Very lucky indeed

Thursday, 25 June, 2015 - 08:00
Emergency tugboat springs into action off the coast for Borkum – efficiency and the ability to weather storms are the boat requirements. The photo depicts Nordic’s predecessor Oceanic of the shipping  company Bugsier. (Photo: Bugsier)
Emergency tugboat springs into action off the coast for Borkum – efficiency and the ability to weather storms are the boat requirements. The photo depicts Nordic’s predecessor Oceanic of the shipping company Bugsier. (Photo: Bugsier)

Is the danger for offshore wind turbines posed by drifting ships with no engine power currently being underestimated? In the case of a multi-purpose freighter in the middle of February, rescue came in the form of a customs ship that just happened to be patrolling nearby. Organised emergency strategies look somewhat different.

Sunday, 8th February 2015. Late at night, in stormy seas, the multi-purpose freighter Kelt got into an emergency situation. The main engine stopped working – meaning it was no longer possible to manoeuvre the ship. Helpless and without any possibility to take action, the crew looked on as their ship was tossed around by the wind and waves. The situation was especially dangerous because the ship was drifting towards the offshore wind farm Riffgat. Therefore, on Monday morning the command centre for the Ems region became involved.

It ordered the customs cruiser Borkum, which was patrolling in the area, to head for the scene. At 7:35 a.m. the crew managed to connect a towing line to the Kelt and to stop her from drifting. One hour later the ­emergency tug Nordic arrived. Together with the customs cruiser, the Nordic then kept the 80 m long freighter in position. After a further hour, ships from the Dutch shipping company arrived on the scene and towed the Kelt to the Dutch port of Delfzijl.

This was not the only time so far this year that a ship has drifted out of control in the North Sea. In the middle of January, the oil tanker Silver Carla was involved in a similar incident. The classic combination: storm, huge waves and failed technology. At 2:18 a.m. the captain reported the failure of the ship’s engines to the control centre ­German Bight Traffic. He also asked the agents of the shipping company to organize two tugs. Since the ship was drifting with a speed of about 4 knots – around 7.5 km/h – towards the East Frisian ­Islands, at 4:00 a.m. the control centre German Bight Traffic sent the emergency tug ­Nordic on its way.

It could have been worse

Especially the Kelt incident poses important questions. The ship had already been adrift for several hours before the customs cruiser Borkum arrived and was able to almost stop the ship from drifting. The fact that the Borkum was able to help, and could stabilize the situation, was a matter of luck. “The Borkum was in the area purely by chance”, confirmed the Head of the Water and Shipping Office Emden (WSA), ­Reinhard de Boer. The emergency tug that was really responsible ­arrived at least an hour later.

A ship in stormy seas functions like a huge sail and can develop an astounding speed – depending on the wind strength, the tide and the area of the ship that is above the waterline. The Kelt, which is 82 m long and 12.5 m wide, has a little over 1,000 m2 that can catch the wind. The WSA quotes the drift speed as having been 1.5 knots. This means 1.5 nautical miles per hour, around 3 km/h. This is actually a moderate drift speed, possibly because the ship was being blown against the direction of the tidal current. But if we assume that the Kelt drifted for five hours, this means that the ship had already got 15 km closer to the Riffgat wind farm before help in the form of the customs cruiser arrived, and up to 3 km further before the emergency tug turned up.  

The seriousness of the situation is shown by the fact that the closest distance to the wind farm boundary was only 1.5 nautical miles. The first wind turbine was only half a ­nautical mile further on, so a total of two nautical miles. The drifting Kelt would only have needed 80 minutes to cover this distance.

Are the risk analyses correct?

If the customs cruiser had not intervened, the emergency tug would have arrived at about the same time as the Kelt collided with the first wind turbine. Or put another way: much too late! The ship would probably have rammed the wind turbine foundation broadside. Predictions of what would have happened next are only speculation; many factors would have played a role. It seems certain, however, that the turbine would not have withstood the impact of the 3000 t ship – even though it was only moving at walking speed.
From a shipping point of view this would be the least important consequence. Worst case: the remains of the foundations – several thousand tons of steel – rip the ship’s hull apart, perhaps even the double hull of a loaded tanker. The sensitive mudflats of the German Bight would be polluted for decades.

It was pure luck that the first shipwreck in a wind farm was narrowly avoided in February. But whether the protection of the ­“Wattenmeer” mudflats, which provide many jobs in the tourism industry, and the safety of expensive power generation equipment and ships should be left to luck is a question that urgently needs to be answered. “There are voices in the industry that would like to increase the tug capacity in the German Bight”, confirmed the Manager of one of the companies involved. “This automatically means that the studies and analyses on shipping safety would need to be re-examined.”

Jörn Iken

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