Grade 11 – Nautical Science | Nautical Science Grade 11

October 22, 2020

Definitions

Highest Astronomical Tide (HAT) and Lowest Astronomical Tide (LAT). These levels are predicted to occur under average meteorological conditions and under any combination of astronomical conditions. They will not be reached every year. They are also not the extreme levels that can be reached, as storm surges and other meteorological […]

October 22, 2020

Use of the tide tables

The tide tables are used to determine the heights and times of high and low water at all the major ports in Namibia and South Africa. They are also used to determine the height of tide at anytime during the year at these ports. When using the tables certain parameters […]

October 22, 2020

Currents and tidal streams

Nature of currents. Currents are permanent or seasonal horizontal movement of water flowing in a certain direction and in the oceans caused by differences in temperature, salinity, density and wind. Information concerning their direction and strength is given on charts, in Sailing Directions and various current atlases. The net result […]

October 22, 2020

Definitions

The following terminology is used with currents and tidal streams: Set – we speak about the set of the current/tidal stream when referring to its direction of flow. It is expressed in degrees (°). Rate – this is the speed of the current/tidal stream expressed in knots. Drift – this […]