Collision: Crew Assumed it was Safe to Pass
The U.K. Marine Accident Investigation Branch has released its report on the collision between the high-speed catamaran Typhoon Clipper and the workboat Alison citing a pivotal assumption made by the crew of the Alison beforehand as a case of “normalizing” risk in a busy seaway.
At 1108 on December 5, 2016 the Typhoon Clipper and Alison collided adjacent to Tower Millennium Pier on the River Thames. Alison sank, and her two crewmen were rescued out of the water by Typhoon Clipper’s crew soon after the collision. Both Alison’s crewmen were suffering from cold shock but were released from hospital later the same day.
Neither vessel had properly identified the risk of collision. Nether made a sound signal which could have acted as a warning.
Alison’s crew had unberthed their vessel from Tower Millennium Pier and headed out into the river without properly assessing the shipping situation or making their intentions clear to other vessels.
Neither of the men on board Alison realized that Typhoon Clipper had unberthed and was likely to accelerate at any moment. They had assumed that she was still alongside and that it would be safe for them to pass close ahead into the fairway. When the crew of Alison became aware of the risk of collision, it was too late to take effective avoiding action.
Neither Typhoon Clipper’s master nor mate saw Alison before the collision. This happened because Alison was initially obscured by the pier and then moved into Typhoon Clipper’s visual blind sector ahead. Typhoon Clipper’s forward-looking closed-circuit television camera captured Alison’s movements; however, this image was not being displayed in the wheelhouse.
Neither of Alison’s crewmen was wearing a personal flotation device. This placed their lives in immediate danger when immersed in cold water. Alison’s owner/operator, Crown River Cruises Limited, had not conducted a risk assessment or developed procedures for the safe operation of its workboats.
The report highlights ambiguities in the Port of London Authority’s regulations regarding the keeping of lookout in vessels with “restricted visibility” and the use of sound signals by vessels intending to enter the Thames fairway.
The report is available here.