Preliminary considerations on a unified model for hydrodynamic forces

Choosing the correct formulation for setting the manoeuvring kinematic and dynamic quantities into non-dimensional form becomes critical when low speed manoeuvres are considered. The present paper details a selection of alternative formulations for this purpose, together with some proposed new possibilities. Different existing models are discussed, applied to some test-cases and compared, focusing in particular on the rate of turn, on all velocities in 6 degrees of freedom and on hull forces.