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24 bulkhead unless it is a real bulkhead. Mr. Gatewood mentioned some- 'thing about wing compartments. I think we should go rather slowly with reference to wing compartments. It is a question in my mind whether a wing compartment is of great value. It forms a second line of defense, but unless there is some means adopted to connect the wing compartment to the corresponding wing compartment on the other side of the ship, they may prove a positive danger, that is, the vessel may lose her transverse sta- bility sufficiently to capsize, so that the longitudinal bulkhead is not, in my opinion, an added means of prevention of sinking, unless it is kept rather close to the ship's side itself. J. G. Tawresey:--Both of these pa- pers are by gentlemen who can speak with authority on the subject. There is one rather unusual circumstance in connection with the preparation of -Mr. Dickie's paper, that should make it of special value to the society, and that is that the paper was actually written at sea where the conditions and the limitations, especially the lim- itations, are very real, more so than they are on the blue prints stretched on the drafting board. Mr. Dickie's long experience of a life time spent in designing and building ships, spent on both warships and merchant ships, qualified him to observe these condi- tions. ; I note that, perhaps leaving out some of the details, the broad con- clusions in the paper are somewhat identical, and both of the writers seem to take the view that has been taken in the navy, that the effort should be to make the ship herself safe rather than to depend on boats, and the methods adopted are practically the only ones that can be adopted, namely, subdivision bulkheads, double bottom, and by cellular compartments at the waterline. In some ships in the navy, they are confined more to the com- partments at the side of the vessel, whereas Mr. Dickie's paper seems to divide the whole space between the decks into small compartments. Center Line Passage We also note the reappearance of the center line passage, Mr. Dickie's favorite center line passage, except in this case he moves it higher up. The question is--can the usages in commercial practice be modified to make a ship of this character satis- factory to the owners and to make it financially successful? I am rather surprised to find a man who has been so intimately connected with the mer- chant service proposing to Sacrifice, unless he can find some way of using it which does not appear to me, so THE MARINE REVIEW much space to protect the ship's buoy- ancy and stability. He has gone quite as far as a naval architect goes in designing a war vessel. D. W. Taylor:--I did not propose to mingle much in this discussion, but in reading Mr. Dickie's paper there was one thing which puzzled me very much. It may be a clerical error. You will observe in his plate he gives the longitudinal section of the ship, and that deck which slopes down at each end he calls throughout the upper deck. I was. aware in the mysterious system adopted by the Classification Society that the upper deck was never the highest deck, but did not know that it had gotten into the hold yet, and I am wondering whether there is not a possibility of some confusion as regards that mat- ter. Horizontal Watertight Compartments I observe that Mr. Dickie's ten- dencies run largely to horizontal wa- ter-tight compartments. Apparently Mr. Gatewood scorns water-tightness, it would "appear: am slad~ Mr. Dickie has come forward with a de- sign in which he relies so much upon the horizontal watertight compart- ments, because I several times advo- cated in the past in some of these very large vessels the fitting of a wa- tertight deck forward and aft. of the great dangers is the pronounced change of trim, and if in any way you can confine the water horizontal- ly, the change of trim is reduced. You avoid the necessity of putting water in aft at times. I have been met by the statement that it is not commercially possible to equip water- tight decks. It would seem to me with these large liners, these very large vessels, there is in the neighbor- hood of the water line an actual line of demarcation between the inhabited part of the vessel and the part of the vessel devoted to cargo principally, and it should be possible to make that line of demarcation watertight and to pro- tect the integrity of the watertight deck by enclosures running up above the bulkhead line. I hope Mr. Gate- wood will give that matter attention after consideration of Mr. Dickie's paper. Mr. Dickie has spent his life- time in commercial work, and he would not advocate so large a_ hori- zontal watertight subdivision unless he believed it commercially practicable. Aldin D. Welds:--There is one point E would like to raise--I do not know whether it has been brought out in this paper or not--and that is in con- nection with the protection against fire by the use of flue gases in the boiler. I believe this question has come up before the Naval Architects One| , : January, 1914 of Great Britain. of the donkey boiler can be used, and, therefore, there is protection always at hand. At sea the funnel of the main boilers would be tapped, and the equipment in the Harbor system, which is the British system,--patent- ed for this service, consists of a De Laval turbine driving a fan, and there is a washer which uses sea water for cleansing the gases. The flue gases consist of about 80 per cent of nitro- gen, something like 10 per cent of CO:, and at most 1 per cent of carbon monoxide, a very poisonous element, and about 9 per cent of oxygen, and as it requires 15 per cent oxygen to sup- port combustion, it is an inert gas. One difficulty, perhaps, is that it is so light, being as compared with air ~ about 1.05, but I believe in the navy carbon tetrachloride is used experi- mentally, with some success, and that, I think, is about five times as heavy as air, and, of course, it would be much more fapid, but with the use of a fan I do not see why it could not be blown into the hold as quickly, and being always available as flue gas, you would not be taking any power from the ship, as would be the case if steam were used. Avoiding Watertight Doors Joseph H. Linnard:--I note the state- ment in Mr. Dickie's paper as follows: "There would be 12 bulkheads extend- ing from the inner bottom to the up- - per deck. These would be absolutely watertight, without doors or openings whatever." I think most of us who have been engaged in building ships, especially men of war, know the great desirability of avoiding the use of wa- tertight doors or_ similar openings through bulkheads that are supposed to be watertight. Such watertight doors, even though fitted originally with great accuracy, and when tested found to be in perfect condition, yet in the course of service, where they are apt to be left open for long periods, are found, when the emer- gency comes, to be very unworkable, or if workable, far from watertight, Owing to distortions that have oc- curred and have not been corrected. Therefore, it has seemed to me that if it is feasible, that is a very impor- tant point in fitting the transverse bulkheads particularly, which, as has been remarked this morning, are the main subdivisions that appear practi- cable and to be made without undue expense. But particularly with ref- erence to such transverse subdivisions in the machinery compartment it has been found difficult to preserve such absolute watertightness without any openings fitted with watertight doors. In port the flue 1 oi Ate gla GN aaa rg SON RSE ee eH Ly Mec R oy tks NAR 9 eed gh eA Ge