The technical processes of navigation are much the same in all craft, but there are certain requirements and problems which are peculiar to ocean racing. Compared with big ship navigation, the principal differences are:

(1) The ship's speed is irregular and is not always exactly known; it is also much lower so that the tidal streams and other sets play a much more important role.

(2) The course steered is often a constantly varying one, particularly when the vessel is on the wind, or before the wind.

(3) Leeway is a far larger factor.

(4) The violence of the motion and the lack of space greatly increase the difficulty of plotting and calculating.

(5) The methods of fixing the ship are generally less exact and less readily available.