At its latest safety digest, UK MAIB describes an incident involving a laden bulk carrier and a tug. Namely, as the bulk carrier was approaching the lock entrance, and when the tug put weight on the line, it parted. The bulk carrier contacted a pier, sustaining damages to its port side.
The incident
A laden bulk carrier with a pilot onboard was entering a port in the early hours of morning. As two harbour tugs were assisting in, the ship was proceeding at slow speed towards an open lock gate.
One tug was standing by on the starboard side, helping the ship to align as it prepared to enter the lock. The second tug had been secured using the tug’s line through the ship’s centre lead aft.
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As the ship approached the lock entrance then pilot instructed the stern tug to take some weight on the line, to reduce the ship’s progress. When the tug put weight on the line it parted.
The pilot ordered full astern, and the tug that was helping with alignment moved quickly in an attempt to counter the resulting ship’s swing to starboard. However, the ship’s port quarter contacted a pier leading up to the lock entrance, damaging the ship’s port side.
Probable cause
The tug recovered the parted line back on board. The messenger rope’s eye, which was connected to the eye of the main towline, had parted. The crew on the bulk carrier’s aft mooring deck had mistakenly placed the eye of the messenger rope instead of that of the towline over a bitt to make the towline fast.
- The messenger line’s eye was similar in size to that of the towline and large enough to be placed over the aft deck mooring bitt. Although the cordage used for the messenger was smaller in diameter than the towline, the sleeves used on the eyes of both ropes were similar in appearance and caused the the crew to mistakenly place the wrong eye over the bitts. The use of different coloured sleeves might have prevented the confusion.
- Towing operations in harbour are routine tasks that are potentially hazardous or can lead to avoidable accidents if crew members are not vigilant about them at all times. It is especially important that the officer in charge of such operations can maintain an overview of the operation to ensure that safe working practices are maintained and mistakes avoided.
