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co : MARINE REVIEW [November 23, faster. All that is necessary, therefore, in the operation of this machine is to see to it that the speed of transit is in excess of double the speed at which the two boats come together. "After the load is dumped at the warship the operator of the engine releases the friction lever on the 4,000-pound drum, thus reducing the tension on the lower part to some point considerably below 3,000 pounds, whereupon the 3,000-pound drum acts to haul in rope, and thus returns the carriage to the collier. The speed of conveying is about 1,000 per minute, - consequently the load will be taken from the collier and deposited in the warship in about twenty seconds. Attention is called to the fact that the total tension on these two parts of rope will never exceed, say, 8,000 pounds; furthermore, should the ships pull away from each other and the tow-line part, the only effect will be to unwind the rope from one of the drums, its end falling into the water, whereupon the other drum will wind in the other end of the rope and recover the carriage attached thereto. The drum used for operating the conveyer also serves to wind up and store the cable when the collier is not coaling at sea." DISOUSSION OF ADMIRAL MELVILLE'S PAPER. In the absence of Rear Admiral George W. Melville his paper on "Causes for the Adoption of Water Tube Boilers in the United States Navy" was read by W. M. McFarland, formerly one of the loyal sup- porters of the engineer-in-chief, while connected with the bureau of steam engineering, but now with the Westinghouse companies. Rear Admiral Melville's paper will be found in full elsewhere in this isstie. The dis- cussion was opened by Mr. Horace See, who said: "The paper is one that should not be allowed to pass without 'some- thing more than general comment. The past ten years have been' marked by a development that has given us not only superior material and better facilities, but has also made possible results heretofore unobtainable, so that we are called upon to view the water tube boiler from the new and not from the old standpoint, to consider the one of to-day and not of yesterday. It is perfectly natural that its introduction should meet with opposition to be in keeping with history which shows that the most im- portant improvements have only obtained a foothold after a struggle. Its introduction needs no excuses and its development has been such that we can very safely say to our good old friend, the cylindrical or large water tube, for such it really is, that it must give place to the water tube as did the semi-cylindrical and rectangular to it; as did the side-wheel to the screw propeller; the simple engine to the compound; the jet to the surface condenser; the plain to the piston slide, etc. "Engineering is progressive. It cannot afford to stand still. When it does we must expect decay. It does not follow from this that we must accept every novelty presented, but must, however, take advantage of every real improvement or be content to remain in the same old rut. My acquaintance with the water tube boiler makes me believe that the prin- ciple on which it is founded is sound and that it will bear comparison with the type in general favor. This opinion is based on the fact that the elements entering into the construction of the cylindrical, or inter- nally-fired, large water tube boiler, are more numerous and more dangerous than those entering into its construction; also more difficult, as well as more expensive, to look after and keep in repair. The tube exists in this boiler as well as in the other, subjected to the same causes that produce decay and injury. We have in addition the furnace liable to collapse, the combustion chamber subject to eating away and leaking at all joints, and the immense shell subject to injury at the joints from the unequal expansion and contraction of the thick plates. The tube being the only part considered dangerous in the water tube, I think we may pass this objection if solid-drawn steel tubes, now possible, of proper thickness are used. These tubes, however, must be arranged to perform their duty not only in regard to economy but also as to life and safety. If, however, they are not submerged or so formed or arranged as to prevent the water from coming in close contact with all parts subjected to the hot gases, they will suffer more rapid deterioration or become loosened at the ends. The bulging of the drums of the water tube boilers of the Nashville must not be charged to this type of boiler, as the same thing has happened to all types where the gases have been allowed to come in contact with the metal where steam and not water is against its other side. The change of shape of the drums no doubt may also have had something to do with the leaky tubes. "T believe that a boiler built with straight, submerged tubes, and no part of the steam space exposed to the direct contact of the gases, possesses greater advantages than those enumerated in the paper, whilst the disadvantages are less, and consequently there is no reason why the following is not a correct assumption: First, that the tubes of the water tube boiler will stand the work if solid-drawn and of proper thickness. Second, that the boiler without stays and numerous narrow water spaces difficult of access, and large cylinders liable to collapse, must certainly call for less skill to manage than one with them. Third, that the simple machine must require less skill to manage than the complex. Fourth, that small, simple units with accessibility are not a disadvantage whilst large ones without it should be placed in this class; no one today takes exception to the increased number of units in the steam engine; why should we in the boiler if smaller and safer parts are obtained. Fifth, that steam can be generated only from water, so that the surface below the water level should only be counted for this purpose, and if this is done when the comparison is made with the cylindrical, I believe the heating surface of the one type will be found as effective as that of the other. Sixth, that it is an open question whether the small reserve of water is a disadvantage where high pressures are carried, as the shorter time re- quired to empty and fill, as well as to obtain steam, should be considered in this connection. Seventh, if we take into account the number of plates, rivets, tubes, the different kinds of stays, crown bars and bolts that enter into the construction of a cylindrical boiler, we will undoubtedly find fewer parts in a water tube boiler generating the same amount of steam. Fighth, that the water tube boiler should not be found difficult of access except in case of failure of a tube and then, with the small body of water carried, their plugging or replacement can be quickly done. Ninth, that although we have more tubes, the joints or parts liable to leakage will be less than in the case of the cylindrical. Tenth, that the high pressure of steam carried is a preventative against priming. : ; "The foregoing advantages are based on the boiler being of good de- sign with straight, submerged, solid-drawn, steel tubes and with drums made throughout of wrought steel. In such a boiler we will have char- acteristics that will rank higher than those in our good, old friend, the cylindrical or Scotch, and that will make it capable of employment in vessels of all classes." : Mr. George W. Dickie, manager of the Union Iron Works, San Francisco, endorsed the declaration in favor of straight tubes. He pointed out that the difficulty of replacing bent tubes was serious. But while the subject was unquestionably one of the greatest importance in ship development, Mr. Dickie did not think that the water tube boiler had yet reached the stage where it was to entirely displace the cylindrical. Naval Constructor J. J. Woodward, who is stationed at the Newport News ship yard, pointed out that the introduction of the water tube boiler involved questions of space and weight in ship construetion, and that even the matter of stability might be embraced by reason of the fact that when the tanks are filled a large weight is added to the bottom of the vessel. Summarizing he said that the water supply for the boilers, when large plants are carried is a matter of importance to the naval architect. Mr. John Platt of Thorpe, Platt & Co., of New York, took a position similar to that of Mr. Dickie in the declaration that the water tube boiler which fills all requirements has not yet been devised. Practically, all the water tube boilers in the British navy, he said, had given trouble. © le Mr. F. L. DuBosque:favored water tube boilers for ferry boats. He stated that his company had found it impracticable to 'use cylindrical boilers when the ferry boats run 75 per cent of the time and remain: in the slip 25 per cent of the time. Water tube boilers had been in use in some of the ferry boats in the harbor during the past three years and the theory outlined had been carried 'out nicely. 'Moreover, actual experience 'had proven that the use of boilers of this type enabled a saving of from 15 to 18 per cent in fuel in the service of his company. j Mr. W. D. Forbes spoke of the lack of provision for cleaning water tube boilers as exemplified by the experiences of the men who had in charge the making of repairs on the boilers on the United States vessels engaged in the Spanish-American war, and Mr. McFarland closed the discussion with a few brief remarks. LIFE SAVING APPLIANCES. SUGGESTIONS AS TO DEVIOES FOR LAUNOHING SHIPS' BOATS--AN INTERESTING PAPER ON A VERY IMPORTANT SUBJEOT. Mr. John Hyslop, official measurer of the New York Yacht Club, and who was on board the steamer Mohegan when she was lost on the Manacles about a year ago, was present in person and read his paper "Suggestions as to Improved Appliances For Launching Ships' Boats." It was illustrated with a working model. Mr. Hyslop directed attention first to the fact that the vast develop- ment of ocean travel in the past half century and the increased water traffic of every kind has been unattended, excepting in rare instances, with any change whatever in the method of launching ships' boats, and with only here and there such changes in detail as leave the vital requisites yet to be found, recognized and put into use. It is impossible to believe, he said, that the difficulty lies wholly in the lack, with proper inducements, of ability in contrivance. He had stood four different times on ships' decks when it has been necessary to launch boats to save life, and on none of them was this quickly and effectively carried out. In the search for new forms of davits it is questionable if the same identical form will be found equally applicable in all cases; and even if the same form is found to be generally applicable, some modification of detail