Abstract: In a wave energy apparatus vertical movement of a float suspended in a body of water drives a power generator. Motion of the float is controlled by taking advantage of the movement of water on the upper surface of the float body. The upper surface can be used to generate hydrodynamic forces acting downwardly against the upward forces acting on the lower surface of the float body, effectively damping its movement in the presence of waves that might otherwise provoke undesirably large vertical movement of the float. The movement of water onto the upper surface can be controlled by adjusting the depth at which the float is suspended.

Abstract: Apparatus for extracting waves comprises a float (6) coupled to a drive mechanism (2) such that vertical movement of the float can be used to generate power. The float is freely suspended in a body of water, but subject to a flexible restraint (10, 12, 14) system for restricting its lateral movement. The restraint system can itself involve a suspended mass (10), which may be another float (6) coupled to the same or a different drive mechanism (2).

Abstract: Apparatus for extracting energy from waves comprises a float device coupled to a shaft such that vertical movement of the float devices drives the shaft. Movement of the float device is generated by the wave motion, and the mass of the float device is such that its natural frequency of vertical oscillation is substantially resonant with the frequency of a sea wave. The mass of the float device can be adjustable to achieve this.

Abstract: An electromagnetic machine which is suitable for use as a direct-drive, directly-coupled, mains electricity generator (14) to be driven by a low speed device such as a wind turbine (18), consists of one or more rotor rings (30) of many permanent magnets (40) of alternating polarity, with coaxial stator rings (28) of many laminated yokes (35), each yoke defining slots to locate coils (38). The yokes (35) and coils (38) form modules which are supported by beams (32) relative to the rotor rings (30). The rotor rings (30) may also be of modular construction. Manufacture and assembly are thereby simplified, and sub-harmonic magnetic flux components are suppressed.