Abstract: A surfboard and hydrofoil assembly includes a surfboard having a generally elongated substantially flat board-like member with a density or specific gravity substantially less than that of water so that it will float. The surfboard has a top and a bottom surface and front and rear ends. At least one hydrofoil member is provided for supporting the main body of the surfboard out of the water when the assembly is moving forward at a relatively high speed. The hydrofoil member is removably secured to the bottom of said surfboard, and a tow rope or cable may be attached to the assembly. The surfboard assembly may be towed behind a motor boat or the like at high speeds, or may be used as a conventional surfboard, with said hydrofoil element being selectively removable.

Abstract: A locking and release mechanism includes two interlocked members, and two detents which hold the two interlocked members together. One of the two detents is magnetically operated and the other is mechanically operated. The mechanically operated detent involves the use of a mechanical operating member which moves through a channel, and an additional movable magnetic element which selectively blocks the channel. A special release member, which may be thought of as a key, carries both the mechanical member for extending through the channel and two magnets for operating the magnetically-operated detent, and the movable blocking member for the mechanically operated latch.

Abstract: A conventional electric utility meter is equipped with special circuitry and components which work in conjunction with an inserted magnetic card to regulate the supply of electricity to the structure to which the unit is attached. In addition to including the conventional dials which indicate overall kilowatt hours, the exterior of the unit includes a receptacle for the card and additional displays which show the kilowatt hours, and corresponding dollar value thereof, for the current payment period. The special circuitry includes a microprocessor, a set of magnetic read/write/erase heads, and a power relay. The circuitry interfaces with the conventional meter components by means of a photocell positioned above apertures or notches in the rotating disk of the meter. In the primary mode of operation, a prepayment card is inserted containing a predetermined kilowatt hour credit. The special circuitry senses this amount and adds it to the amount of power the customer is entitled to receive.