Jul 182009

Safe at anchor? Not! Photo: London P&I Club Stoploss Bulletin

Anchoring and anchored ships seem to have a disturbing habit of bumping into each other, especially in places where there are strong currents or tidal flows, warns the London P&I Club’s latest Stoploss bulletin. With so many ships laid-up in various harbours around the world, it’s a problem that’s likely to be with us for a while.

Yet many of the incidents reviewed by the Club precede the recent market difficulties which have led to a significant increase in the number of ships at anchor off busy ports.

Says the club: “A typical case involves a ship manoeuvring at slow speed which is
set down upon an anchored vessel. Often a collision occurs when a ship is in
the process of dropping anchor.”

According to the club’s analysis the bridge team on the moving ship often appear to have been fully aware of a strong cross-current but failed to appreciate that a steady current would have a greater impact upon the ship’s track as its speed reduced.

All other things being equal, the slower a vessel moves the less manoeuvrable she’s going to be and the more impact a steady current or tidal flow will have. Possibly something easy to overlook after a long voyage in the hustle of putting down the hook.

“Moreover,” says the club, “opportunities to monitor cross-track error by parallel indexes were often missed.“

Given the frequency with which a lack of parallel indexing appears in maritime incident reports MAC is not surprised. Whether today’s seafarers don’t know how to use it, can’t be bothered to use it, or simply don’t know how and when it should be used is something worth looking at.

Other incidents involve contact after a ship drags its anchor. In some cases, says the club, the bridge team misjudged how little time would be available to arrest
the ship’s movement if the anchor dragged given the close proximity of other anchored ships.

“Occasionally, the risk of collision was increased by a failure to monitor the ship’s position carefully. In more than one case, the colliding ship appears to have realised
that it was dragging towards another ship only when that ship made VHF contact. Again, the radar could have provided early warning of the danger had an appropriate guard ring been set up.”

Sometime the first intimation that your ship is dragging its anchor is when every other ship in the anchorage is moving in one direction, a rather disturbing experience, and by then it may be too late to take effective action.

Drop the hook, set up guard ring. Seems simple enough.

Warns the club: “The greater risk associated with increased congestion reinforces the need for bridge teams to follow best practice in passage planning and watch-keeping.”


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