Faulty Vessel Lookout In ‘Restricted Visibility’ Resulted in Collision



On 5 December 2016 the high-speed passenger catamaran Typhoon Clipper and the workboat Alison collided adjacent to Tower Millennium Pier on the River Thames. Alison sank and its 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.

Typhoon Clipper adjacent to the pier waiting for Silver Bonito to pass

Safety Issues

  • Avoiding collision starts with keeping a good lookout and assessing the shipping situation. In this case, neither vessel had properly identified the risk of collision
  • Use of sound signals in congested waterways can alert other vessels to your intentions; however, neither vessel made a sound signal which could have acted as a warning
  • Wearing a lifejacket is an important safety measure for workboat crews operating in congested waters
  • The rapid emergency response by the crew of Typhoon Clipper was a testament to the effectiveness of drills and being prepared for emergencies.

Tower Millennium Pier CCTV showing Alison emerging into the river close by the end
of the pier


  1. The crew of Alison had not effectively assessed the shipping situation and were unaware of the risk of collision with Typhoon Clipper until it was too late to take effective avoiding action.
  2. The helmsman of Alison was distracted because he was focusing on Silver Bonito passing by.  
  3. Alison’s crew made no attempt to indicate their intentions to other vessels nearby in a busy part of the waterway.  
  4. Neither the master nor mate of Typhoon Clipper saw Alison because it was initially obscured by the pier, then moved into the visual blind sector ahead and the CCTV settings excluded use of the bow camera.
  5. Neither vessel made a sound signal to warn others of their intentions to enter the fairway.

Typhoon Clipper’s bow CCTV camera image immediately prior to collision


  • This report highlights ambiguities in the Port of London Authority’s regulations regarding the keeping a lookout for vessels with ‘restricted visibility’ and the use of sound signals by vessels intending to enter the Thames fairway, resulting in a safety recommendation (2017/147).
  • A safety recommendation (2017/148) has also been made to Alison’s owner and operator, Crown River Cruises Limited, to update its safety management system to include procedures for the operation of its workboats.

Typhoon Clipper’s DCSA throwing a lifebuoy to Alison’s crewmen

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Source: MAIB