Collision due to dragging anchor

28th October 2016

Collision due to dragging anchor

Initial Report

A vessel engaged in cargo operations with a barge, dragged anchor and collided with another vessel that was anchored astern.

What did the reporter tell us?

Vessel arrived and dropped anchor at Chittagong Roads for cargo operations. The master, after assessing one tidal change, allowed the engine room to commence de-pressurising the boiler for survey. The boiler economiser door was opened, the main engine jacket pump was stopped and the valves for the jacket water were closed. During the night the master relieved the 3rd Officer from anchor watch on the bridge as he was called to resolve a grab issue on deck.

The vessel started dragging anchor and this went un-noticed. There was an anchor watch alarm on the radar and this was acknowledged but not acted upon. Five minutes later the anchor watch alarm on the 2nd radar sounded and was acknowledged but again not acted upon. The master was preoccupied with the grab issues and at this time the vessel had a stern speed of 0.9 knots. Shortly thereafter, the 2nd and 3rd officers came on the bridge to discuss the grab issues with the Master and there was no effective anchor watch in place, as all were engrossed in the grab issue.

At 0027LT, the ship that was anchored right astern, called own vessel on VHF radio, which was not answered. Subsequently there were calls from a 3rd ship to another vessel and a blowing of the whistle. When the master heard the whistle he realised that his ship was dragging its anchor. By this time own vessel had a stern way of 1 knot and distance to the ship astern was 2 cables. The master asked the vessel astern to move away, as own ship was having engine problems, which was refused. The main engine was used to make headway, but did not get sufficient rpm. The port anchor was dropped to arrest the drag but this was unsuccessful, so the port anchor was picked up. Vessel continued to use the engine, though at lower rpm and commenced to pick up the starboard anchor with 7 shackles in the water. Once the starboard anchor was aweigh, the stern speed increased but the engine rpm could not be increased sufficiently to arrest the stern way, resulting in own vessel’s starboard life boat deck area coming into contact with the other vessel.

The lessons to be learnt

Reporter’s suggestions to prevent similar incidents

Proper anchor watch must be maintained at all times, whilst vessel is at anchorage.

Main engine shall be kept on immediate readiness in crowded anchorages, or in anchorages where dragging is possible due to the nature of the bottom, the current, topography, etc.

If there is a need to immobilise the engines, a thorough risk assessment must be carried out, giving due consideration to prevailing circumstances and ships in the vicinity.

CHIRP Suggests

CHIRP noted the report showed a poor level of seamanship, the cumulative risk of the distraction due to the cargo operations in a high-risk anchorage area, the lack of response to two alarms and non-compliance with company guidelines.  The delay in starting the main engine, as it was not warmed through, should have been overridden by the higher risk of damage to the hull and for preserving safety of life.

CHIRP also questioned, why the company agreed to engine immobilisation in such a high-risk anchorage?

See Notice to Mariners advice on anchorage at the Port of Chittagong, whereby the ship’s engines are to be kept on standby at all times. http://cpa.gov.bd/instruction-to-mariners/

See also GARD P&I Club advice: http://www.gard.no/Content/20724691/Gard%20Alert_Chittagong.pdf

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