The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

14 MARINE REVIEW. U. S. CRUISER MINNEAPOLIS, THE FASTEST WAR SHIP IN THE WORLD--A FULL DESCRIPTION OF A SHIP FROM WHICH A GREAT DEAL WOULD BE EXPECTED IN A NAVAL ENCOUNTER WITH ENGLAND. Accompanying this issue will be found a photo-chromotype illustration of the U. S. cruiser Minneapolis, reproduced from an oil painting made for the REVIEW by an artist who was sent to Philadelphia for this purpose. It has attracted probably as much attention as any marine scene published . recently and the readers of the REVIEW will be pleased at having a copy of it. In view of the fact that our war ships have become very interesting subjects during the past month a full description and illustration of one of the most formidable is given below. The Minneapolis was designed by the Navy Department, and built by the Wm, Cramp and Sons Ship and Engine Building Company, of Phila- delphia, Pa. The expansion of general designs into exact details, together with the piping systems and location of the auxiliary machinery, being done by the contractors. In the case of the machinery alone, this necessi- tated the making of some 300 separate drawings, a fact which indicates in away the magnitude of the task. The price for the ship complete was $2,690,000, and through a clause providing a bonus for excess of contract speed the builders were paid $414,600 more. The weight of the machinery was limited to 2,000 tons (about one- tenth of a ton per designed horse power), which weight included water in the boilers, and in condensers, pumps, pipes and stern tubes, but did not include weight of stores, heating apparatus, spare parts, tools in workshop, capstan, windlass, steering gear or winches. At the time of the trial this "included" weight amounted, to 1961.8 tons, leaving ample margin for escaping another penalty which the contract imposed on overweight, and which was $500 per ton up io 5 per cent., beyond which an additional $ro,- 000 was to be attached. mn The type of the ship is a protected cruiser, or commerce destroyer, 412 feet long and 58 feet beam, with a normal draught of 24 feet. The hull is of mild steel, the skin being of but a single course, of 2214-pound plating, (about 5-inch thick), There is a double bottom divided by water tight floors into 17 compartments, which extend across the ship through light- ening holes in the keel. Besides these, there are 198 other water tight compartments below the gun deck. A protective deck covers the hull proper trom stem to stern. This is made of two courses of 1%-inch nickel steel, to which, on the slopes over the machinery spaces, another course 1% inches thick is added, making 4 inches of steel where most needed. This protective deck joins the vessel's sides at 4 feet 6 inches below the normal water line, and "crowns" one foot above that water line. The main boiler compartments are not divided longitudinally, and are the larg- est compartments below the protective deck, the forward one being 67 feet long and the after one 69 feet. The engine compartments occupy a total length of 76 feet, excluding shaft alleys, making 212 feet in length of the hull for the machinery proper, or about half the entire length of the ship. Beside the commanding officer's quarters, there are rooms fitted up for the accommodation of eighteen ward-room officers, eight junior officers, and three warrant officers, and there is berthing space for 417 petty officers, crew and marines. The armament consists of one 8-inch 4o caliber rifle, two 6-inch 4o calibre rifles, eight 4-inch rapid fire guns, in q-inch sponsons, eight 6-pounder rapid fire guns,in 2-inch sponsons, four 6-pounder rapid fire guns, on upper deck, four gatling guns, four 1-pounder rapid fire guns, two torpedo tubes on bows, and two torpedo tubes on quarters, - The dimensions of the hull are: Length between perpendiculars 4It feet 7 inches; length on 1. w. 1., 411 feet 7 inches; length over all, Veet Io inches; beam, 58 feet 2 inches; ratio of length to beam, 7.08; depth of hold, top of floors to top of main deck beams, 37 feet 3 riches: draught mean, sea going trim normal, 24 feet; displacement normal, 8,005; ae | i Longitudinal Section U. S. S. "MINNEAPOLIS." per inch, 1. w.1., 37.2; area of immersed midship section, 1. w. 1, 1,212 square feet; area of 1. w. 1. plane, 15,600 square feet. There are three similar sets of main engines, each set in a separate water-tight compartment, the center engine room being abaft the star- board and port engine rooms, which are abreast of each other, as shown in the illustration. The type of engine is the inverted, direct acting three- cylinder triple-expansion. The housings, or supports are for each cylin- der an inverted cast steel Y frame at the back, aud two 8-inch forged hol- low steel columns in front. The valves are all of the single ported piston type, there being one for each high pressure cylinder, two for each inter- mediate, and four for each low pressure cylinder. The link motion is of the Stevenson type, double bar. Independent adjustable cut-off blocks are fitted to each link, with a range from .44 to .74 of stroke. There isa steam float lever reversing gear, which can also be adjusted to work by hand pump and oil, there being a common piston rod for both steam and oil pis- tons and cylinders. The operation of reversing by steam is nearly instan- taneous. ine The high pressure valve takes steam in the center through a 15-inch steam pipe. It exhausts at ends to the intermediate valves through four short 14-inch bends, (two on each side) which pipes form the first receiver. The intermediate valves exhaust from the center through a single 23-inch pipe (r. ducing toa long 19-inch pipe between the two ends of the low pressure cylinder), this forming the second receiver. The low pressure valves exhaust to the main condenser from the center through two 22%4- inch pipes. The main steam pipe from the boilers to the engines is of lap welded steel, 34-inch thick and 2z0inchesin diameter as far as the first engine branches. The data of one main engine follows: Number of cylinders three; diameter of cylinders, H. P., 42 inches; I. P., 59 inches; L. P. 92 inches; stroke, 42 inches; diameter of valves, H. P. (one) 18 inches; I.P., (two) 23 inches; lL. P. (four) 2r inches; diameter of piston rods (all) 8% inches; length of connecting rods, center to center, 84 inches; distance between centers of cylinders, 9 feet 714 inches. The crank shafts are interchangeable, there being a separate section for each crank. The thrust and propeller shafting is 153( inches diameter and the axial hole 7% inches, tapering to 4% at propeller ends. The cen- ter shaft runs parallel to the keel, while the wing shafts are inclined up- wards, at about 1 foot 11 inches in 100 feet, and also inclined outwards at about 3 feet 101% inches in 100 feet from the center line. This brings the position of the center of each wing propeller 13 feet 5 inches forward, 3 feet 3 inches above, and 12 feet 5 inches outboard of that of the center screw. The lines of the wing shafts if projected would meet at about 4 feet 9 inches above the base line, and 156 feet forward of the center of gravity, between frames No. 16 and No. 17. Each engine has a thrust bearing of the horse- shoe pattern, fitting eleven collars turned on the thrust shafts. These col- lars are 334 inches deep and 2 inches thick. The thrust surface of each shaft is 2,527 square inches. There is one main condenser in each engine room. They are cylin- drical, and made of composition throughout, 14 feet 9 inches long and 6 feet 7 inches diameter. Steam is outside of tubes. The two auxiliary con- densers were furnished by the Wheeler Condenser and Engineering Co. There are three double main air pumps, Blake vertical inverted twin cylinder, and two centrifugal pumps, for each main condenser, driven by two Io inch by 6 inch simple engines coupled together, These pumps are also connected to draw from the bilge and main drains, and their discharge may be direct overboard, if desired, without its passing through the con- densers. The capacity from the bilge is 6,750 gallons per minute for each pump, aggregating 40,500 gallons per minute for the six pumps and about equalling an amount of water which would enter through a 27-inch hole in the ship's bottom. Of the other steam pumps in the ship, there are eleven with bilge connections having an aggregate capacity of 7,400 gallons per minute, which added to that of the circulating pumps makes a grand total of 47,900 gallons per minute. The pumps connected with the evapo- i i rn =