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Parting of hawser and bulk cargo hose during tandem mooring

What happened

During at-sea bunkering operations between two vessels, a mooring line parted and then a fuel hose parted also. There was no spillage of fuel. The incident occurred when one vessel (Vessel A) arrived to deliver fuel to another vessel (Vessel B), which was at anchor with thrusters running.

It was decided to moor both vessels in tandem. Vessel B would maintain heading and control yaw using thrusters. Both vessels were moored to each other using one rope in a criss-cross fashion.

Vessel B could not start its fuel pump and thus the fuel transfer could not be started. The two vessels stayed connected in tandem.

The mooring rope from Vessel A parted due to jerking and continuous yawing. Crew on Vessel B were told to close the deck fuel valve and disconnect the hose for retrieval. The hose was disconnected and crew on Vessel A started retrieval using the port tugger winch. While they were retrieving the hose, it got entangled with the remaining single mooring rope and the vessel structure, and the hose parted on deck. No spillage was noticed as hose was empty.

The parted mooring rope and bulk cargo hose were retrieved by Vessel A.

What went wrong/causes

  • There were 1.5m seas and wind of approx. 14 knots. Both vessels were yawing – the mooring ropes was getting intermittent jerks which resulted in one of them parting. The uncontrolled heaving of the bulk cargo hose resulted in it parting;
  • Both vessels could have decided to call off or postpone the operation until the fuel pump was operational and/or weather would improve.

Members may wish to review the following incident:

Safety Event

Published: 25 July 2017
Download: IMCA SF 18/17

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