Apr 082008

MAIB’s latest Safety Digest includes the expected eyebrow/hair raisers and tragedies ranging from “How the whatsit…?” to “There but for the grace of God…”, three of which caught MAC’s quirky eye.

First there’s the crewman aboard a tug whose left ankle was caught by a heaving line that proceeded to pull him towards the panama eye. As the trapped crewman brace himself against the panama eye and other crewmen tried to free the line, and the officer in charge took a couple of steps to grab a knife from the galley, the trapped crewman decided he didn’t want to lose his leg, brought his feet together and let himself be pulled through the eye.

He fell into the water, got free of the line and swam to surface, where he was brought aboard the tug. He walked ashore for a medical examination, having sustained the loss of the tip of a little finger and bruising to his leg.

The tug isn’t named in the Safety Digest but the full report, involving the containership Velasquez and the tug Smit Collingwood can be read here.

Lessons? Among others, keep a means handy to cut through lines in an emergency, and maybe take another look at that New Year’s resolution about diets.

Another case involved the grounding of a jack-up barge being pulled by a tug, causing quite a lot of damage to the legs of the barge. The charted depth was greater than 20 metres, going down to 26 metres in the area of the grounding and the barge legs had been dropped to just 13m for stability.

In fact there was an uncharted bank with as minimum depth of less than 8 metres.

The last time the area had been charted was in the mid-19th century, with leadlines, not a very high-resolution technique.

With larger vessel with deeper drafts routing through more remote areas more often this is something we’re likely to see happening again. Its a good idea to take a look at the source diagram on paper charts in less well-travelled areas, if the survey was 18-something-or-other it will had been done by leadline and may well have hidden surprises.

If using ECDIS, take a look at the Category Zone of Confidence, CATZOC. However Electronic Chart Displays and chart plotters might not display CATZOC, so it might be wise, against, to check the paper chart.

It’s wise to use echo sounders (fathomometers in US-speak) in less well surveyed areas even if shallows aren’t expected.

Finally, in this fun-filled threesome, is the case of a small commercial vessel that didn’t do its passage planning very well.

Approaching a narrow entrance to a small inlet the skipper saw two small marker buoys close ahead, went to port to avoid them and grounded on the rock ledge that the buoys had been set out to mark. Oops.

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