October 11, 2020


This website has been compiled for the guidance of and use by grade 11 learners taking Nautical Science as one of their secondary school subjects. It follows the approved national curriculum for the subject and comprises four parts, namely Navigation, Seamanship, Meteorology and Communications. Although it has been written for […]
October 11, 2020

Introduction to sailings

‘Sailings’ is a term given to various methods used to determine courses and distances to be steamed when travelling from one geographical position to another. There are six different “sailings”, ie Parallel, Plane, Middle Latitude, Mercator, Great Circle and a combination of Great Circle and one of the others. During […]
October 15, 2020

Mercator sailings

Scale of a Mercator chart. Because the equator is shown on a Mercator chart as a straight line of definite length and the meridians appear as straight lines perpendicular to it, the longitude scale is fixed by that length and is constant in all latitudes. The latitude scale, on the […]
October 20, 2020

Astro navigation – the celestial sphere

Introduction. Astro-navigation is based upon the concept of the “celestial sphere”. What is the “celestial sphere”? If one looked up into the night sky one would see what would appear to be an enormous black dome with all the heavenly bodies stuck to the inside like thousands of diamonds. This […]