Unexplained accident on the River Tees

Damage to bulk carrier Gülnak, including the loss of half of her port side anchor, on the River Tees in April 2019 has proved to be an unusual case, in that the UK Marine Accident Investigation Branch (MAIB) has not been able to establish how or why it happened.

On April 18th 2019 Turkish-flagged bulker Gülnak overshot her turn and struck the moored bulker Cape Mathilde, which was alongside the Redcar bulk terminal in Teesport, England. Both vessels were damaged, but there were no injuries and there was no pollution reported.

The MAIB determined that Gülnak lost control of her heading towards the end of a turn to port in the main navigation channel. The turn to port could not be fully arrested, despite full starboard rudder and full speed ahead.

In the investigation that followed, MAIB examined the actions of the bridge team, the Gülnak’s manoeuvreing characteristics, the state of her steering gear and any possible hydrodynamic effects. There was no rudder angle or engine speed data, as this was not recorded on the vessel’s VDR, but bridge audio provided evidence of the rudder and engine commands given. No direct cause of the accident was identified.

After Gülnak had overshot the turn the pilot and master realized that Gülnak would strike the Cape Mathilde. The pilot ordered full astern.

The impact resulted in indentation and steelwork damage to Gülnak’s port bow and the shearing of Gülnak’s port anchor at the stock. Cape Mathilde’s port side was damaged above the waterline at her Number 1 and Number 2 wing ballast tanks, with the lower section of Gülnak’s port anchor embedded in the forward part of the Number 1 ballast tank. No injuries or pollution were reported.

The MAIB noted that all the factors in the case appeared to indicate a normal, uneventful transit. The wind was light, the current was negligible, and a high tide meant that there was 25ft of under keel clearance throughout. There were no problems steering the vessel before the turn that led to the casualty. Crew experience was not a likely factor as the master had 16 years at sea and the pilot had been in the industry since 1977, with 25 years local pilot knowledge.

Bridge audio recordings showed that all helm and engine orders given by the pilot were repeated by the third officer, who informed the pilot as soon as the action ordered had been completed. In the case of helm orders, this was within seven seconds.

An underwater inspection of Gülnak found that the rudder was undamaged and that the vessel’s electro-hydraulic steering system was operating well, with the rudder moving from hard-over to hard-over in 21 seconds.

MAIB therefore concluded that “the factors contributing to the inability to fully arrest Gülnak’s turn are not readily apparent”, although it added that, despite the 25ft clearance, “the possibility that Gülnak’s heading and directional stability were influenced to some degree by shallow water effects cannot be eliminated”.