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174 the engine room is only sufficient to meet the ordinary demands for electric current, any excess that may be tem- porarily needed can be supplied by the emergency set, thereby avoiding the subjection of the main power plant to overloads and their potential dangers. Additions to the original electrical equip- ment of the ship may be made without augmenting the original power plant by a judicious selection of an emergency generating set of suitable capacity. With the ship in port, it is not necessary to keep part of the boilers and engine room in operation in order to have electric service available. For new ships of moderate size the emergency generating sets may, in many cases, be made to take the place of the usual engine room electrical equipment. If duplicate generators would ordinarily be installed, one generator could be re- placed by the emergency set, thereby lowering the first cost of the power plant and yet retaining all the factors necessary for adequate electric service under both normal and emergency con- ditions. In order successfully to meet operat- ing requirements on board a_ ship, emergency generating sets have _ been provided with marine fittings through- out. The fuel supply may be located either above or below the engine; while the water circulation system is such that it can utilize either sea water with free ‘discharge, or a closed circulating system with a storage tank. The latter affords better operation, however, due to the heating of the circulating water, which results in a more even cylinder tempera- ‘ture. For the wireless outfit, the necessary alternating current can be obtained through a small, compact and self-con- tained motor generator set; and if ‘storage batteries are also provided, a ‘simple arrangement of switches and wir- ing will serve to interconnect or to isolate, as may be required, the three sources of current supply, the batteries, engine room and emergency generators. The reliability of these emergency sets is such that their starting is prac- tically instantaneous; and if held sim- ply as reserves, the necessary periodical testing may be done without delay or difficulty and without requiring the ser- vice of a skilled operator. The gene- trator capacity selected for any ship will, of course, depend largely on the character of the work required and whether or not the output of the emergency set is to be used for other than wireless service and emergency lighting. From an engineering standpoint, there is no reason for limiting the service ren- dered by gasoline engine-driven gene- rating sets designed and built specially THE MARINE REVIEW for marine service solely to emergen- cies, as their fuel economy and high thermal efficiency at full load is well maintained at partial loads. Overloads of short duration can, if necessary, be safely carried, although this type of prime mover should not under ordinary conditions be subjected to heavy over- loading. If, in addition to the neces- sary periodical tests, the emergency sets are frequently used in connection with the ordinary electrical supply system of the ship, such use will give added as- surance of their dependability in a crisis, an important consideration aside from the economies incidentally obtained. Marine sets of this type are now available, ranging in capacities from 1 kilowatt to 25 kilowatts or even higher, designed specially for long continued and rigorous duty. The greatest factors of safety are conserved in all parts of both the engine and generator. The cylinders and valves are of such a size that the full rated output of the generator may be maintained without any possibility of overheating either. They operate quietly and can, therefore, be safely located near the wireless room. The amount of attention they require is practically negligible. Gasoline engine-driven generating sets have attained their present high electri- cal and mechanical characteristics through successive developments, brought about by years of exhaustive experiment, supplemented by critical observation and analysis of their performance under the most severe and protracted operation. Their use on shipboard involves no problems which have not already been satisfactorily solved, and those installed on a number of ships now in commission have amply demonstrated in service their ability successfully t o withstand the every-day, working pragmatic test. Efficiency in Repair Work* With the addition of the repair steamer Robt. J. Close, to the plant of the Superior Shipbuilding Co. might be said is the last word in efficiency in making repair to vessels with the least possible delay and without being neces- sary for vessels to come to the ship yard. The Robt. J. Close is constructed entirely .of steel, being 86 feet 6 inches long, 28 feet wide and 8 feet deep, with V-bow and square scow stern with screw propelling machinery. It is equipped with electric generator for operating the following electrically driven machinery and tools: Air Compressor, Electric Welder, Lathe, Drill Press, Frank A. Miller, assistant superintendent Superior Ship Building Co. in the Live Wire. May, 1915 Forges, Grinding Machine, Bolt and Pipe Cutter, Electric Drills. In addition to electric welder, there is an acetylene gas welding outfit, and full complement of air and hand tools including all tools necessary for boiler repairs of all kinds. A ten-ton derrick is also installed, being indispensable in handling plates and material when per- forming repairs to a vessel while at any other place than at the ship yard, and is also used for handling rudder, stern and stem forgings, anchors, propeller blades, crank shafts, etc., without loss of time to vessel to come to yard for loading or unloading when shipped via lake. The forward deck which is 43. feet long and 28 feet wide, gives ample space for handling of material, serves as an excellent work floor, and is used ex- tensively for the erection of staging thereon in making outside shell repairs, caulking of rivets and seams. When moored along side of a vessel, for some particular job, there are al- ways a number of other repairs the engi- neer and captain find are in need, and by having the proper equipment right at hand, we pick up a lot of odd jobs that would otherwise be done elsewhere. This is evidenced by the number of re- pair jobs done the past season, and for the month of September, 140 orders were filled with a total selling price of over $7,500.00. A complete stock of staybolts, boiler and heater tubes together with other material necessary for prompt repairs to boilers are always kept on _ board, as well as a stock of standard castings, viz: manhole covers and plates, chock sheaves, pins, hatch castings, stuffing boxes, manhole studs, gaskets, ceiling bolts, hatch wedges, ladders, etc. With the above equipment, which might be termed a floating repair yard and working in conjunction with our ship yard and shops, repairs of all nature are done quickly and econom- ically, and with the least possible delay to vessels while they are discharging or loading cargo. As an example of efficiency in making repairs, we submit the following facts in connection with repairs to the steamer Wainwright, which arrived at coal dock with damaged bow, and upon survey showed the following repairs were neces- sary, which were made: One sheer strake plate, two top side plates; one bulwark plate; one breast plate and ten brackets cut out, rolled and replaced. Double beading bar on both sides, cut loose. Stem cut 14 feet from top, straightened and new piece welded on, scarphed and replaced. These repairs were made while the