Abstract: An apparatus for extracting energy from waves traversing a body of water includes first and second tanks submerged in a body of water, first and second floating flap valves, a conduit, an air-propelled motor, and a valve. The tanks are spaced apart in the direction of movement of a wave, each has an opening close to the bottom for allowing water to enter, an air outlet above the opening, and contains a volume of air. The flap valves are arranged one in each of the tanks to selectively allow air to flow between the respective tank and the associated tank outlet but prevent the flow of water out the tank outlet. The conduit connects the tank outlets of the first and second tanks. The valve is disposed in the conduit and has first and second valve outlets directing air through the motor.

Abstract: A controller for a head rig edger saw for sawing the edges of a board that is cut from a log by a head saw includes a detector for determining the surface contour of the log to be sawed, along a line displaced from the face of the log; a computer device for selecting an edger saw line through the log from the surface contour to produce a board satisfying predetermined criteria; and an edger saw controller connected to the computing device for providing control signals to the edger for causing the saw to cut the board along the selected line.