Investigation into the roll behaviour of landing craft in deep water

Understanding and predicting the seakeeping and stability behaviour of a landing craft in both deep and shallow water is critical to assuring their safe and effective operation. The Australian Defence Science and Technology Organisation (DSTO) and the Australian Maritime College (AMC) are undertaking a research program to develop a numerical based capability to predict the motions of landing craft during operation. A series of model scale experiments have generated data for landing craft roll decay and motion response in calm water and in beam seas for both deep and shallow water conditions.

This paper presents the outcomes of an investigation into the roll behaviours of a geometric series of landing craft hull forms in deep water. Numerical simulations were performed using FREDYN, a non-linear, six degree of freedom time-domain ship motion prediction code. The results are validated using experimental data. An empirical method proposed by Ewers and Freathy [1] for calculating roll damping coefficients of barge like hull forms, in addition to the Ikeda-Himeno-Tanaka (IHT) and Fast Displacement Ship (FDS) methods, are evaluated against experimental data using the existing roll damping functionality within FREDYN [2].

The significance of predicting the seakeeping and stability performance of conventional landing craft, without the need for scale model testing, is discussed as well as the potential to use the tool to develop stability criterion, enhance platform operability and safety and facilitate simulator based operator training.