MECHANICAL AND USEFUL ARTS. 33 



girders, or only so much as is necessary for the protection of the 

 gun deck and deck below it may be placed on the girders, the re- 

 mainder being placed on the ship's sides, or otherwise connected 

 together. — Mechanics' Magazine. 



A STEEL TROOP-SHIP. 



A remarkable ship has been constructed on the banks of the 

 Tees, at the yards of Messrs. M. Pearse and Co., Stockton-on-Tees. 

 This is a Steam Troop-ship, and the largest river steamer in the world, 

 and i.s intended for the navigation of the Lower Indus. She is 

 constructed entirely of steel, and exceeds in length all ships hitherto 

 built, except the Adriatic and the Great Eastern. The following 

 are her principal dimensions : — Length over all, 375 feet ; beam 

 moulded, 46 feet, the paddles projecting 13 feet more on each side, 

 making a total breadth of 72 feet. The extreme depth amidships is 

 only five feet. This is uniform throughout, the vessel being quite 

 flat- bottomed, except at the ends, which are alike, and are spoon- 

 shaped. The paddle-wheels are 23 feet in diameter, and are 

 driven by engines of 200 nominal, but capable of working up to 800 

 horse-power. She is divided into compartments by twelve water- 

 tight bulkheads : has two decks, containing three ranges of beds, 

 separated by two passages. These latter are built in two houses, 

 each 100 feet long, in a somewhat similar mode to the saloons of 

 the American river steamers, and leaving a clear gangway outside 

 all round the ship. The ventilation is by an apparatus steered by a 

 novel contrivance. Two blades at each end, diverging from each 

 other at an angle of 70°, are made to dip alternately into the water 

 at an angle of 3iT, right or left of her course, and the slightest im- 

 mersion on either side is immediately effective beneath the flat 

 bottom of the enormous vessel. The necessary firmness to this great 

 but apparently frail structure is secured by two girders, fastened to 

 two parallel keelsons at the sides of the vessel. These are formed of 

 steel plates, and the keelsons are 300 feet long, from which the 

 girders spring in a chord, whose curve is 18 feet. To these the 

 whole framework of the vessel is braced and trussed, so as to give 

 it enormous strength. The quantity of steel used in her construc- 

 tion is only 270 tons ; she will accommodate 800 soldiers, besides 

 officers and crew, and draw only 2\ feet of water ; tonnage only 

 1000 tons. She was built from the designs of Mr. J. B. Winter, 

 engineer to the Council of India, and was taken to pieces to be 

 shipped for Kurrachee, at the mouth of the Indus. 



STEAM BAMS.* 



Admiral Sartorius, in a communication to the Times, writes : — 



As it is clear the iron walls must supersede wooden ones, let us examine 

 which of the two actual arrangements of the former is the most efficient — the 

 steam frigate iron-cased, with the usual mast, yards, and sails, of a liue-of-battle 

 ship, only using her guns ; or the modification of the steam frigate, which also 



• See also Year-Book of Facts, 1860, p. 25. 

 O 



