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216 THE MARINE REVIEW es July, 1912 STAIRWAY LEADING To GALLERY Deck, Forwarp, City oF Detroit III tons. It is made in three sections connected by flanged couplings which are. recessed into the hubs of the crank arms. The crank arms are sunk into the pins, thus making the crank shaft perfectly rigid from end to end and avoiding all the trouble incidental to loose pins, wedges, etc. The crank shafting and pins are 'hollow throughout. The connecting rods are 20 ft. center to center and 13% in. diameter at the center of their lencth: . 'The crank pin end is fitted with round brasses lined with white metal, the caps being forged steel worked out of the main forging. The crosshead end is forked and fitted with flat- bottomed brasses and wrought steel caps and bolts. Each connecting rod weighs approximately 10 tons. The piston rods are 12 in. diameter and the crosshead slippers are steel cast- ings faced with white metal. The main bearing pedestals, six in num- ber, are massive steel castings, rigidly bolted to the foundations, which are part of the ship structure, and braced together to insure stiffness when the engine is working. The caps are steel castings, box section, the' bearings being circular shells lined with white metal. The guide struts are con- nected to the main bearing castings by a T-end through which the main bearing bolts are extended, and to the cylinder by round flanges and bolts. Midway in their length they are supported by vertical columns carried from the ship's floors. Each cylinder is cast complete with its valve chests, thus avoiding all un- necessary and oftentimes troublesome joints. The front heads are also cast with the cylinders and are strongly ribbed to distribute the strain from the guide struts. The finished low- pressure cylinders weigh approximate- ly 2734 tons each and are excellent specimens of the founders' art. The main air pumps, two in num- ber, are of the vertical, single-acting plunger and bucket type, driven through .heavy forged steel bell crank levers, from the low-pressure cross- heads. Each air pump crosshead also carries the plunger of a single-acting vertical feed and bilge pump. The condensers are built up of riveted plate and each low-pressure cylinder connects with its own con- denser through a 24-in. exhaust pipe. Copyrighted, Detroit Publishing Co. The reversing of the engines is accomplished by means of a direct- acting steam gear, but a_ powerful hand-operated worm reversing gear is fitted for emergency use. The handling gear levers-are all conveniently grouped in a quadrant on the working platform above the cylinders and, massive though the moving parts are, the reversing, etc., is accomplished with the greatest ease and facility. The main throttle valve, 17 in. in diameter, is of the Schuette-Korting balanced type, oper- ated by .a simple lever and is fitted with an 8-in. "by-pass" or maneuver- ing valve which is sufficiently large to operate the .engine up to half speed. The lubricating system is elaborate and complete, as are the appliances to assist in the overhauling or lifting of the engine parts. The paddle wheels are unusually stron; and heavy and are designed to suc- cessfully meet the severe ice condi-. tions met with in the early part .of the season. The centers are of cast steel and the arms of forged iron with the large gudgeon busses forged on and bushed with lignum-vitae. The wheels are 30 ft. 3- in. outside