Published online by Cambridge University Press: 20 April 2006
This paper describes the calculation of the added-mass and damping coefficients of a submerged toroidal body that is undergoing a forced, periodic heaving motion. The velocity potential of the motion is expressed as an infinite sum of toroidal multipole potentials, and the problem is solved in a manner analogous to Ursell's classical solution for a submerged circular cylinder in two dimensions. When the torus is ‘slender’, in the sense that its tubular radius is small compared with its overall diameter, relatively simple closed-form asymptotic approximations for the addedmass and damping coefficients are obtained. This work is motivated by the proposed RS-35 design of ring-hulled semisubmersible platform.