Research on hydrodynamic interaction indicates that if the speed of the ship near a bank is too high, the rudder may be less able to cope with the forces induced and control will be lost. The Nautical Institute highlights this in its latest Mars Report, in which an LPG carrier hit a barge being towed by a tugboat as a result of hydrodynamic forces.
Rotorcraft Pro gives an inside look at Brim Aviation's Columbia River Bar Pilots helicopter ops. CRBP uses an AW109SP to hoist ship captains onto ships crossing the dangerous river bar in Astoria, OR. This is part of a written/photo feature in the September 2015 issue of Rotorcraft Pro Magazine.