The emergency wreck mark: blue and yellow means new.

What is an emergency wreck mark?

A mark that can be used for a new danger. R1001 puts it simply: 'New dangers may be marked with an Emergency Wreck mark.' It is common to Region A and Region B.

What counts as a new danger?

A hazard that has only just been found, natural or man-made, which the charts and nautical publications may not show yet. R1001 treats it as a hazard until the competent authority is satisfied it has gone, or until word of it has been spread widely enough ('sufficiently promulgated').

Is a new danger always marked with an emergency wreck mark?

No. R1001 says new dangers should be marked with lateral, cardinal or isolated danger marks, or with an emergency wreck marking buoy. So a new wreck may be marked by, say, a cardinal; in practice, the emergency wreck mark is the one that announces itself as new.

What colour is an emergency wreck mark?

Blue and yellow vertical stripes, in equal number: a minimum of 4 stripes and a maximum of 8.

What shape is it, and what is the topmark?

A pillar or spar buoy. The topmark is a vertical/perpendicular yellow cross — an upright '+' — preferably three-dimensional so it can be seen from all directions.

A memory aid of ours: the emergency wreck mark's cross stands upright; the special mark's 'X' leans on its side.

What light does an emergency wreck mark show?

Alternating blue and yellow: one second of blue light and one second of yellow light, with a 0.5 second eclipse. Of the six types of mark, it is the only one to use blue.

Does it have a racon or AIS?

It may carry an AIS AtoN, and a racon showing Morse 'D' (dash dot dot).

When is a mark duplicated?

If the competent authority considers the risk to navigation especially high, at least one of the marks on a new danger should be duplicated. The duplicate must be identical to its partner in every respect.

What extra rules apply to a duplicate mark?

If a lighted lateral mark is used as the duplicate, it must show a very quick (VQ) or quick (Q) light. The new danger may also be marked by a racon coded Morse 'D' (dash dot dot), and by other electronic means such as an AIS AtoN.

How is it different from a special mark?

Both use yellow, but the emergency wreck mark adds blue: blue and yellow vertical stripes, an upright yellow cross and an alternating blue and yellow light. The special mark is plain yellow, with a diagonal yellow 'X' and a yellow light. One marks a new danger; the other a special area or feature you can look up on the chart.

What might they ask about the emergency wreck mark?

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

“Describe an emergency wreck marking buoy by day and at night.”

“At night you see a light alternating blue and yellow. What is it, and what does that tell you about your chart?”

“Which marks can be used for a new danger, and when is a mark duplicated?”

“What does a racon on a new danger show?”

The common slips: giving the special mark's 'X' as the topmark instead of an upright cross, and forgetting that a new danger can be marked with lateral, cardinal or isolated danger marks too.