The safe water mark: navigable water all round, no danger.

What does a safe water mark mean?

That there is navigable water all around the mark. R1001 is explicit that it 'does not mark a danger'. It is common to Region A and Region B.

Where are safe water marks used?

R1001's examples: as a fairway, mid-channel or landfall mark, and as a centre-line mark. It may also show a channel entrance, the approach to a port or estuary, or the best point of passage under a bridge.

Which side do I pass a safe water mark?

R1001 doesn't name a side: the water is navigable all round the mark. As we read it, the choice then comes from the chart, the channel and the steering and sailing rules, not from the mark.

What colour is a safe water mark?

Red and white vertical stripes. R1001 notes that safe water marks are made to look different from the buoys that mark dangers.

What shape is a safe water buoy?

Spherical; or a pillar or spar with a spherical topmark.

What is the topmark?

A single red sphere. Where weather or ice make a topmark impractical, the authority may decide not to fit one.

What light does a safe water mark show?

If one is fitted: white, with one of four rhythms — isophase, occulting, one long flash every 10 s, or Morse 'A' (dot dash). It may also carry an AIS AtoN or a racon.

R1001 defines a long flash, in its section on cardinal marks, as a light appearance of not less than 2 seconds.

How do I tell a safe water mark from an isolated danger mark?

Both have navigable water all round, but only the isolated danger mark has a danger at it. By day: the safe water mark has red and white vertical stripes and one red sphere; the isolated danger mark is black with red horizontal bands and two black spheres. At night both lights are white, but the isolated danger mark shows group flashing (2), which is none of the safe water rhythms.

How do I tell its light from a cardinal?

Cardinal lights are very quick (120 or 100 flashes a minute) or quick (60 or 50 a minute) flashing, and R1001 says the safe water rhythm can't be confused with a cardinal's. The one to think about is the long flash: the south cardinal ends its group with one, but only after six very quick or quick flashes.

Can a safe water mark mark a new danger?

No. In R1001's table of how each type of mark can be applied, the safe water mark is not one of the marks for new dangers — those are lateral, cardinal, isolated danger and emergency wreck marks. That fits its meaning: it marks no danger.

What might they ask about the safe water mark?

Examples of the kind of question to be ready for (our wording, not the MCA's):

“Describe a safe water mark by day and at night.”

“What light rhythms can a safe water mark show?”

“Making a landfall at night, you see a white light showing Morse 'A'. What is it telling you?”

“Name a mark with water all round it that is not a safe water mark, and tell them apart.”

The common slips: forgetting that the stripes are vertical, and giving only one of the four light rhythms.