# Grade 11 – Nautical Science

October 22, 2020

## Plotting symbols

When plotting courses of vessels and the set of a current/tidal stream, the direction of travel is indicated by arrow heads pointing in the direction of travel. The number of arrow heads differentiate between courses steered, courses made good and the set of a current/tidal stream: One arrow head = […]
October 22, 2020

## Finding the set, rate and drift of a current

The best way of demonstrating how to find the set, rate and drift of a current is by using a practical example: Problem: From an observed position at 1200 a vessel steers 110° (T) at 12 knots. At 1330 another fix is obtained. Determine the set rate and drift of […]
October 22, 2020

## Finding the estimated position (EP) allowing for a current

The following example is used to explain the procedure to follow: Problem: From an observed position at 1200 a vessel steers 110° (T) at 10 knots. The current is setting 350° (T) at 2 knots. Determine the estimated position for 1330. Solution: Plot the true course from the 1200 position. […]
October 22, 2020

## Finding the course to steer in order to counteract the current

The following example is used to explain the procedure to follow: Problem: A vessel steaming at 10 knots wishes to make good a course of 110° (T) from its 1200 position. Find the course to steer allowing for a current setting 170° (T) at 2 knots. Solution: Plot the 1200 […]