Prediction of bank induced sway force and yaw moment for ship-handling simulation

The Australian Maritime College (AMC) is Australia's national centre for maritime education, training and research. The AMC houses a full-scale bridge ship-handling simulator, which is used to investigate port development, ship manoeuvring and to improve ship and port safety and efficiency. To realistically simulate the manoeuvring properties of a vessel operating in restricted water it is crucial to model the effect of lateral banks. A study has recently been conducted at the AMC to improve the accuracy of the ship-bank interaction module on their ship-handling simulator. A series of semi captive, steady state model tests have been conducted with the model constrained in surge, sway and yaw to enable the measurement of the resultant sway force and yaw moment. The parameters investigated include; vessel speed, vessel draught, bank height, water depth, bank slope and ship to bank distance. The experiments were conducted at AMC's towing tank facility. The results have been used to develop a bank parameter that allows linear superposition of the sway force and yaw moment induced by lateral surface piercing and flooded banks. Multiple regression analyses have been performed on the experimental data to develop empirical equations to predict sway force and yaw moment induced by both surface piercing and tlooded banks. The prediction method has been incorporated intn the AMC ship-handling simulator, enhancing its ability to predict the motion of ships operating in restricted water. The relatively simple form of the empirical equations allows easy implementation into the simulation mathematical model and minimises the computer resources required to perform bank effect calculations. This paper brietly describes the model scale experiments conducted to investigate ship-bank interaction for the purpose of ship-handling simulation. A selection of results are presented highlighting the difficulties associated with accurate prediction of bank induced sway force and yaw moment. The bank parameter, which allows linear superposition of port and starboard banks in the regression formulae, is presented and discussed.