Bank effect caused the passenger vessel Juno the sailing boat Bolero, but Bolero was moored in the wrong place and difficult for the navigators to see until almost too late.
Says the Swedish Transport Agency report summary:
“On the 27th May 2010 at 09.00 am the passenger vessel Juno departed from Gothenburg with 27 passengers and 11 crew members on board. The destination was Stockholm via Göta kanal.
Göta kanal stretches from Sjötorp at lake Vänern to Mem in the Baltic Sea and is managed by Göta kanal AB (Kanalbolaget). West of Söderköping, the channel passes an area called Klevbrinken where a guest harbor, a camping site and a place for winter docking of boats are located on the north bank. After the harbor, towards Söderköping, at an old bridge abutment on the north side the channel width temporarily decreases from approximately 25 to 14 meters. This area is known to cause a bank effect for the vessels passing. Bank effect can be described as unequal lateral forces on a ship in narrow areas. The old bridge abutment was not part of the guest harbor and it was according to regulations prohibited for boats to moor there. Kanalbolaget allowed boats to be moored in the harbor 14 days free of charge in conjunction with launching or docking.
The sailing boat Bolero was launched in Klevbrinken after winter storage on the 19th May 2010. It was moored at the old bridge abutment since there was no space in the harbor.
On the 29th at approximately 07.20 pm, Juno left the lower locks of Duvkullen and continued towards Söderköping. The Chief Officer was conning the ship, an Able seaman was lookout and the Master had just come up to the wheelhouse. The crew on board Juno noticed that the harbor was full of boats and that a sailing boat was moored at the bridge abutment. The Chief Officer and the Master discussed the situation and realized that it would be a tight passage but decided to do it anyway as there were no other alternatives. If they stopped there was a risk that Juno would have drifted across the channel and collided with the boats moored in the guest harbor.
The Chief Officer slowed down and kept more south in the channel. Just before the abutment the bank effect caused Juno to turn to port towards the sailing boat. The Chief Officer put the rudder hard to starboard and gave a kick on the engine in an attempt to stop the turn. When he realized that a collision could not be avoided, he put the engine control handles to full astern to stop the ship. At 07.30 pm Juno collided with the Bolero which suffered extensive damage to its hull and took in water. There were no persons on board the Bolero at the time of the collision. On board Juno the roof above the portside bridge wing was slightly damaged when it was hit by the mast of the sailing boat.
The investigation pointed out that the factors contributing to the accident were that the sailing boat was moored so it prevented safe passage for Juno and other vessels. The crew on board Juno did not notice Bolero until they were out of the locks and had no knowledge of the location of the sailing boat before that. Kanalbolaget also accepted that the sailing boat was moored at a place where it was prohibited. As a result of this a number of recommendations has been issued to Strömma and Kanalbolaget
Full report in Swedish: The Passenger vessel JUNO collision with a sailing boat 29 May, 2010
(Thanks to Gunnel Persson, Maritime Investigation Unit, Swedish Transport Agency