MACHINERY OF THE "CITY OF ROME."
In a previous paper a full and detailed description was given of the hull of this steamer, and the means employed in making her not only the largest vessel now afloat, but also the strongest built wooden hull that up to this time has ben launched upon these inland seas. Pleasure is taken in laying before the readers of the Herald a full and detailed description of the largest engine of its kind now in use upon the lakes. The engines and boilers were built and furnished by the old and well known Cuyahoga Works of this city, and are from new drawings and designs, which contain several valuable improvements not in use heretofore, a description of which will appear in their proper place.
The CITY OF ROME has two double furnace return flue boilers, the shells being 9 feet in diameter, and made of the best Otis steel plate 9126 inches thick, and the horizontal seams secured by three rows 0f 3-4 inch rivets. The boilers have steam chimneys 6 feet 6 inches in diameter and 6 feet high, to insure dry and superheated steam for the engines. Under each boiler is a heavy boiler iron pan, resting on wrought iron girders beams, and over them is I. W. Beache's patent metalic covering to prevent loss of heat by radiation. This covering was put on by the firm of Kennedy, DeForest & Parsons, of this city. The boilers have been subjected to the Government test of 150 pounds pressure per square inch, and will carry steam at 100 pounds pressure.
The engines are of the style known as compound engines, 32 inch bore and 48 inch stroke, and one low pressure cylinder 60 inch bore and 48 inch stroke; one being placed forward of the other, and both connected to one shaft. The cranks of each engine are placed directly opposite to each other, and not as it has been the practice heretofore, at right angles with each other.
The Cuyahoga Works were the first to adopt this plan on lake steamers, they having constructed the engines of the AMAZON in this way several years ago. The great value of this arrangement of the cranks is, that when one engine is making its downward stroke, the other engine is making its upward stroke, and the shock of one engine is entirely counterbalanced by the other, and, as a consequence, the hull does not receive any of the pulsation of the engines, as it would were a single crank used; or, were two cranks at right angles used.
The valve gear of the CITY OF ROME contains some new features which cannot be fully described in a newspaper article. The steam first enters a chamber containing an adjustable cut-off valve, arranged to cut off the steam at different patrs of the piston stroke; from this chamber the steam enters the usual main steam chest of the high-pressure cylinder; the valve of which differs from the ordinary valve by not having an exhaust chamber beneath it, this not being required; after the piston of the high-pressure engine has made its stroke, the steam contained within the cylinder is allowed to pass through a transfer valve to the opposite side of the piston of the low-pressure cylinder, and, when this piston has made its stroke, another set of valves open a passage to the condenser. The advantage of this system is, that the steam is changed from one cylinder to the other in the shortest, and in the most direct manner, and without losing its tempreture or pressure by expansion in chambers, or receivers, where it does no work; beside, each valve is capable of independent adjustment so as to use the steam to the best possible economy. The engines are reversed by the use of a pair of straight links, which are moved by the aid of a seperate steam cylinder, thus relieving the engineer of much of the labor usually required in handling such massive engines. The engines are very heavy and strong in all their parts, and in addition to all the parts usually used upon first-class marine engines, they have the "universal coupling," which was also introduced in the lake marine engines by this company for the first time in the steamer AMAZON.
Among the new and what will doubtless prove to be one of the most valuable improvements of the CITY OF ROME's machinery, is what is called a starting or pry off engine, which has recently been invented and patented by Mr. J. F. Holloway, the president and superintendent of the Cuyahoga Works, and which is now for the first time used on a marine engine. It is a well known fact among the owners and operators of lake steamers that engines, while being worked slowly in and out of port, are liable to "get on the center," as it is called, or, in other words, to stop at the extreme end of their stroke, where they cannot be started by the application of steam to the piston. This is most likely to occur while the steamer is passing through bridges, or working in a crowded port, and cannot work the engine with sufficient speed to insure its passing the centers with certainty, and as a consequence where, if the engine does become for the time powerless to move, great damage is likely to be done, by running into docks, bridges, or agains other vessels. The usual means employed to get the engine started, when thus caught on the center, is by sending men below and with the use of a pinch bar prying the engine ahead or back as the case may be. The purpose of this new invention is to put it within the power of the engineer by the use of the steam starting engine to turn the engine off its center, without calling in the aid of his assistants or firemen, or without leaving his post at the throttle valve; and the ease with which it is accomplished makes it seem strange it has not been thought of before this. Upon the main shaft in the run of the vessel, where it is entirely out of the way, is placed a cast iron wheel, on the face of which a series of V friction grooves; at the side of this wheel and somewhat above it, is placed a simple steam cylinder, on the piston rod of which is a short, straight block of iron which is grooved to fit the grooves upon the wheel. This sliding block is so arranged as that it may be pressed or held firmly against the friction wheel whenever it is desirable to turn the shaft. Now, if the two surfaces are thus held in contact, and steam is admitted to the piston of the steam cylinder the sliding block will move the length of the steam cylinder and rotate the engine shaft a portion of its revolution, and thus will place the crank pin in a position to be further moved by the main engine. All this can be done so easily and so rapidly that no delay will occur in handling the engine, and as a further consequence, all risk of damage from this cause will be obviated. The starting engine is so arranged as that it will disengage itself from the wheel on the shaft at each end of its stroke, or when not in use, and is thus freed from any liability of damage should the main engine start while it is in gear. Vessel owners who have been called upon to respond to suits for damages resulting from the "engine getting on the center," will doubtless value highly any improvement that shall do away with the risks in the future. The CITY OF ROME is supplied with a large Worthington Duplex Pumping Engine for supplying the boilers with water and for use as a fire pump, and has upon its main deck a pair of F. Murgratoyd's patent reversing engines arranged so as to work the deck bilge pump if required, make sail, or work the windlass by means of an endless wire rope. The steamer in all its parts, has been built under the supervision of Captain B. Wolven, who is a part owner and master of her.
Wednesday, June 1, 1881
Steam screw CITY OF ROME. U. S. No. 125914. Of 1908 tons gross; 1594 tons net. Built Cleveland, O., 1881. Home port, Sandusky, O. 268.2 x 40.2 x 20.3 Crew of 17. Of 500 indicated horsepower.
Merchant Vessel List, U. S., 1902