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Apply Channel Steel System in Great Lakes Freighter HE first application of the chan- nel steel system of construction in large vessels, was made this spring, when the Pittsburgh Steam- ship Co., Cleveland, installed three channel steel cargo hold bulkheads, in the steamers JAMES J. HILL, RENSEL- LEAR and HARVARD. The work on the steamers JAMES J. HILL and RENSEL- LEAR was done by the Pennsylvania and Lake Erie Dock Co., at Fairport, O., and the work on HARVARD was done by the Pittsburgh and Conneaut Dock Co., Conneaut, O. These companies are subsidiaries of the United States Steel Corp., and during the winter months when the navigation season is closed on the lakes, they do consider- able repair work on the vessels of the Pittsburgh Steamship Co., which owns and operates the largest fleet of ves- sels under the American flag. The new channel bulkheads installed in these vessels are shown in the ac- companying illustrations. They are set up on a slight angle and all are located about 18 feet aft of the col- lision bulkhead, and they serve to block off the cargo hold forward un- der the main deck, thus keeping the cargo back and within easy reach of the unloading rigs. The bottoms of the bulkheads are about 3 feet forward of the No. 1 hatch coaming and they will thus be subjected to considerable abuse from the unloading rigs. BY WILFORD G. BARTENFELD The bulkheads are about 14 feet in height, 30 feet in width at the tank top, and 32 feet in width at the top. The top of the bulkhead is riveted to one of the main deck channel beams, by means of a 10-inch 20-pound plate. At the bottom and sides the bulkheads are connected to the tank top and side tanks with a bounding angle bar, in the usual manner. Twen- ty-five 15-inch 33.9-pound structural. steel channels make up one bulkhead, and as the bulkhead is non-watertight the rivet pitch on the channel flanges is 6 inches between centers. No calking is used in the seams. On future work of this nature a rivet pitch of probably 9 inches will be used. The bulkheads have _ one athwartship stringer channel, with four channel braces bracketed to the chan= nel flanges and to the stringer. This stringer is located about 6 feet above the tank top floor where the bulkhead is most liable to be struck by the un- loading rigs. There are also a few bottom bracket plates spaced about 4 feet, connecting the channel flanges to the tank top plating. There is also a bracket connection to each side tank, at the ends of the channel stringer. There are no brackets at the top or side connections of the bulkheads. In so far as the writer knows, these are the first installations in which there has been a complete eli- mination of frames and nearly a com- plete elimination of all rivets through the bulkhead surface. The only rivets penetrating the face of the bulkhead are at the bounding angles. Of course the channel flanges are the substitutes for the stiffening angle, and in com-. parison with an ordinary plate and angle construction, the channel bulk- heads have about three times as many flanges as there would be angles in the plate .construction, thus giving the bulkhead shell three times as much stiffness, as in the plate construction. There were a number of unique features brought out in the fabrication and erection of these bulkheads. The Pennsylvania & Lake Erie Dock Co. drilled the flanges of the channels, rather than punching them. The channels were placed on their flanges and all grouped together. A templet for the spacing of the holes was laid down, and the flanges marked for drilling. The drill of vertical high- speed electric type furnished by the Van Dorn Electric Tool Co., Cleve- land, was mounted on a_ two-wheel drill buggy, such as is used for countersinking and reaming in plate tank tops. This is a one-man rig, and all the flanges in the entire bulk- head were drilled in 2 days, that is in 16 hours labor by one man. If the channels had been punched, it would have required three men, to put the INSTALLING CHANNEL STEEL BULKHEAD IN STEAMER RENSELLEAR OF THE PITTSBURGH STEAMSHIP CO.—AT LEFT— CHAN- NELS ASSEMBLED AND RIVETED TOGETHER IN TWO SECTIONS IN HOLD OF THE VESSEL—ONE SECTION BEING HOIST- ED INTO POSITION—AT RIGHT—COMPLETED BULKHEAD IN PLACE WITH BOUNDING ANGLES TO TANK TOP AND SIDE TANKS MARINE REVIEW—June, 1927 31