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270 line and are therefore higher than the ordinary type, being 24 inches all around. The coamings are stiff- ened on the outside by 4-inch angles, bracketed to the deck and to the top flange of the 4-inch bounding angle on which the cover rests. Stif- fening of this sort is not possible with the usual sliding covers. From the standpoint of safety, it would seem highly improbable that anybody on deck would fall into the hold over a 2-foot coaming. Set in the under side of the cover is a continuous piece of %-inch square flax packing, on which the cover rests on the coaming flange. Around the coaming, spaced 18 inches apart, are swivel bolts fastened to the coaming. These swivel bolts when up in place fit into appropriate slots in the cover and the coaming flange, and have large wing nuts which when screwed down clamp the. cover securely in position. Even with these bolts not fastened, the cover could not slide out of the hatch open- ing, account of its weight and the stiffeners underneath. The crane spanning the hatches is of the traveling gantry type, mounted on rails running fore and aft the entire length of the deck. It has about 8 feet clearance over the hatch covers, and its extreme height, at end frames, is 8 feet. The end pieces are “A” frames, connected by two channel girders. The lifting tackle attaches to the cover at two points, and lifts it clear of the coaming. The crane is then run in a fore and aft direc- tion and conveys the cover to the space on deck between hatches, into which it fits. Lifting is done by an electric motor, fitted with an automatic brake which would prevent the cover dropping, should the power supply fail. This elec- tric motor also provides power for trav- eling. The operator stands on a hinged platform at one end, with all controls within easy reach. An automatic safe- ty device prevents the covers from being raised beyond a desired height, nor can lifting or lowering be done while traveling, and vice versa. It has been demonstrated in actual serv- ice that removing or replacing the hatch covers takes about one minute per hatch, using one operator and two men to hook on. When not in use the crane can be securely fastened to deck amidships or aft. Hand gear is provided for emergency use. Because of its rigidity, weight, wide coaming flange, and flax gasket, no tarpaulins are required. A_ very thorough, test was made for water- MARINE REVIEW tightness and not a leak developed. This single-unit hatch and arrange- ment for stowage is the invention of Capt. J. S. Wood, of the Wilson Transit Co., and its period of use on the ATWATER has demonstrated its entire practicability. The building of the hatch covers and the structural work in connection with fitting them was done by the Great Lakes Engi- neering Works while the special gantry erane was worked out by the Northern Engineering Works, Detroit. New Acetylene Generator Portable and Automatic A small generator for producing acetylene at low pressure for welding and cutting has recently been de- veloped by the Oxweld Acetylene Co., street, 380 East Forty-second New OXWELD 35 POUND CARBIDE CAPACITY PORTABLE LOW PRESSURE ACETY- LENE GENERATOR York. This outfit supplements a line of larger generators, a great many of which are used to supply pipe lines in shops where much cutting and weld- ing is done. The new generator, which takes 35 pounds of carbide at one charge, and is only 56 inches high and 24 inches in outside diameter can be transport- ed readily from place to place, thus pully, 1920 providing a portable supply of gen- erated acetylene gas. Empty, the gen- erator weighs only 210 pounds. An entirely new principle of feed control is used which might be called a heavier-than-water float. Referring to the accompanying illustration a vertical partition, extending nearly to the bottom into a water seal, divides the generator shell. One side is gas tight and contains the carbide hopper at the top. The upper part of the other side contains gas regulating and protective devices, and an automatic carbide feed control. Generation of the first acetylene causes water to rise on this side of the partition high enough to all but submerge a pan full of water, hung to a control lever. This pan normally acts as a weight acting counter to a spring, but as the water rises about it, its apparent weight is diminished and the carbide hopper valve is closed by the action of the spring. As acetylene is drawn off, water rises in the gas compartment and correspondingly lowers under the float, relieves some of the buoyancy under the water pan, which, gathering weight with the receding water, de- presses the spring and allows a small amount of carbide to drop into the generator, and restore a condition of equilibrium. Because of its low center of gravity, the generator rights itself when tilted at an angle of 30 degrees. It works perfectly at an inclination of upward of 10 degrees. No adverse effects re- sult if a generator while in operation is knocked over. Nearly all fittings are enclosed in the cylindrical shell and there is little, if anything, pro- jecting which may be injured by a fall on a concrete pavement. This generator has been submitted to the Underwriters’ Laboratories, Inc., and has been listed by them as an acceptable device for installation on insured premises. Silencer Extracts Noise Without Loss of Power ‘It is impossible of course with diesel or oil engines to ignore the question of noise. A wide opened unmuffled exhaust cannot be endured any better on board ship than in some stationary plants. In the case of a shore plant regard for one’s neighbors if not ex- ercised is likely to be enforced. Most diesel engined vessels are now equipped with silencers for their ex- haust. The silencer invented by Maxim for firearms has been adapted with suc- cess to the removal of all kinds of offensive sound waves in industrial life