(excerpt from Regulations about way of marking of waterways and aids to navigation)
The safe water mark has the shape of a sphere, pillar or spar, painted with vertical red and white stripes.
In cases where the safe water mark is in the shape of a pillar or spar, the topmark must be a red sphere.
The light of the safe water mark is a white isophase light, occulting or a white light with one long flash every 10 seconds or the Morse sign ''A'' (.-).
The safe water mark is used to mark:
- navigable water around the mark
- center line or the middle of the channel
- channel entrance or channel approach
- estuary, port or shore approach.
The safe water mark may replace the lateral (side) or cardinal (basic) mark to indicate the shore approach.
NAUTICAL CHARACTERISTICS OF SAFE WATER MARKS
| Safe water marks |
| Colour |
Red and white stripes |
| Shape |
Spherical, buoy with pillar or spar |
| Topmark |
Red sphere |
| Light (if any) |
White |
| Rhythm |
Isophase, occulting, L Fl every 10s or Morse ''A'' |