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MARINE REVIKW. ; II Longitudinal Framed Steel Tug. The midship section and outboard plans of a tug illustrated here- with were made some time ago by Robert Curr of Cleveland, and Robert Clark, now of San Francisco, for the L, P. & J. A. Smith Co. of Cleveland. Dimensions of the vessel are 91 feet over all, 22 feet beam and 12 feet 6 inches depth. The longitudinal frames run from stem to stern and there are a sufficient number of transverse frames to keep the vessel in ship-shape crosswise. The longitudinal frames are cut at the transverse bulkheads and bracketed to same with a number of rivets equal to the frame section, thus making a connection equal to a continuous frame. Shell plating is so arranged that. the strakes may be ordered of a width equal to the distance between frames and the lapping on same. By this arangement the builder would be enabled to keep the outside plating fair without the trouble and ex- pense usually experienced with light plated vessels. Very little fair- ing up on the floor would be needed, according to this method, as the 'shape of the longitudinal frame can be obtained from the plan from a very small scale. The longitudinal frames would need no furnacing, as they stand at right angles to the shell plating and any curve length- wise could be gotten in at the cold press. The beams are transverse and the deck plating is lapped on them with a view to preventing buckling in the light plates. Deck stringers are arranged to overlap at the ends over the coal scuttles, the lap being of a diamond shape and made large enough to secure an arrangement of riveting that will result in a proper connection and at the same time form a doub- ling to compensate for cutting the hole for the scuttle. Bunker bulk- heads are of steel and also the shovelling flat, which extends from the fore end of the boiler room to the after end of the engine room, The deck house and pilot house are of steel, the windows being arranged similar to those of the tug L. P. Smith of Cleveland. According to these plans the stem and stern post are done away with, the plates be- ign simply riveted together anda saving of considerable material there by effected. The entire design of the vessel represents an effort to _ avoid excessive weight and extra labor in construction, and to secure, at the same time, a tug suited to lake work. Robert Curr, who designed and built two or three tugs for the firm of L..P. & J. A. Smith, and who has just returned from West Superior, where he represented Pickands, Mather & Co. of Cleveland in the building' of the steel barge Constitution, is about to undertake Survey work or to represent vessel owners in their dealings with ship builders, whether on repairs or the building of new vessels. He has been connected with lake ship yards at West Superior and Cleveland for several years past,and before coming to this country had a thorough training at the famous vorks of the Thomsons in Scotland and that of Harland & Wolff in Belfast, Ireland. He may be reached by mail at the Perry-Payne building or through telephone 472. The King Bridge Co. of Cleveland is building for the Craig Ship Building Co. of Toledo one of their new and improved 5-ton pneumatic traveling cranes for use in the Toledo ship yard. Unusual Corrosion of Steel Vessels. Soon after the application of steel in the construction of British coasting steamers, with the consequent diminution of thickness allow- able with that highly tenacious material, it was found that the forward part of the bottom of these vessels, from a few feet before the collision bulkhead to about 10 or 12 feet abaft, became, after a few months work at sea, very much more corroded than elsewhere. The countersink points of the rivets were found pitted, the rivets sometimes were loose, and the shell plating was so much set in between consecutive floors as to suggest that the vessel had been ashore. Associated with this phe- nomenon was a wasting of the lower edges of the outer strakes of plat- ing at the same part of the bottom, and this wasting proceeded at such a rapid rate that, after two or three years service, it had extended to the rivets in the lap of the plate edges. Considered by itself, the set- ting in of the plating betwee. the floors and the loosening of the rivets attaching it to the frames, seemed to point to a straining effect due to the weight of the large body of water carried in the fore-peak tank for trimming purposes when steaming without cargo. Measures were at once taken for reducing the depth of the fore-peak tank, and for affording a stronger connection between the peak bulkhead and the hull of the vessel. - But, despite continued efforts in both directions the mischief still went on, until the wasting of the plate edges and the corrosion of the rivets suggested that som:> other cause was at -- work than had at first been suspected. It was ultimately discovered that the principal cause of the phe- fete mt Sa = - THewee aa os ees = -- i NNN 5 Cee emer or it | = | Wek || ' , ' \ | ---- : + J | CLL ITok SECTIONS < Sree Tus ( aia = Set Aa re Pena ef eile Combat Anuar af Sata B6| 0 nomenon was the violent pitching movement of the wodiol when driven head to sea in a light condition. For, with the machinery right aft, the vessel necessarily trims by the stern, even with the fore-peak filled with water. Whether the tank be hin or small, tie pitching motion, when driving head to sea, is a frequent one, and the forward immer- sion being but small, it follows that the comparatively bluff bow re- peatedly rises and falls with a thump on the approaching sea. The relatively thin steel plating was thus, in the course of time, set in be- tween consecutive floors, while the atmospheric air imprisoned between the "luff of the bow" and the sea at. every plunge, acted corrosively upon the surface of the plating and the countersunk points of the rivets, and the lower landing edges of the outer strakes, in the same way as it does upon the forward upper edge of a screw propeller. blade. When once the cause of the mischief was discovered, a remedy was speedily found in stiffening and thickening the framing and plat- ing sufficiently to stop the vibratory movement that had loosened the rivets, and to allow a deeper and better countersink for those rivets. Moreover, the imprisonment of air bubbles at the landings, with the consequent wasting by corrosion, was prevented, and the evil was cured. 'The plating still rusts more readily there than elsewhere, but this is remedied by frequent painting.--J. 8. P. Thearle in Cassier's Magazine. The navy department is furnishing prospective bidders with plans and specifications for the model tank that is to be constructed at the Washington Nayy Yard.