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456 next suit this feature will be eliminat- ed and the trousers made of gun metal. The whole will be built upon, the ball and socket principle so as to give freedom to all the limbs of the diver. The inventors had hoped to test out their deep-sea armor in the rais- ing of the revenue cutter, Monawk, which was sunk in the. harbor of New York. She is resting about 90 feet be- low the surface of the water. The water pressure at the depth at which the MoHawk is laying is 38.9 pounds per square inch. Ordinary diving suits could not be used against such a pres- sure. Normally it has been impossible for a diver to work at a depth any greater than 80 feet, and then only very inefficiently. ; The New American Salvage Co., York, has attempted to eliminate the THE MARINE REVIEW side of a steel vessel, by energizing and de-energizing the magnets, and using them in conjunction with the screws. A drill and thrust arm are operated from within the machine, 6-inch lenses, 3 inches in thickness, are placed at intervals to permit of observation. A flexible armored cable carries two conductors from the ten- der ship to the machine, supplying the necessary current to the various motors within the machine. This cable has a buoy attached to it 25 to 30 feet from machine permitting the rest of the cable to hang slack so that the machine may be moved at will in the water. A telephone wire is carried within the cable per- mitting the operators to be in con- stant communication with the tender ship. Steel air bottles under high pres- sure carry enough air for the operat- October, 1919 panding hook. These hooks are band- ed together so that they will face outward or forward. The machine is about neutral in the water, and deter. mines its position by means of the lower propellers; the rear propellers move it forward and the magnetic thrust arm picks up one of the hooks attached to the pontoon. The four electro magnets are then energized and the drill drills a hole and by re- leasing the two vertical magnets the machine moves over until the hook is directly opposite the hole that has been drilled, the magnetic thrust 'arm then moves forward and inserts the expansion hook in the hole. This operation is repeated until a sufficient number of pontoons have been at- tached to the ship to raise it. The water in the pontoons is dis- placed by pumping air through a danger "of diving by proposing to use a device constructed upon the sub- marine principle. This is shaped like a ball and the men sent to work 'on the sunken vessel will work from its interior. It is known as the Sisson deep-sea diving machine, and has been tested in the waters of Lond Island sound. The machine is 7. feet in diameter and 9% feet in height. The machine weighs about 10 tons and is equipped with four 300-candlepower nitrogen lamps, two propellers on the rear and two on the bottom, permit- ting the operators to navigate the machine while searching for wrecks. On the front of the machine are lo- cated four electro magnets with a pulling power of about 2% tons each. These magnets are operated in pairs iby a motor within the machine which 'permits of the machine being moved to a predetermined point along the ors and while submerged they work under normal atmospheric conditions, irrespective of depth, due to the fact that air is permitted to enter the machine from steel air bottles at a predetermined rate per minute. While an air pump independently operated expels the foul air, in this manner maintaining normal atmospheric con- ditions. In case of emergency, the machine is equipped with ballast tanks which can be exhausted, thus per- mitting the machine to come to the surface of its own buoyancy. A man- ually operated pump is also provided for use in pumping out the ballast tanks, The plan of operation is more or less as follows: Pontoons of a pre- determined size are lowered along- side the wreck. They are equipped with cables placed about 2 feet apart; each cable has a float, also an ex- A COMBINATION PONTOON AND FLOATING DRYDOCK IS BEING TRIED BY THE BRITISH ADMIRALTY FOR SALVING SHIPS hose into the pontoons, the water going out through a = spring check valve. An improved type of machine is now being designed which will not have the different projections that the pres- ent type has. The lights, propellers and magnets will be concealed which will lighten it considerably and the operating mechanism such as drill and thrust arm will also be changed. The machine was not designed to work in tide races, rivers or bays where visibility is lacking. During the war the navy depart- ment made use of the hydraulic meth- od of passing chains under a vessel with some measure of success. A 'high-power hose was used on a ves- sel which was not extremely deep. The water pressure at that depth was 23 pounds and the hose threw water under a pressure of 150 pounds. a a cies 7