Abstract
An expression is derived for the maximum mean power that can be absorbed by a system of oscillating bodies in waves under a global constraint on their motions. The particular case of a single half-immersed sphere is used to show how the ‘point absorber’ result predicting capture widths in excess of unity must be modified. The theory is also applied to the submerged cylinder wave-energy device and curves are presented which show how the maximum efficiency is affected by restricting the motion of the device.