The following text may have been generated by Optical Character Recognition, with varying degrees of accuracy. Reader beware!

tion of such an improvement to justify the expense has not been given. In the vessel shown in the diagram (Fig. 4), however, there is a very sub- stantial saving of material, leading on the \ | | | "TAE Marine. REVIEW at right angles necessitating a very heavy and expensive riveted attachment, and of which the rivets can only be fitted in after special fairing and drilling. At every deck in the ship this branching pro- \ | | ! FIG. 5---SECTIONAL VIEW OF A STEAMER, SHOWING "HALL" STRINGERLESS SYSTEM OF 66 99 C' FRAMING. whole to a gratifying economy in con- struction, and increased deadweight with reduced tonnage. This system of fram- ing has been well received by owners and their superintendents. _ The transverse system that I have re- ferred to has given at the very best what is relatively a compressible structure lengthways. Those who have experience in ships' repairs, especially consulting en- gineers and superintendents, are well "aware of the compressibility of the up- per structures of vessels by the panting that is evident of the plating between the points of the transverse support. Since the Classification Societies introduced the system of wide spaced pillaring in con- nection with the girders riveted to the decks, a good deal has been done by build- ers adopting this system towards over- coming the compressibility of the upper structure. These intercostal girders, how- ever, are a serious addition to the number of parts in the structure and contain a large amount of costly riveting, and, while carrying us in the right direction as regards strength, take us further from simplicity. From the very shape of the close- spaced transverse frame, which, commenc- ing in an ordinary cargo vessel with a riveted attachment on the keelson, ad- vances to the bilge with several vertical riveted attachments carrying the inter- costal girders; then at the bilge with an expensive attachment at the margin takes a sharp curve and extends up the side of the vessel, affording riveting attach- ment to the side stringers; reaches the first beam knee and sends out a branch cess must be repeated until it arrives at the upper deck, when the frame, with an- other similar riveted attachment, turns at right angles across the deck. Exactly the same number of turns, branches and riveted attachments are repeated on the opposite side of the vessel. This circuit- ous transverse frame must be pillared either by one, two, or three rows of pil- lars, and we must either put a pillar on 27 weight is worked up in these transverse members, for a large part in riveted at- tachments, which are a source of weak- ness rather than strength, and not a pound of which can be called upon to do ser- vice in the direction in which the most serious strains affecting a ship must be met. I wish now to say one word more in regard to the value of longitudinal ma- terial in transverse-framed vessels. I un- derstand that Classification Societies and naval architects generally, in calculating the longitudinal strength of vessels, as- sume that when the upper works are un- der compression, and a vessel undergoing sagging stresses (I am paying particular attention to the upper works, as herein most failures have been experienced), the value of the plating between the beams is reckoned as able to withstand a some- what higher stress than experience teaches the material is able in order to provide a factor of safety of about 3 to 1 with a dead load. From recent causes of collapse of decks, it has been admitted that the plating between the beams has buckled under stresses of probably 12 to , 14 tons, according to thickness. This as- sumed factor of safety, I fear, therefore, in transverse-framed vessels, is in ordin- ary cases non-existent, besides which it is a question whether it is safe to assume such strains as dead loads. For a number of years my firm has been in the habit of fitting some longitudinal framing under- neath the midship portion of the upper- most deck in all vessels, and, in every vessel of extreme proportions, have adopt- a en ee a aan | | -- Sf " VO, o o a et c 1 ric. 6. every beam or collect the beams in groups by means of strong riveted girders, in order to open out the pillaring. It is dif- ficult to conceive, without the minutest study in detail, what a mass of useless ed the longitudinal girders on all decks to insure increased longitudinal strength. I think I need say no more to convince my hearers what my attitude has been for some years towards the ordinary