Dive to Clear a Fouled Propeller ???

31st January 2011

Dive to Clear a Fouled Propeller ???

Initial Report

Report Text:

Whilst on passage in the Dover Straits, the wind had dropped completely so we were motoring at 5-6 knots. As we started to cross the North bound TSS lane, the propeller fouled and our speed though the water was reduced to 3-4 knots. Three ships had to be avoided crossing to South Foreland /South Goodwin buoy with difficulty.

We arrived off Dover East entrance, at the second hour of flood tide in dark at 2330hrs.  We were trying to make the West entrance to avoid ferry traffic. We were In touch with Dover Port Control.  We were soon making only making 1 knot, trying to get to back eddy from “knuckle” on harbour wall.  No progress.  A ferry avoided us by 200m. Thereafter we were towed in by a Harbour launch.

Next day I dived and removed 1-1.5m of 80mm square mesh green trawl net from the propeller. Fortunately,   no damage was done to the propeller or shaft.

Lessons Learned:

  1. Always have face mask on board to be able to dive and clear fouled propeller. (The weather was calm so we could not sail to safety)
  2. Patent “rope cutters” do not clear net debris!

CHIRP Comment:

We can envisage that being immobilised close to Dover Harbour entrance would have caused considerable anxiety and were pleased to read that a Harbour launch was able to provide assistance.

We would make the following comments regarding the report and the lessons learned as described by the yachtsman:

If immobilised, an advisory call to the Coast Guard, as well as to Port Control, may be prudent.

If the yacht is being swept towards a hazardous area, prepare the anchor for letting go, perhaps attaching extra warps if additional length of anchor line is needed.

Rope cutters do vary in their effectiveness. Reports of comparative tests can be found on the internet.

With reference to the yachtsman’s conclusion that a face mask should always be carried, we would advise that proper consideration should be given to the risks of diving to clear a propeller before undertaking this. Particular consideration should be given to:

–    the swimming and diving ability of the person intending to dive;

–    sea conditions;

–    water temperature;

–    the possibility of the diver cutting himself/herself;

–    availability of protective equipment (e.g. face mask, wet suit);

–    means of re-boarding the yacht ;

–    potential support to the diver from others on board if anything goes wrong.

If outside assistance is available, the safest option may well be to take it, as the yachtsman did in this incident.

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