Page:Popular Science Monthly Volume 91.djvu/707

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Popular Science Monthly

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��immediately adjacent on each side. The five steel castings consist of one extending clear across the vessel at the bottom and forming the inner bottom for water ballast or-f uel oil ; two identical side castings, each extending from the top of the double- bottom unit to the upper deck, and two cast-steel deck - beam sec- tions, one for each deck. The six welds in each transverse sec- tion are made be- tween the two deck beams and the vertical side casting and be-' tween it and the double-bottom on each side, giv- ing three welds to each of the trans- verse sections, a total of six in each of the five castings. , The thirty-foot ship side castings and the fifty-five-foot double-bottom unit may seem unwieldy, but equally large and more diffi- cult castings, such as battleship stem

���Examples of Electric Welding Note the V-shaped groove cut in the rectangular piece in the foreground. Note also in the piece of steel in the left back- ground, how the roughness of the weld may be ground off so that the position of the welded place will not be noticeable

��pieces, rudder posts, etc., have been success- fully turned out for many years past. Cast steel has driven out the riveted forms of locomotive tender bed-frames, car truck frames, vestibule ends for steel cars and Pull- man coaches, etc., where excessive vibration has caused the rivets to loosen and where abnor- mal strains, such as must be en- countered by ships in a heavy sea, have bent the rolled steel frames and necessitated costly repairs and overhauling.

The cast-steel ship will have no rivets, liners, lap or butt joints in the shell-plating, bulkheads, double bottoms,

��etc., and no frames, reverse frames or the usual great number of angle irons and brackets which go to make up the ordinary fabricated ship. Some of the weight of these various parts will be used to increase

���Castinqs Solid centerline

��'Longitudinal weld transverse weld on each side of one section

��ate^" Midway solid-' Nntermediate open stiffeners shown cut Sstinqstiffener oSffeners casting It.ffener off close to solid transverse member

A Perspective Transverse Cross-Section of the Cast-Iron Ship

The five major castings from which the srflp will be made are the double-bottom casting, the two vertical side castings, one on either side, and the two cast-iron deck sections. Note the strengthening ribs in the side castings, somewhat similar to those used in the longitudinal method of ship construction, and the manner in which the rolled plates welded on the top of the double-bottom and deck sections are employed to provide thoroughly water-tight floors

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