Seakeeping behaviour of a frigate-type trimaran

The motion behaviour of a frigate-type trimaran was studied in a joint co-operation between the Royal Netherlands Navy (RNLN), the, Maritime Research Institute Netherlands (MARIN) and Det Norske Veritas (DNV). The starting point for the study is a series of model tests for a frigate-type trimaran conducted at MARIN. Frequency and time-domain linear and nonlinear hydrodynamic calculations are validated against the model tests. The overall seakeeping behaviour ofthe vessel is discussed and particular attention is paid to the roU motion. Parametric roU is discussed and test results are presented. The use of passive and active fins to reduce the roU motion is evaluated in stem quartering seas. The nonlinear effect on the roU motions of the intermittent wetting of the side hulls and the size of the side hull volume is evaluated. The paper ends with a discussion on seakeepmg and design load assessments for trimaran vessels.