Abstract: A device for preventing or substantially reducing lateral slippage of an ect which is held to the surface of another object by suction means is provided. Suction pads are mounted so as to allow conformation with irregularities of the supporting object's surface and are provided with prongs preferably made of sharpened tool steel which are oriented to dig into the surface to preclude lateral slippage during operation.

Abstract: A linear milling machine adapted to be carried and controlled by a diver nts a hog mill cutter on a frame which itself is secured to the work preferably by a hold-down suction cup arrangement. A driven feed-screw advances the cutter relative to the work. Hydraulic motors drive the cutter and the feed screw as well as a pump used to establish the hold-down power. The suction motor and pump are mounted in a separate oil-filled and pressure-compensated casing. Another small and portable casing provides diver-controlled hydraulic flow regulation for the cutter motor, the feed screw drive and the suction pump motor. By controlling the drive speeds, cuts can be made utilizing only the suction grippers to firmly hold the frame to the work. At the end of each cut, the cutter is manually returned and the suction released to permit the frame to be quickly repositioned and secured for another continuation cut.

Abstract: A light-walled portable casing, filled with a hydraulic fluid, contains a gh-pressure water pump driven by a hydraulic fluid-driven motor. An externally-carried, suction-type gripper member engages the work object. Pumping evacuated seawater from the engaged surface to establish a secure differential-pressure hold-down force. A pressurized source of hydraulic fluid is applied through the casing to the motor. Fluid discharges from the motor directly into the casing to establish an interior casing pressure that pressure compensates the light-walled structure. Seawater evacuation eventually stalls the motor. When leakage occurs, pumping immediately resumes.