Evaluation of Multi-Vessel Ship Motion Prediction Codes

Abstract

Abstract : An evaluation of six different multiple body ship motion prediction codes, MVS-CSC, MVTDS, AQWA, ShipMo3D, AEGIR, and LAMP-MULTI, was performed by the Naval Surface Warfare Center, Carderock Division (NSWCCD). Each of the codes in this evaluation was chosen based on its accessibility to the Navy or its use by US regulatory agencies. The evaluation was performed in two parts. The first part compared the capabilities of each code against a matrix of capabilities that were important for predicting the usefulness of a base at sea to transfer military equipment and personnel from a larger to smaller vessel. Results of this evaluation show that all the codes have the same capabilities for estimating the environment, calculating the motions of the ships in any configuration with respect to each other, and accounting for the hydrodynamic effects between the hulls. The major differences in the capabilities of the codes were in the non-hydrodynamic factors and in the degree of complexity used to model the hydrodynamic factors. AEGIR, LAMP-MULTI, and AQWA allow for user supplied force routines in the time domain and AQWA, LAMP-MULTI and MVS include some built-in models for mooring lines and fenders. Also, the autopilot feature for multiple ships was available only in the MVS and LAMP-MULTI codes. The second part of the evaluation correlated two-ship model data from a test performed at the Maritime Research Institute Netherlands (MARIN) with the output from each of the codes. This correlation of the codes yielded differing results. Overall all codes predicted heave and pitch motions within 10% of the model test results except for the CSC MultiVessel Simulator (MVS) and the D&P MultiVessel Time Domain Simulator (MVTDS) which was 30% off of the model tests.