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MARINE REVIEW. 9 When it is considered that the above strains change from tension: to compression about ten to twelve times per minute while a vessel passes from the crest to the trough of the wave, it must be recognized that some vessels only survive because they never encounter condi- tions producing such extreme strains. But as there is no certainty that any vessel may not encounter these strains at any time, it may be worth while to consider some improvements in construction herewith submitted, by which, without increasing the weight, nected, by the usual diamond plates, to vertical fore-and-aft stringers, riveted under the ordinary deck beams, and attached to deck plating by intercostals, the entire construction forming a strong and rigid - system of framing, connecting the two sides for united action against al] strains, however complex they may be. The calculations of this section give the following results: ieee Full area of section square inches _ Effective area (for hogging strains) . ...1537.2 square inches ee ee er superior strength and rigidity of construction may be obtained. Neutral axis above base line............ 11.6 feet Fig. 2 is asection of a vessel of exactly the same size as the Sir Neutral axis below top member......... 16.7 feet fs Ge Uy fi . Js ! apbat we see wee ote . edie 5 econ es EMBs oe . a £4 ki vibes l Flatgs Plat 24>. ~ Flange Plete 4%, terete Le Lea gg . ~ 24 Card Brame, J2fh rt -- 2 dann. Denbbing Ane t : = Gh +35 + Ye ~ ao UP pape n 2 tien ae 5 a \ gq 'J y? 7 a" hb | pee ~~ & Que : [eed 3% ( 1 | x 4 é vers Se 5 "tb a ec ede : beet 7 Led beta ie J nN) cee usa| 12° Blane. Ch pats, : TH wih) OE 7 pest Bee | A | wp L [ah rebpeonee. 0 bb 7\e g ( ugloe IA 1 | 2 gs At! 4 ep {Ib | joel i| , Heese ( . i | : 5 ; "hoe | 'X- * fh e fll Oo +: ' 4 : | aa / 7 x : 4 | (es) ais | : ' ars i . sige . +>" : ; | qi ral +5 Me age 'It , i \ adage? + se | ye ali aa ; a9 cae aes \ fw '\s qi - te an Sle FIG. 2. MIDSHIP SECTION OF LAKE FREIGHT STEAMER WITH DEEP GIRDER. Length on keel, 412 feet; beam, molded, 48 feet; depth, molded, 28 feet. : Henry Bessemer, showing additional material at the top in the form - Moment of inertia of section HES ROS 200,177 foot inches of shelf plates, riveted under the beams. These not only give the re- Displacements and bending moments same as for Figure - : quired increase in material in the top members of the structure, but 1d foo dee heen ieee soe Stans nor eciameincl also give additional bracing to the deck frame, securing the same 200,17 : oe against racking strains, etc. The usual belt frames are fitted, to obtain g feu bobian yee ionic ans a good stiffening of the sides, but a further increase in the same direc- 200,177 fie tion is secured by fitting extra deep girder frames, spaced 32 feet, iS tect dente: Chain oneior: os 6.96 tons per square inch thus having two ordinary belt frames between them. To obtain a ' 200,1 " jos better connection of the two sides, these extra strong girder frames ' aie an noua 82,400X11.6 _ 4,775 tons per spans dant. are combined with extra deep deck beams, which are also firmly con- - : ; ' are nee 200,177