1/12, 2/12, 3/12, 3/12, 2/12 and 1/12 of the range in each successive hour.

Spring tides

Tides of greatest range occurring near new and full moon when solar and lunar tidal forces align.

Buys Ballot's law

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

Sea breeze

A daytime wind blowing from sea to land, caused by the land heating faster than the sea surface.

Beaufort force 8

A gale with wind speeds of 34 to 40 knots, producing high waves with crests breaking into spindrift.

Overtaking rule

Any vessel overtaking another must keep out of the way until finally past and clear, regardless of vessel type.

Head-on rule

When two power-driven vessels meet head-on, both alter course to starboard and pass port-to-port.

Crossing rule

A power-driven vessel with another on her starboard side is the give-way vessel and must keep out of the way.

IALA Region A

The buoyage system used in South Africa: port-hand marks are red and can-shaped, starboard-hand marks are green and conical.

Cardinal marks

Marks indicating the safe side to pass, identified by cone topmarks: north two up, east base-to-base, south two down, west point-to-point.

Pivot point

The point about which a vessel turns, roughly one-third to one-quarter of the length from the bow when moving ahead.

Transverse thrust

The sideways force from a right-handed propeller: in ahead gear it tends to walk the stern to starboard, in astern gear to port.

Anchoring scope

The length of cable or rope veered, typically about five to seven times the depth in good holding ground.

Spring lines

Mooring lines led fore and aft to prevent the vessel surging along the berth while head and stern lines control fore-and-aft movement.

Squat

A reduction in under-keel clearance caused by water flow around a moving hull, increasing with speed and in shallow water.

MAYDAY signal

The distress signal spoken three times, used only when a vessel or person is in grave and imminent danger and immediate assistance is required.

PAN-PAN signal

The urgency signal spoken three times, used for a serious situation that is not yet a distress situation but requires attention.

DSC distress alert

A digital distress alert sent on VHF channel 70 containing the vessel's MMSI, followed by a voice MAYDAY on channel 16.

EPIRB

An emergency position-indicating radio beacon transmitting on 406 MHz to the COSPAS-SARSAT satellite system, and registered with the national authority.

Skipper Category B

A South African certificate of competency allowing coastal operation up to 40 nautical miles from the coastline, subject to the vessel's certificate.

SAMSA

The South African Maritime Safety Authority, which administers the Merchant Shipping Act and issues skipper certificates of competency.

MARPOL

The international convention regulating pollution from ships, prohibiting discharge of oil, garbage and sewage except as permitted.

VHF channel 16

The international distress, safety and calling channel; channel 70 is reserved for DSC and must not carry voice traffic.

MMSI

A unique nine-digit identifier programmed into DSC and AIS equipment to identify the vessel in digital transmissions.