Grade 10 – Nautical Science

December 14, 2020

Commercial fishing vessels

There are a variety of fishing vessels which include trawlers, long-line craft, trap fishing craft, seiners, etc. Each has a different method of catching fish and is equipped accordingly. The seiner is a type of fishing vessel that uses sein nets to trap fish near the surface of the sea. […]
December 14, 2020

Tugs

Tugs are in effect marine tractors. Their purpose is to push/tow vessels when they cannot use their own engines or do not have any form of self propulsion. They are designed according to the environment in which they will operate, ie harbours, rivers or deep sea and according to their […]
December 14, 2020

Dredgers

Dredgers come in a variety of forms, types and sizes. Their purpose is to remove silt or sand from harbours, rivers or entrance channels to harbours, in order that seagoing vessels have sufficient depth to navigate safely in these confined spaces. They are also used in underwater mining operations. Whilst […]
December 14, 2020

Meteorology (weather at sea) – sources of meteorological information

Sources of meteorological information available to the mariner include the following: Maritime coastal radio stations (Walvis Bay, Luderitz, Cape Town, Port Elizabeth, East London, Durban). These provide storm warnings and weather forecasts. Cape Naval Radio (Silvermine, Cape Town). They provide facsimile weather maps and weather forecasts on behalf of the […]
December 14, 2020

Meteorological instruments

The met instruments usually carried aboard merchant vessels and warships are the following: Barometer. This instrument measures the atmospheric pressure (usually in millibars). They can either be mercury barometers or aneroid barometers. The first type uses a column of mercury to measure to measure the pressure, whilst the aneroid uses […]