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16 - Altogether the problem appears to be one of serious aspect for the west- -ermers and they are preparing a vig- = orous voicing of their wrongs through the press, to their representatives at the seat of government, and through the 'various commercial bodies, in an effort to obtain a revision of the ruling whereby it will 'be possible to continue this valuable traffic. -LAKE SHIP YARD METHODS OF "STEEL SHIP CONSTRUC- TION. BY ROBERT CURR. Fig. 26 shows completed plan of part of the spar deck. This plan takes in two outer string- ers A A, one inner stringer B, contin- uous seam: strap C, outer stringer double butt strap D, inner stringer -double butt strap E, stringer angle F, and hatch coaming G, all of which add ito the longitudinal strength of the vessel. The stringer plates, outer and inner, are 24' x 60"'x 1"; stringer angle, 6" x 6" x %"; hatch coaming channel 12" x 7/16"; butt straps outer stringer ortom,§ 11/16": 'batt = strap. outer stinger top, 12/16"; butt strap inner stringer bottom, 11/16"; butt strap in- 'ner 'stringer top, 12/16", all of which will. be considered in the following "example. _ The shift of butts are so arranged that they are three frame spaces apart equal to nine (9) feet between stringer butts on the alternating butts. The continuous seam strap butts THE MARINE KEVIEW come two frame spaces apart from the stringer plate butts and is equal to six (6) feet. This is considered a good shift of butts and nothing less should 'be adopted in any case through- out the ship. Fig. 27 shows a cross section of the stringer plating and the parts to be considered in the following ex- ample. ' Fig. 28 shows the riveting of these parts illustrated in. Figs. 26 and 27. This sketch shows the nine (9) feet shift of stringer plate butts between the two stringers, the after end of outer stringer No, 12 and fore end of inner stringer No. 12, The unavoidable weakest section of ® & 3 4 s 4 e = Ss x S$ ET. x 0 5 For'o eres eatee [te xe. oC te eS SS ae aw Ot ae Oe i to ae tals As lect) WA iB) yf NA ley Ni = ih hy it F t 1a ti ote SS i 1 A " it oe ' ul " " 7G. 26, Le W = A -- oe ee at ae ee ee aoe aes ae SS ome em eee ee e the stringer plating is shown through -- beam rivet holes X X. The solid material through the beam X X amounts to 120 inches. The material through the line X X when punched amounts to 99.82 square inches. This reduction is caused by punching of 17 rivet holes. The rivet holes being countersunk increases the size of the hole. Fig. 29 shows a sketch of the rivet hole after being countersunk, the size is taken at half the thickness of the plate being 1 3/16 in diameter. The punched - rivet hole is 15/16 inches and when countersunk is 1 6/16 inches, making 1 3/16 inches in the middle of the plate as shown by sketch, 99.82. x<- 26 2595.32 tons the unavoidable weakest section of the two spar deck stringer plates. The butts have double butt straps and gives the one-inch rivets a value equal to 36 tons per rivet. The value of the riveted butt for one plate amounts to 46 X 36 = 1646 tons. 1646 X 2 = 3292 tons, being 696.68 tons stronger than through the -- line of punched plate X X, : The butt thicknesses have to be con- sidered in this example, which are of importance here and' must have an area of section equal to the stringer plating XX. The outer stringer A A has an area of section of half the width of the Stringer plating X° X and" is equal to 1297.66 tons. : The strap on the under side of the butt D is 11/16" thick by 60 inches wide. 60" -- 9 rivet holes equals 50.44 inches. 50.44 X 11/16 = 34.68 square inches. The top strap is 42 inches | wide by 12/16 inches thick. 42" -- 125° for (rivet "holes equals 31.75: oi¢s * 12/16 = 23.31 square inches. the