An apparatus that floats at the surface of a body of water over which waves pass, causing a nominally vertical axis of the apparatus to tilt away from an axis normal to the resting surface of the body of water. Tilting allows a fluid to flow through a channel that in an un-tilted apparatus would require the gravitational potential energy of the fluid to increase (i.e., to flow uphill), but, because of the tilt allows the fluid to flow through the channel in a downhill direction. Successive wave-driven tilts of the apparatus incrementally raise water to a head from which a portion of its gravitational potential energy can be converted to electrical power by causing the water to return to a lower level by flowing through a water turbine, or through some other apparatus that performs a useful function when supplied with a flow of high-pressure water.