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THe Marine REVIEW Naval Architects and Marine Engineers. Mr. W. Carlile Wallace's paper en- titled "Some Recent Inventions as Ap- plied to Modern Steamships," was the concluding paper of the first day's ses- sion of the Society of Naval Archi- tects and Marine Engineers. Its text was as follows: It is 12 months almost to a day since the Mauretania, the second of the big Cunarders, sailed into the port of New York. At that time the thoughts of the whole matine world were centered on these two vessels, and speculation was rife as to whether they would be able to fulfill their speed guarantee, a few engineers on this side of the water being kind enough to state that the Lusitania had achieved her utmost on her maiden voyage. As the representative of the build- ers of this vessel I am extremely pleased that these gentlemen have turned out to be false prophets, as I was always satisfied they would. lI am also satisfied that when the Maure- tania again heads for this side, and settles down to work, she will give an equally good account of herself. | In vessels of the Lusitania class, speed is not the only desideratum; safety and comfort are now looked upon by passengers as two very im- portant factors in enabling them to decide on which vessel they will book their passage. From this point of view it will not, I think, be out of place to lay before this society a few par- ticulars of some more or less recent inventions, which I believe tend to- wards the attainment of these re- quirements. The Lusitania and Mauretania, as no doubt my hearers are aware, have the most complete system of water-tight compartments of any ves- sel afloat, and they would float quite safely with any two of the main com- partments full, a condition possible if a collision carried away one of the transverse bulkheads. In addition to the cross bulkheads the vessels are further protected by the two fore- and-aft bulkheads forming the high- pressure turbine rooms and the mak- ing of the coal bunker sides water- tight forward from the engine room for 100. frame spaces, so that were the bulkheads without opening of any kind below the main decks the ves- sel would be practically unsinkable. The idea of building vessels without doors in the bulkheads has been adopted by one at least of the trans- Atlantic companies, but an attempt to follow out this plan on the new Cunarders would make them absolute- ly unworkable as there are three trans- verse and two fore-and-aft bulkheads dividing up the engine space proper, and four transverse bulkheads in the boiler space counting the one next the engine room, not to mention the bunker sides at all. The next best thing to having no doors in the bulkhead is to provide a means by which every bulkhead door in the vessel can be closed' from the bridge in a matter of a com- paratively few seconds, either in very thick weather, when a collision is imminent, or after a collision has oc- curred. For the safety of the crew and for the convenience in working the vessel, any arrangement for doing this must possess the following quali- fication. First, it must be possible under ordinary conditions at sea or in port to open and close the doors at will, leaving them either open or shut, as may be required for the conveni- ence of the working staff. Second, before the doors are closed from the bridge an automatic warning must be given to those below that the doors are about to close, when they must close slowly, but surely, not drop sud- denly, as this might result in a seri- ous accident: Third; after the. doors 'are closed from the bridge it must be possible to open any individual door to allow the escape of an imprisoned man, the door closing automatically after his release. Fourth, in the event of water entering any compart- ment to a dangerous extent, the doors not having been closed from the bridge, the doors in immediate proximity to this compartment must close auto- 'maticaly, shutting it off from the rest of the vessel. And last, the means adopted for closing the doors must be such that even when the mechan- ism is submerged it will still perform its work. Four mediums are availa- ble for doing this work--steam, air, water and electricity. Steam is inadmissable for several reasons, the principal one being that in the event of a steam pipe bursting through a collision or otherwise, it would become a menace to life rather than a life-saving appliance. pneumatic system has been tried and found wanting, to say nothing of its being too expensive, so it may be set aside. Electricity has been used with con- siderable success in this country, The but has objections, which appear to the writer to relegate it to the sec- ond place as a means for opening water-tight doors. Among them may be mentioned the possibility of blow- out of fuses or injury to the motors actuating the doors, through over- load, the risk of short circuit should the gear for actuating the door or the conductors become submerged, and the great difficulty of locating or remedying a fault in the system if the conductors are protected as they should. For these reasons hydraulic control seems to fulfill, more nearly than any other, the requirements ne- cessary to a thoroughly reliable water- tight door-closing system. The doors of the two large Cunard- ers, also in the Carmania and Coronia, are actuated by means of a hydraulic system, which has been carefully worked out and embodies in the full- est possible manner all the require- ments as already set forth. Plate 1 shows the system as ap- plied to the Lusitania, the arrange- ment in the Mauretania being identical, with the exception of the position of the pressure pumps and possibly some minor details. The pumps are supplied with steam from the main boilers, and are two in number, of the duplex double-act- ing type capable of maintaining a pressure of 700 pounds per square inch throughout the hydraulic mains. Both pumps normally are under steam but either of them are of sufficient capacity to close the whole 36 water- tight doors in the vessel in from 15 to 20 seconds when making 40 strokes per minute. Steam accumulators were fitted in the earlier installations, but as these were found to be clumsy, expensive, and inconvenient, they have been dispensed with in the new Cunarders and other recent vessels, the pumps being so proportioned that immedi- ately on their receiving steam they get away at once at full speed, the supply of steam being regulated by a hydraulic governor so_ sensitive, that the moment there is a call made on the mains, whether due to open- ing or closing a single door or clos- ing all the doors, the slight fall in pressure starts the pump away and maintains a steady pressure of 700 pounds on the mains, whether the pumps are only just moving to sup- ply any small leaks or slip or when they are running full speed, closing all the doors.