Vehicle carrying Fast Ferries have often caused significant erosion and damage to berths since their introduction in 1990. During berthing, the high speed propulsion jets are deflected under the vessel and cause direct scour of the bed with scour holes up to 9m deep. Many Berthing structures have been underscoured or destabilised and scour protection damaged. This action is usually much more significant than traditional propeller action and requires the design and provision of appropriate scour protection.
Published advice only recently started to become available and the paper will seek to outline a current understanding gained from scour case histories and corresponding computational modelling. Scour protection types appropriate for high velocity jetting action will also be outlined and a basis for their design will be presented. The paper may be of use to Port Authorities, Design Engineers, Manufacturers and Operators.