SAMSA Skipper Category C (Coastal, up to 15 nm) Exam (South Africa) cheat sheet

Latitude is measured 0°–90° N or S of the equator; longitude 0°–180° E or W of the Greenwich meridian.

1 minute of latitude = 1 nautical mile; 1 minute of longitude = 1 nm × cos(latitude).

Speed–time–distance: Distance (nm) = Speed (kn) × Time (h); Time = Distance ÷ Speed; Speed = Distance ÷ Time.

Dead reckoning position = last fix advanced by course steered and speed through the water, corrected for known current and leeway.

True bearing = Magnetic bearing + Variation (east add, west subtract); Magnetic bearing = Compass bearing + Deviation (east add, west subtract).

A fix requires two or more position lines (bearings, ranges, or ranges plus bearing) crossing at a good angle, ideally near 90°.

On a Mercator chart the scale varies with latitude and should be read from the latitude scale at the vessel's own latitude.

A running fix advances an earlier position line by the vessel's run between observations.

Spring tides occur near new and full moon (aligned Sun and Moon forces) giving the greatest tidal range; neap tides occur near the quarter moons.

Rule of twelfths over a 6-hour rise or fall: 1/12, 2/12, 3/12, 3/12, 2/12, 1/12 of the range per hour.

Height of tide at any time = charted height above chart datum + height of tide above datum.

Chart datum is normally close to Lowest Astronomical Tide, so most charted depths are minimum expected depths.

The tidal stream direction and rate change through the cycle and are read from tidal diamond or tidal stream atlas data for the relevant hour.

Set is the direction toward which a current flows; drift is the speed of that current.

A vessel's course to steer must offset the tidal stream: course steered = course made good corrected for set and drift.

Duration of flood plus duration of ebb between successive high and low waters is typically about 12 hours 25 minutes.

A falling barometer indicates approaching low pressure and generally deteriorating weather; a rapid fall warns of strong winds.

In the southern hemisphere winds circulate clockwise around a low and anticlockwise around a high.

Buys Ballot's law (southern hemisphere): with your back to the wind, low pressure lies to your left.

Sea breeze blows from sea to land by day; land breeze blows from land to sea at night.

Fog forms when air is cooled to its dew point; warm moist air over a cold sea surface produces advection fog.

A cold front passage brings a wind shift, often to the south-west in South African waters, with squalls and rain.

The Agulhas Current flows south-west along the east coast of South Africa and can raise steep short seas against a north-east wind.

Beaufort force is estimated from sea state; force 6 (strong breeze) shows large waves with white foam crests and some spray.

Power-driven vessel under way: masthead light(s), sidelights (red port, green starboard) and a sternlight.

A power-driven vessel of less than 12 m may show an all-round white light and sidelights instead of masthead and stern lights.

Sailing vessel under way: sidelights and sternlight; a vessel under oars may carry a torch or lantern showing a white light in time to prevent collision.

Vessel at anchor by day shows a black ball forward; at night shows an all-round white light where best seen.

Vessel not under command shows two all-round red lights in a vertical line at night and two black balls by day.

A vessel constrained by her draught shows three all-round red lights in a vertical line at night and a cylinder by day.

One short blast means 'I am altering my course to starboard'; two short blasts 'to port'; three short blasts 'I am operating astern propulsion'.

In a crossing situation the vessel with the other on her starboard side is the give-way vessel and must keep clear.

IALA Region A applies in South Africa: red can buoys mark the port side of the channel when entering from seaward; green conical buoys mark starboard.

Cardinal marks indicate the safe side to pass: north (two cones up), east (cones base-to-base), south (two cones down), west (cones point-to-point).

Safe water marks show red and white vertical stripes with a single red sphere topmark.

Special marks are yellow and mark features such as spoil grounds, pipelines or swimming areas.

Isolated danger marks are black with a red band and two black spheres, placed on a danger with safe water around it.

A light's characteristic is given as colour, period and phase, e.g. Fl(2)R 10s means a red group of two flashes every 10 seconds.

A sector light shows different colours over defined arcs; the white sector normally indicates the safe approach.

Chart symbols: a wreck with a dotted outline and sounding inside is a dangerous wreck; crosses indicate rocks awash.

A bowline forms a fixed loop that will not slip and is used for securing a line around a post or to a person.

A round turn and two half hitches secures a line to a post or ring and can be eased under load.

A cleat hitch is made with a full turn around the base, then figure-of-eight turns and a locking turn.

Anchor scope: use about 5–7 times the depth of water in chain, or more in strong wind or heavy swell.

Anchor bearing and transit should be checked to confirm the anchor is not dragging.

When turning a vessel with a right-hand propeller, astern power tends to walk the stern to port.

Spring lines prevent fore-and-aft movement alongside; breast lines hold the vessel close to the berth.

A vessel approaching a berth should arrive with the tide and wind considered, usually heading into the stronger of the two.

MAYDAY is the distress signal for grave and imminent danger requiring immediate assistance, sent on VHF channel 16.

PAN PAN is the urgency signal for urgent but non-immediate danger; SECURITE announces safety information.

DSC distress alert is sent on VHF channel 70 followed by voice on channel 16.

A MAYDAY call states: MAYDAY repeated, vessel name and callsign, position, nature of distress, assistance required and persons on board.

Man-overboard drill: shout, throw a lifebuoy, keep the casualty in sight, press MOB on GPS and approach into wind and sea.

Lifejackets should be fitted with a whistle and light; inflatable types must be regularly checked and the cylinder in date.

A flare should be fired downwind and at an angle; red hand flares and parachute flares are distress signals.

EPIRB 406 MHz and SART are carried for distress alerting and radar location; the EPIRB should float free and be registered.

SAMSA administers the Merchant Shipping Act and the Small Vessel Regulations for recreational and small commercial vessels.

A Category C skipper certificate permits coastal operation up to 15 nautical miles from shore in South African waters.

The skipper is responsible for the safety of the vessel and all persons on board and must ensure the vessel is seaworthy and correctly equipped.

Required safety equipment depends on vessel category and area of operation and includes lifejackets for all persons on board, a fire extinguisher, and a first-aid kit.

A vessel must be registered and carry a valid certificate of competency and, where required, a local general safety certificate.

Reporting of accidents and casualties to SAMSA is mandatory; pollution of the sea by oil or garbage is prohibited under MARPOL.

The skipper must render assistance to persons in danger at sea without serious danger to the own vessel and persons on board.

Alcohol and drugs impairing safe operation are prohibited; the skipper must ensure the vessel is not operated by an impaired person.

Centre of gravity above the centre of buoyancy gives positive stability; the metacentric height (GM) is a measure of initial stability.

Free surface effect from slack tanks or loose water reduces stability; keep tanks pressed full or empty.

Weight stowed high raises the centre of gravity and reduces stability; heavy items should be stowed low and secured.

A vessel is stiff if GM is large (rapid, jerky roll) and tender if GM is small (slow, easy roll).

Bilge water must be kept pumped out; a build-up of bilge water reduces stability and indicates a leak.

A 12 V battery is charged by the engine alternator; a battery isolator switch disconnects the battery when the vessel is unattended.

Fuses and circuit breakers protect circuits; a fuse must be replaced with one of the correct rating.

An inboard petrol engine requires a blower to clear the engine space of fuel vapour before starting.

Latitude is measured 0°–90° N or S of the equator; longitude 0°–180° E or W of Greenwich.

1 minute of latitude equals 1 nautical mile.

Distance (nm) = Speed (kn) × Time (h).

True bearing = Magnetic bearing + Variation (east add, west subtract).

A fix needs two or more position lines crossing at a good angle.

Read chart scale from the latitude scale at the vessel's latitude on a Mercator chart.

Spring tides near new and full moon give the greatest range.

Rule of twelfths: 1,2,3,3,2,1 twelfths of the range per hour over six hours.

Chart datum is near Lowest Astronomical Tide, so charted depths are minimum expected depths.

Set is the direction toward which a current flows; drift is its speed.

Tidal stream data give direction and rate for the relevant hour of the tide.

Course to steer must offset the tidal set and drift.

Falling barometer indicates approaching low pressure and deteriorating weather.

In the southern hemisphere winds circulate clockwise around a low.

Buys Ballot (southern hemisphere): back to wind, low pressure is to your left.

Sea breeze blows sea to land by day; land breeze land to sea at night.

The Agulhas Current flows south-west along the east coast and steepens seas against a north-east wind.

A cold front passage brings a wind shift, squalls and rain.

Power-driven vessel under way shows masthead light(s), sidelights and sternlight.

Sailing vessel under way shows sidelights and sternlight.

Vessel at anchor shows a black ball by day and an all-round white light at night.

Not under command shows two all-round red lights vertically and two black balls by day.

One short blast = altering to starboard; two short = to port; three short = operating astern.

In crossing, the vessel with the other on her starboard side gives way.

IALA Region A: red can buoys mark port side of channel when entering from seaward; green conical mark starboard.

Cardinal marks: north two cones up, east base-to-base, south two cones down, west point-to-point.

Safe water marks are red and white vertical stripes with a red sphere topmark.

Special marks are yellow and mark spoil grounds, pipelines or swimming areas.

Isolated danger marks are black with a red band and two black spheres.

Fl(2)R 10s means a red group of two flashes every 10 seconds.

A bowline forms a fixed loop that will not slip.

A round turn and two half hitches secures a line to a post or ring.

Anchor scope is about 5–7 times the depth of water in chain.

Check anchor bearing and transits to confirm the anchor is not dragging.

Astern power with a right-hand propeller tends to walk the stern to port.

Spring lines prevent fore-and-aft movement alongside.

MAYDAY is the distress signal for grave and imminent danger, sent on VHF channel 16.

PAN PAN is the urgency signal; SECURITE announces safety information.

DSC distress alert is sent on VHF channel 70 followed by voice on channel 16.

MAYDAY call states vessel name, position, nature of distress, assistance required and persons on board.

Man-overboard: shout, throw a lifebuoy, keep the casualty in sight and approach into wind and sea.

EPIRB 406 MHz and SART aid distress alerting and radar location.

SAMSA administers the Merchant Shipping Act and Small Vessel Regulations.

A Category C skipper certificate permits coastal operation up to 15 nautical miles from shore.

The skipper is responsible for the safety of the vessel and all persons on board.

Required safety equipment depends on vessel category and area of operation.

Accidents must be reported to SAMSA; oil and garbage pollution is prohibited under MARPOL.

The skipper must render assistance to persons in danger at sea where safe to do so.

Metacentric height (GM) is a measure of initial stability.

Free surface effect from slack tanks reduces stability; keep tanks pressed full or empty.

Heavy items should be stowed low and secured to keep the centre of gravity low.

A stiff vessel has a large GM and rolls rapidly; a tender vessel has a small GM.

A battery isolator switch disconnects the battery when the vessel is unattended.

A fuse must be replaced with one of the correct rating.