Abstract: A covert attacking swimmer is discovered and acquired by an echo-search aratus. Once acquired, a search and destruct vehicle type weapon is launched which seeks out the attacking swimmer and when in range therewith shoots him with lethal electric fields or spears.

Abstract: A variable height work holder for holding a work piece on a work table, such as a machine tool table, the table having a tie down bolt upwardly extending therefrom, the device including a heel member having an upwardly extending thick wall tubular portion with an upwardly spiraled upper surface defined by a series of steps, a pin affixed to the heel member coaxially of the tubular portion and an elongated clamping bar having an opening adjacent the inner end thereof slidably receiving the pin, the portion adjacent the outer end being configured to engage a work piece, the clamping bar having, intermediate the ends, a portion for receiving a tie down bolt therethrough, the spiraled stepped upper surface of the heel tubular portion providing means for supporting the inner end of the clamping bar at variable heights with respect to the work table.

Abstract: A device employing a permanent magnet is used to provide a sweep for magnetically activated marine mines.