Grade 12 – Nautical Science | Nautical Science Grade 12

September 17, 2020

Blind pilotage techniques

Radar really comes into its own during poor visibility. The techniques that will be described in this section applies to such circumstances. Whilst most modern marine radars now have a computer built in (ARPA – Automatic Radar Plotting Aid), which provides many more features than the older sets, the basic […]

September 17, 2020

Radar plotting

Why do we need to do radar plotting? The International Regulations for the Prevention of Collisions at Sea (1972) as amended (Colregs) requires the systematic observations of targets. Extracts from Rule 7 b. and c. state: Rule 7b. “Proper use shall be made of radar equipment if fitted and operational, […]

September 20, 2020

Electronic navigation systems

Introduction. On modern sea-going vessels there are a number of electronic navigation systems and equipment which are designed to assist the navigator to navigate his vessel safely. They are: The gyro compass. Ship’s log. Echo sounder (depth recorder). Radar. Automatic radar plotting assistant (ARPA). Automatic identification system (AIS). Global positioning […]

September 20, 2020

Gyro compass

Except for small recreational vessels, most vessels are equipped with two types of compass, namely a gyro and a magnetic compass. The former is used as the primary compass with the latter as back-up in the event of gyro or power failure. Since the latter makes use of the earth’s […]

September 20, 2020

Ship’s log

The ship’s log is basically the “speedometer and odometer” of a vessel. And performs exactly the same function as that of a motor car, i.e. it records the speed of the vessel and the distance travelled. Initially logs were purely mechanical and required no electrical power to operate. They only […]