Buoyage and Lights

New Dangers

A new danger is a newly discovered hazard to navigation that is not yet indicated on charts or Sailing Directions and has not been sufficiently published in Notices to Mariners. This situation arises with newly discovered natural dangers such as rocks or banks but is mainly used to mark recent wrecks.

Buoys in use

A Lateral or Cardinal mark may be used, if appropriate there may be more than one, for example by port and starboard lateral buoys marking either side of the hazard.

If the danger is particularly serious, at least one of the buoys may be duplicated. That is, two identical buoys will be sited close together to emphasis the danger.


The light will be quick or very quick in sequence. Red or green for a lateral mark and white for a cardinal buoy.


A racon may be fitted to one of the buoys. In this case it will display the letter "D" (dash dot dot) giving a signal length of 1 mile.

New danger marked by lateral buoys and racon.

Prior to a cruise to north Brittany I corrected the charts for the area but when I arrived off the entrance to L'Aber Wrac'h there were two north cardinal buoys where I was expecting to see only one. As there were no other vessels around I was not sure how to enter the harbour as I thought there was a possibility that there was some new danger in the approach to the channel.

We kept well clear of the area marked by the buoys and made our way in safely, later in the day I looked in the Harbour Master's office at the local notices to mariners and there was a warning that there would be an experimental buoy placed next to the normal north cardinal.

So no matter how well prepared you think you are, always be ready for the unexpected.

Experimental New Danger BuoysNew Danger Buoy.

Trinity House are experimenting with a new type of buoy that has been recommended by IALA for marking new wrecks. This has come about due to the collisions which occurred in the Dover Straits in 2002 when vessels struck the new wreck of the Tricolour.

The new buoys will be blue and yellow vertical stripes with an alternating blue and yellow occulting light.


A pillar of spar buoy, the size dependent upon the situation.


Between 4 and 8 vertical blue and yellow stripes, these stripes will be of New wreck buoy.equal width. The abbreviation of the colour will be BuY.


An alternating blue and yellow flashing light with a nominal range of 4 nautical miles, the blue and yellow 1 second flashes are alternated with an interval of 0.5 seconds. Bu1.0s+0.5s+Y1.0s+0.5s= 3.0s


The top mark, if fitted, is to be a standing/upright yellow cross. (This shape is new for the IALA Buoyage System.)

These buoys will remain on station until:

• The wreck is well known and has been promulgated in nautical publications;
• The wreck has been fully surveyed and exact details such as position and least depth
above the wreck are known;
• A permanent form of marking of the wreck has been carried out.

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