Navigation and Seamanship

4.3.5.4. Safe water marks

Safe water marks are placed to indicate that there is navigable water all round their position like mid – channel marks (but it does not mark a danger or hazard). Spherical or alternatively pillar or spar with a single red spherical top mark. They are the only type of mark to have vertical strips (red and white).

Lights – isophase, occulting, one long flash or morse A rhythms. When the light is installed, then its colour is white and its rhythm may be isophase, occulting, long flash or the Morse Code letter "A".

Safe water mark

Meaning: t he water all around is free from obstruction of shallows.

Colour: red with white vertical stripes.

Top mark: single red sphere.

Light: single white long flash every ten seconds, isophase or occulting.