Abstract: A method and apparatus for automatically adjusting the down pressure exerted by an actuating device on a seed channel opener of a planting implement in order to maintain the seed channel opener at a predetermined depth. The method and apparatus includes a depth control device which senses the load on the depth control wheel of the planting implement and transmits a sensed load output to an electronic control unit. The electronic control unit includes a micro-controller which receives, monitors and analyzes the sensed load output and compares it to the predetermined depth value. When the micro-controller detects a change between the predetermined depth value and sensed output value, a signal is transmitted to a regulating control valve which adjusts the down pressure exerted by the actuating device on the seed channel opener to maintain the proper cutting depth.

Abstract: A Small Waterplane Area MultiHull vessel having an upper hull platform located above the design water line of the vessel which is maintained above the surface of a body of water by at least two cylindrical submerged hulls joined thereto by supporting struts. A buoyant core material is contained between inner and outer walls of the submerged hulls which define a cylindrical space in which a rotary propulsive means may be housed. In one embodiment, an engine means is situated on the upper hull platform and is joined to the rotary propulsive means through a work translating means which converts the output of the engine to rotary motion of the rotary propulsive means to provide a propulsive force.