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of the propelling mechanism; it is be- cause the screw has been alternately in and out of the water, acting in mid- air half the time, and the rudder like- wise, both transmitting pressure only when immersed, and neither being in a position to do its intended work when most urgently required. No steam engine or other power can pos- sibly obtain utility from or produce steerage way by the screw propeller when it is out of the water, hence safe, lucrative, and proficient naviga- tion is utterly impossible in associa- tion with racing. Besides the losses sustained in time. and maintenance during protracted passages, the insufficient or incon- stant immersion of the screw, and the consequent sudden and _ fluctuating strains thereby engendered, are re- sponsible for lost propellers, broken shafts, disabled machinery, inability of vessels to leave or enter port in bad weather, and in many other ways involving loss of life, vessels, and freight, waste of time and money in towage, .salvage, repairs and _ other- "wise, proving conclusively that in- congruity prevails and harmony is wanting between hull and_ propell- ing apparatus, and suggesting very forcibly that the requirements' of screw propulsion among waves are not fulfilled in. vessels' as" dé- signed at present, moreover, -that the propulsive effects of the screw are destroyed or lost owing to the natural propensity of vessels to lift their sterns clear of the water in a seaway. The behavior of the present vessels at sea indicates plainly that there is an excess of buoyancy on the after side of amidships, and a de- ficiency forward of that, hence their liability to bury their bows and raise their sterns, such being surely an im- perfection in the formation of the hull, capable of being rectified simply and inexpensively. It follows that racing and its attendant dangers need not be tolerated any longer as a matter of course, or as an imperfection which cannot be avoided. The screw propeller and rudder having been found to work most ef- ficiently at the stern in smooth water, 'it is merely requisite to: provide for their better immersion at that end in order to obtain their utility among waves. It is not necessary to mu- tilate the present design of the hull all fore and aft to admit of the screw being placed amidships, as has been proposed in telescopic tunnel arrange- ments, neither is it workable to double the draught by placing the screw amidships and con- structing an-appendage for its protec- advisable nor - "TAE MariNE. REVIEW tion under the present bottom, as has been recommended. All that need be done is to promote the principle of heaviness aft and lightness forward by substantially reducing the displacement or buoyancy of the immersed after- end--from the keel upwards to the top of the screw aperture--terminat- ing 'that portion of the vessel's run further forward than at present, and transferring the screw and rudder as far forward of their present position as would be consistent with their working efficiently. The displacement or deadweight support thus lost at the after end ¢ould be regained by in- creasing the vessel's amidship breadth and filling out the form from amid- ships to the stem, thereby creating a natural tendency to droop at _ the stern and tise at' the: 'bow at all draughts of water, also preventing the present upheaval of the stern among waves, and ensuring its continual im- mersion to such a degree as would render racing impossible. The transference of the screw, and rudder forward of the present situa- tion is of great advantage in securing their sufficient immersion to prevent racing and to obtain better propulsion. For instance, a 280-ft. steamer of ordi- nary design, pitching in a seaway, can lift her screw completely out of the water. Assuming that the screw were transferred 35 ft. forward, and the same upheaval taking place, it would be immersed about 4% ft. in the wa- ter, instead of being out of it, as at present. Such increased minimum im- mersion--important as it wndoubtedly is--does not represent the aggregate gain, asc ih the specihed: case, = Tire hull alterations requisite to effect the transference would be the means of further depressing the after end, con- 'sequently, in a seaway, the minimum immersion of screw and rudder would be at least 75 per-cent better than formerly. The upper portion of the stern, from the top of the screw aperture upwards, could be continued right aft, somewhat as at present, and to com- pensate for its greater immersion in a seaway, also to provide additional cargo space, it is recommended that its extreme height be made equal to, or even greater, than the height of the vessel's bow. It is marvellous to note how little has been done by way of improving the hull design for the prevention of racing. The outward form of sailing ships and steamers is so nearly alike that their main differ- ence lies in the means of propulsion. Considering the great disparity be- tween wind and screw propulsion, it must be admitted that one model is ommended. 17 most unlikely to suit the most efficient application of both. The steamer re- quires to be modified in a manner suitable for her means of propulsion. It has long been recognized that it is preferable for screw vessels to trim by the stern, both when light and la- den, and it is now hoped that the ad- visability of providing for the wants of the screw will be speedily acknowl- edged by the adoption of the special design and arrangement herein indi- cated. There is another benefit « of great importance that would accrue from-the adoption of the herein-men- tioned type of vessel. The heavy rolling in a side sea, now due to the great amount of water ballast in a steamer's bottom, would be very much reduced, as. part of that ballast would be unnecessary, the permanent struc- ture of the ship itself raising the cen- ter of gravity, and thereby reducing the rolling, making the ships more sea kindly, also improving the speed. The most useful method hitherto adopted for the prevention of racing has been deep-end and_ shallow-bot- tom water ballast tanks, and thereby the discrepancy has been remedied to some extent. However, the limit of improvement in that respect has been. reached, as deep water ballast tanks amidships have been tried and only proved a partial success, their use in light trim voyages inducing serious straining, and much expense' is in- curred in pumping the water in and out, also in keeping them clean for cargo; likewise with regard to deep side tanks, the latter occupying hold space which cannot be used for cargo. Governors have been used to limit the number of revolutions of the en- gines, and such have been highly rec- : However, it must be borne in mind that a thoroughly ef- ficient one can only lessen the risk of damage to the machinery. It cannot. possibly, even in the slightest degree, increase a vessel's speed or render the screw useful when it is not in the wa- ter, but fails to act at critical mo- ments when speed and steering power is most 'wanted. The screw propeller is certainly the most powerful and reliable, economi- cal and useful means of propulsion so' far introduced for sea-going purposes; likewise the modern marine steam engine is unsurpassed for supplying the requisite power economically and conveniently, any required degree of propelling power being thus available, and at the present time the full extent of its usefulness being only obtainable by fully-laden vessels in smooth wa- ter. It behooves all concerned to en-- hance the mercantile marine generally