General view of an amphibious tour bus which held 30 passengers on board sank in the Albert Dock. PRESS ASSOCIATION Photo. Picture date: Saturday June 15, 2013. One of Liverpool’s fleet of Yellow Duckmarine tour buses began sinking just before 4pm today in Salthouse Dock at the front of the Albert Dock complex. A spokesman for the Maritime and Coastguard Agency said 30 passengers were on board. See PA story ACCIDENT Duckmarine. Photo credit should read: Peter Byrne/PA Wire