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Isherwood System of Construction r j MHE plan herewith shows details of riveting in shift of butts. Fig. 1 shows the completed gir- der before the abaft transverses No. 9 and No. 13. The keel plate No. 4 and center keelson plate No. 3 are shown on this detail as well as part of rider plates No. 2 and 3. The floors are omitted and only the flanges of the angles to the plates are here shown. The keel angles are joggled over the butt straps of the keel plate and the top keelson angles joggled over the rider plate straps. The center plate butt is lapped and has three rows of rivets 34 inch diame- ter as shown at No. 12 watertight floor on Fig. 3. The rider plate has also three rows of 34 in. diameter rivets but has straps underneath. Fig. 3 shows the underside of the rider plate. The keel plate butts are strapped with *This is the fourteenth of a series of articles on the Isherwood system of construction which began in the September, 1912, issue of Tue Marine Review. The first article dealt with the general specifications of the steamer, the second with the sheer, half-breadth and body plans; the third explained the method of getting the sheer; the fourth dealt with the longitudinal and transverse framing; the fifth with offsets; the sixth with the shell plating; the seventh with the shell plating expansion; the eighth with the arrangement of plates and angles forming the spar deck; the ninth with the transverses; the tenth with bulk head construction; the eleventh with the connection of longitudinal frames to the bulkheads and transverses; the twelfth showed the interior framing between the tank top and spar deck ; the thirteenth showed the amount of work that can be put together in a Great Lakes ship yard in a few hours. bez Fie.y The Plan Herewith Shows Details of Riveting in Shifts of Butts four rows of % inch rivets, as shown im Pigs 2: In shifting the butts clear of one another the distance is governed by the number of rivets with a value equal to the material of the whole girder through the line of rivet holes at water- tight floor No. 12. In the last article it was shown that the strength of the center girder through the line of rivet holes at watertight floor No. 12 was 1,340.43 tons. If the rivets were all the same diameter then the strength of a rivet divided into 1,340.43 would give the By Robert Curr number of rivets necessary in the dif- ferent pieces. This cannot be done and every piece has to be treated separately. The plates and angles are tested at the makers at 28 tons per square inch and by punching the materials the strength is reduced to 26 tons. The rivet materials are also tested at the makers at 28 tons per square inch but are figured out at the same strength as the punched materials. The center girder under consideration we have two sizes of rivets 7% inch diameter in the keel and keel angles and the balance 34 inch diameter. keel Ana.@s ovER PLATE Burrs B STRAKE . nad -- Ze weir voiKs nepal eine. eeamn) sees ates eet ct a ' -- --_--_ ©0O0GQO0O000 inp 000910600 |! KEEL PLATE Burr| | Svea \ ' i | WERE AN RO ee A ©000l0000 O000|l0000 ©000!I0000 C000'0000 200000000 ae ro Ol o A Keat Angeet j pP.5 lo 6 oo! Keee Angie? 0000,0000 | oo 0,90 KEEL PLATE Eo pecee © ©C000f0000 ©00G/0 0:0 0 re be /3