Hydrodynamic Behaviour and Application Concerning a Transatlantic High-Speed Container Vessel

The purpose of this paper is to present some of the experience on hydrodynamic behaviour and application gained from the extensive and ongoing research and development program for the FastShip Atlantic Inc. TG770 project, known as FastShip.

The objective of the FastShip project is to establish a transatlantic service between dedicated ports of container vessels capable of carrying a payload of more than 10,000 tonnes at a service speed of approximately 40 knots.

Due to the extremity of such a design, applicable classification rules are more or less lacking. It has therefore been necessary to perform extensive hydrodynamic analyses to obtain reliable design loads and to develop new procedures for applying loads from the hydrodynamic analyses on the structural models of such vessels.

FastShip has been analysed for the prediction of load and motion responses by two different computer codes. The first code is based on a two-dimensional quadratic strip theory developed at the Technical University of Denmark and the second is based on a linear three-dimensional Rankine panel method developed at Massachusetts Institute of Technology. Both analyses are done in the frequency domain.

The paper will present a comparison study between the calculated load and motion responses and also compare these with results from model tests. It will be shown that good agreement is found despite the differences in the hydrodynamic analyses used and the relatively high Froude number for such vessels.

The state-of-the-art load application procedures by classification societies are based on linear wave theory, where external sea-pressures only are applied below the static waterline. Since FastShip experience extensive non-linear behaviour it has been necessary to develop an approximate load application procedure, which is based on linear hydrodynamic calculations and where the non-linear effects are included in a realistic way.

The paper will briefly describe the developed procedure and show examples of the load application from the FastShip project.