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The Marine REVIEW April, 1909 Column No. 4 shows the number of rivets punched as per Figs, 47 ang 48. y Column No. 5 shows the diameter. of the rivets after 'being countersunk, : mM f ee eeee | Mit Z| i L poo | A ' Se Pe & fe Fe 7 i IG Kt ks HL | J 4 ° 2 | 7 . aN 1 7. eo as Loa 4 ae H 2 cv a A "lq wi w 7 ma vA , q\X : F : aR Sin area a oe ee Se - Wh = : e - B = Re 68 The materials affected are keel by the close punching of the materials plates, center keelson plate, shell plat- moe Bf, Deo ol K and 1, longitudinal girder plates, tank top Dating A. by Cc, 0, FE, F, G, and tankside top plating. The accompanying table shows the dif- ference in the area of section caused for watertight work. Column No. 1 shows the area of section of tthe punched material taken from the ta- ble explanatory: of Fig. 42. Column No. 2 shows tthe sizes of material from the same table, as does column No. 3 for unpunched materials. CALCULATION FOR NEUTRAL AXIS. 1. 2. 3 4. 5. Distance Scantling Area of section in of CG Items-- in inches. square inches. above keel. Moment. Mel platen. once ea ie se, 16.63 x 15/16 15.59 0.05 0.77 Piece plate <ancies i 6.25 x 12/16 4.69 0.47 0.79 Stell "plattis Bi. 69.36 x 11/16 48.00 0.15 7.20 Shell splating © and D..... 0.60: 141 x 10/16 88.12 0.20 17.62 Ohl pie Ege. 53.50 x 12/16 40,12 0.70 28.08 % center 'keélson =~. 2 4. 51 97/32 14.34 2.70 33.7 I Girder angles 23s 16 & 6/16 6.00 1.80 10.80 Girder plate 9... Ae, aay, 123 x 6/16: 46.12 3.50 161.42 Shell plating. Ges aie ee < 60 x 8/16 40.20 5.00 201.00 Tank. top plating A, B, C and D.. 209 x 8/16 104.50 5.14 537.14 Center -keelson 'angie 772.0... 5.50x 8/16 2.75 5.20 14.30 Bilge stringer sy go 7.00x 7/16 3.05 5.30 16.16 Tank side; strake, Boo os 53.50 x 12/16 40.12 7.30 292.87 Shell plating Ea ris. 58.75 x 10/16 36.09 9.40 339.24 mine stinger No. Vi ot00% 5.56, 23. 16.78 x 7/16 7.34 10.10 74.13 ae SG ay a ee, Yor 6/16 27.00 14.00 378.00 SMe gatas Ti 61.88 x 10/16 38.67 14.80 572.30 Side stringer No. 2.7.) 16.78 x 7/16 7.34 15.20 111.56 Tank side Ge eer oe 1) x 6/16 13.87 19.00 263.53 mire: Olating Ko 56.50 x 11/16 38.84 19.70 765.14 Tank side:top angles. 2.0.40... 7.50x 8/16 6:75 20.70 77.62 Tank. side, top pistes) 0.5. .00.5 7 por oe 9/16 30.93 20.80 643.34 uel platigg ba: 51.88 x 15/16 48.60 24.80 1,205.28 Side stringer No g.....00 3 16.78x 7/16 7.34 25.40 186.43 Shell jecame sleayy 0S, 19.50 x 1 19.50 27.50 536.25 Shell plating Ma a: 45.10 x 15/16 42.28 29.90 1,264.17 phannel pirders 33.56x 7/16 14.68 30.60 "449.20 Spar deck angle Meee to ey ek. O70 e718 8.25 31.40 267.52 Spar deck BUN er es es 120.30 x1 120.30 31.60 3,801.48 Fetch cbaining £2050... / i x 7/16 6.50 32.40 "210.60 925.15 bre 12,474.64 Neutral axis above keel = 13.48 feet Column No. 6 shows the amount of material there is in the punched holes which thas to be deducted from the unpunched material. Column No. 7 shows the actual size and thickness of the material after de- ducting for punching. Column No. 8 shows the area of. punching material at the bulkhead. The material for the section through the watertight bulkhead column No. 8, amounts to 618.94 sq. in. and has a value of 24 tons per sq. in. 618.94 K 24= 14,854.56 tons. Column No. 1 shows the same ma- terials with an eight diameter spacing of rivets with a value of 26 tons per sq. in. equaling 681.54 X 26=17,720.04 tons. 17,720.04 -- 14,854.56 = 2,865.48 which must be made up, in order to maintain the strength of the vessel and make it equal to section through line of holes at No. 6 web frame. Fig. 47 shows an arrangement of doubling the outside strakes of plat- ing on the watertight bulkhead frame in order to overcome the reduction in materials by punching for water- tightness. In the arrangement shown on Fig. 47, the doubling plates have an area of 187.81 sq. in. with a value of 24 tons per sq. in. equaling 4,507.04 tons. This exceeds the reduction by punch- ing to the extent of 1,734.40. The number of rivets must not be 2,865.48 less than --_----_-_=191, which ae shown on Fig. 47. Example: 168 X 15==2,520. 14 X 26364. 2,520 oe = 2,884 tons strength of rivets. In the arrangement of rivets care must be taken to not have more in a line than are shown on Fig. 43. The rivets should be arranged about eight diameters, measuring from cen- ter to center of the holes, inside of the outside edge of the doubling and the frame angle holes. Fig.. 49 shows midship section of a vessel showing the structural material embraced in the equivalent girder and dealt with in the calculation for the neutral axis and moment of inertia, see Fig. 42. The table showing calculation for neutral axis has the items for longt tudinal girder in first column, scant- ling for punched material in second column, area of section in sq. im. im third column, distance of center of. gravity above underside of keel plate