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October, 1919 The diver directed the nozzle, which was extremely long, at the sediment under the vessel and when a passage had been blown completely through, the nozzle was disconnected and a ca- ble drawn under. Chains were. at- tached to the end of the cables, and these were later attached to specially constructed pontoons. In cases where the ship has settled deep into the sand and mud at the bottom of the ocean it would be im- 'possible to dig under it with either a hose or any other method now in use because as 'fast as the sand was removed it would fill in again. To meet such a condition as this, the burrowing machine has been invent- ed and is being: promoted by the COLLAPSIBLE PONTOONS MAY BE USED TO RAISE SHIPS United States Ship Salvage Partici- pating Syndicate of New York. This is a box-like machine which is pulled through the sediment and under the ship by two screw-like blades operat- ing in opposite directions. The blades . are operated by an engine supplied with water under pressure. It has a rudder on the rear end which will guide the machine up or down as is needed and attached to this is a ca- ble which is pulled under the ship as the machine burrows. Once through the hose is disconnected and the ma- chine lifted out of the water from the other side of the ship by a der- rick, _ A further adaptation of this burrow- Ing principle has been devised by the Same people by an application of the tank which was invented during the war. Instead of two traveling belts, however, this machine has four, two Working together in opposite direc- tions. The nose of this machine THE MARINE REVIEW has a hydraulic spray attachment which will assist the progress of the "caterpillar" by blowing away sedi- ment. This machine also is operated by hydraulic power and draws chains under the ship. The Interocean. Submarine Engi- neering Co. hopes to obviate the ne- cessity of using pontoons in deep- sea work by utilizing the water-tight compartments of the sunken vessel. Where this practice is followed it will be necessary to send divers down to seal all the hatches and holes. In the shell of the water-tight compart- ments a hole will be cut over which is fitted in patented valve plate. Through this valve compressed air can be pumped into the compartment . and the water forced out. This scheme was used in a modified way to raise the American submarine F_4, in Hawaii, a few years ago. Con- siderable study has been given. to the effect of the water-tight compart- ments on a sinking vessel. It has been discovered that some of these vessels will float below the surface of the water for a long time, or at least until water gets into the com- 'partments and forces all the air out. Then the vessel turns turtle and sinks to the bottom. It is believed that by sealing the hatches and filling these compartments with compressed air again, the vessel will revert to her upright position while coming back. to the surface. _In harbors it is possible to use pon- - toons and other simpler means of rais- ing a ship, but it becomes increasing- ly difficult to. use pontoons in the ocean. The large pontoons the Eng- lish have built, however, may be con- sidered somewhat different. These, constructed of cement, are in reality the half sections of a dry dock. It is planned to lower one on either side of a ship, pump the water out and bring her to the surface. But after diving for a ship, it is often found necessary to cut away some of the structure in order to get to work on the vessel. Sometimes it has been found utterly impossible to do anything with a sunken ship because it was impossible to cut away certain structures. Merritt & Chap- man, of New York, believe they have largely met this problem by the use of an underwater cutting machine. This machine is an adaption of the acetylene cutting flame. It has been patented in this country. In the Chapman system of under- water cutting the flame is supported by a constant electric arc. The Ger- mans also have a method where the flame is supported by compressed air and a shield. The flame, however, 457 is started by an electrical spark. The English likewise have a machine to cut underwater but theirs is an elec- trical method entirely.. Salvaging work is still progressing along the accepted lines, while inven- tive genius has been exhausted upon the many ideas advanced for raising the numerous vessels that were tor- pedoed and mined in the ocean. But daring attempts to raise vessels from the bottom of the ocean will probably not have the sanction and the sup- port of the commercial salvagers for some time to come. They hesitate to work on experiments because such work does not hold profit for them. It is too much of a gamble. Com- mercial salving must be assured of SKETCH SHOWING HOW BURROWING MACHINE WORKS a reasonable return upon its expendi- tures. Since the war salvage experts have been striving to find a way to do away with diving. If this can be ac- complished a great advance will have been made in the art of salving. One of the ideas advanced is known as the DeVito method. Instead of hav- ing several pontoons, but two pon- toons are used hinged together at each end. These hinges are operat- ed in connection with an air-cylinder. When lowered the hinges are wide open and the pontoons will lay on either side of the sunken vessel. Air is then pumped into the cylinder which raises, closing the hinge and bringing the two pontoons close to- gether, clamping them to the ship in a vise-like grip. The grip of the pontoons once established, water is pumped out of the pontoons thereby raising the ship.