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

A confirmed location of the vessel obtained by crossing two or more position lines or by electronic means, plotted on the chart at the time of observation.

A line drawn on a chart along which the vessel must lie, derived from a single observation such as a bearing, range or sounding.

The vessel's estimated position calculated from the last known fix by applying course steered and distance run through the water, without allowing for current or leeway.

The best guess of the vessel's location, found by adjusting the dead reckoning position for the effects of current, tidal stream and leeway.

Two charted objects seen in line, giving a single position line that is highly accurate when the objects are well separated and clearly identifiable.

The direction of an object from the vessel, measured in degrees clockwise from north, either true or relative depending on the reference used.

The reference level on a nautical chart from which depths and drying heights are measured, usually close to the lowest astronomical tide in South African waters.

The depth of water printed on a chart, measured below chart datum and shown in metres and decimals, not the actual depth at any given moment.

A regular official publication that advises mariners of changes to charts, lights, buoys, hazards and navigational information affecting safe passage.

The manual or digital updating of a nautical chart using information from Notices to Mariners so that it reflects current conditions.

Official books describing coastal waters, harbours, anchorages and local hazards, used with charts to plan passages and approaches.

A written plan for a voyage setting out the intended track, waypoints, courses, distances, tidal and weather considerations, hazards and contingency anchorages.

A chosen position, usually expressed as latitude and longitude, that marks a point on the intended track or a turning point along the route.

The predicted height of the tide above chart datum at a given place and time, taken from tide tables for the standard or secondary port.

The large tidal range that occurs near new and full moon, when the sun and moon pull in line and high waters are higher and low waters lower than average.

The small tidal range that occurs near the first and third quarters of the moon, when solar and lunar forces partly oppose each other.

The direction in which a current or tidal stream flows (set) and the speed at which it flows (drift), used to calculate the course to steer.

The compass course the helm must hold so that, after allowing for current, tidal stream, leeway and compass error, the vessel tracks the intended ground course.

The sideways drift of a vessel downwind of its heading, caused by wind pushing on the hull and superstructure, which must be allowed for when steering.

A numbered scale from 0 to 12 describing wind strength by its observable effects on sea state, used in weather reports and forecasts.

An instrument that measures atmospheric pressure; a falling reading usually warns of approaching bad weather while a rising reading suggests improving conditions.

The vertical distance between the lowest point of the vessel's hull and the seabed, calculated from charted depth plus tidal height less the vessel's draught.

The vertical distance from the waterline to the lowest point of the vessel's hull, which determines the minimum depth of water needed to float safely.

The buoyage system used in South Africa and most of the world, where red buoys mark the port side of a channel when entering from seaward and green marks starboard.

A buoy or beacon indicating the sides of a navigable channel; in Region A, red can-shaped marks are port hand and green conical marks are starboard hand.

A buoy or beacon whose black and yellow colouring and topmark indicate the direction of safe water, named north, east, south or west according to the compass.

A red and white vertically striped buoy or beacon with a red sphere topmark, marking the centre of a channel or a landfall where navigable water lies all around.

A black and red horizontally banded buoy with two black spheres as topmark, placed on or near a small isolated hazard with safe water around it.

A yellow buoy or beacon, often with a yellow cross topmark, marking special areas such as spoil grounds, pipelines, racing marks or administrative zones rather than a navigational channel.

In a crossing situation the vessel that must keep out of the way of the other, normally the one that has the other on her starboard side.

The vessel that is required to keep her course and speed in a crossing or overtaking situation, while the give-way vessel takes avoiding action.

The collision regulations that set out steering, sailing and lighting rules so that vessels know who must give way and what action to take to avoid collision.

The error in a magnetic compass caused by magnetic influences on board the vessel, which varies with the vessel's heading and must be applied to convert compass to magnetic.

The angular difference between true north and magnetic north at a given place, shown on the chart and changing slowly over the years.

The international distress, safety and calling frequency used for initial contact and emergencies, over which Mayday and Pan Pan calls are made.

Digital Selective Calling, a VHF and MF function that sends an automated distress alert with the vessel's identity and position at the press of a button.

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

The urgency signal used when a vessel or person is in difficulty but not in immediate danger, requesting assistance or advising other vessels.

An Emergency Position Indicating Radio Beacon that, when activated in the water, transmits a distress alert with the vessel's identity to rescue authorities via satellite.

An inflatable craft carried on board for abandoning ship, stowed in a container that is launched and inflated when the vessel must be left.

The last-resort order to leave a sinking or burning vessel, after which the crew take to the life raft or rescue craft with distress signals and water.

A person who has fallen into the water, requiring immediate action: shout, throw a float, keep the person in sight and manoeuvre the vessel back for recovery.

The official document issued to a person who has passed the required examination and met the sea service requirements for a given grade of skipper.

The colloquial South African name for the certificate of competence held by a skipper, such as the Category B ticket valid for coastal passages up to 40 nautical miles.

A document issued for a vessel stating the minimum number and qualifications of crew required to operate her safely.

The International Regulations for Preventing Collisions at Sea, covering conduct of vessels, lights, shapes and sound signals in all waters.

A description of the condition of the sea surface, usually by wave height and character, as reported in forecasts and observed from the vessel.