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See tionally high-speed craft TURBINE VS. RECIPROCATING ENGINE RESULTS. Only four battleships, three ar- moured . cruisers, and two _ torpedo boats were passed through their steam trials during the year by the British admiralty whereas in the previous year there were thirty-four vessels--nearly four times the number--and these in- cluded one battleship, eight armoured cruisers, a protected cruiser, eight scouts, and sixteen destroyers. This comparison might suggest a relaxation in our effort to maintain our naval su- premacy; but last year was exceptional in one respect, this year in another. Last year there were Devonshire cruisers which had been delayed owing to a commendable in- crease in the gunpower when the ves- sels were far advanced towards com- pletion, and the great number of de- stroyers fell: within last year owing to delay consequent upon a change of Opinion as to the type of craft, the heavy river class having been pre- ferred to the 30-knot boats, which be- came disaster. "suspect" owing to the Cobra This year we have only two torpedo craft, because development in opinion, after due consideration and experiment, favors .light and excep- with express boilers using oil fuel and driven by 'turbine machinery. These changes in- volved delay; but now boats are fol- lowing each other in rapid succession. The two boats tried this year are of the 26-knot type, now to be called first class torpedo boats instead. of coastal destroyers. They are a distinct suc- cess, easily realizing their (26 knots speed for less than 4,000 horsepower, and the lower consumption | of fuel, "quite 40 per cent less than with the earlier craft, gives them, for the same weight of fuel, a much greater radius of action. In a few months we shall have the trials of the first of the new 33-knot boats, which are of 800 tons, and have turbine machinery. of 15,000 I. H..P.--an enormous power for such light craft. _ Of the battleships tried three were of the King Edward VII. class, and the fourth was the much-discussed Dreadnought. The results of the trials of the former may first be dealt with, as they throw light upon the signifi- -cance of the performance of the lat- ter, and it may be well to tabulate the data for all eight ships of the King Edward class, as basis for deduction regarding the later ship and the name of the constructor of the machinery-- the Commonwealth, Dominion and Hindustan were also built by the en- gine contractors; the other ships were of Dockyard origin. It will be noted the Africa, was engined by ' King Edward VII. (Harland & Wolff)-- 5 included = six THE MARINE REVIEW that on the low-power trial Fairfield got the lowest consumption; on the three-fourths: trial Messrs. Humph- reys, Tennant & Co., are lowest with the Britannia, and Vickers have the lowest result for full power. The three last ships on the table were those tried this year, and one of these, Messrs. John Brown & Co. Ltd., Clydebank. RESULTS OF STEAM TRIALS OF EIGHT BAT- TLESHIPS OF KING EDWARD VII. CLASS. 1-5th 4th "Full Power. Power. Power. Coal consumption... 2.63fb _1.961b -171b Water consumption. 20ib $16.3 tb « 17:7 Ib Te ot ete a 3,760 12,844 18,138 Commonwealth (ro iele Co. ee Coal consumption... 1.73fb 1.67 tb 1.83 tb Water consumption. Re Oe Ab 1 Oe eID THe Re igor. 3:663° °° 125797 318,562 Dominion (Vickers)-- Coal consumption... 1.93tb --_ 1.68fb 1.77 tb Water consumption.21.6 tb 18.4 tb 18.3 tb Gee Rae cst es 3,889 12,843 18,438 Hindustan. (Brown, Clydebank) -- ; Coal consumption... 1.941b 7540 18 ID Water consumption. 202% tp 1715 fb) 610.3 1b PE ee ea rede 4 oc 3,718 12,929 18,521 New Zealand (Humphrys)-- Coal consumption... f= 1:881p. 2411p Water consumption. en geete Be lesies setae PI Ee ees 979 12,981 18,440 Africa (Brown, Giathalis Coal consumption... 2.001b 1.79tb . 1.87tb Water consumption. ce sagan pe aie Betas EER Pierce 3,682 12,860 18,698 Britannia (Humphrys)-- Coal consumption... 2.05tb 1.50tb 1.83 tb Water consumption. 21. 1b: 16.211b 18.55.ib MS Paes tere cat ee 3,539 13,087 18,725 Hibernia (Harland & Wolff) -- Coal consumption... 2.07Ib 1.59ib 1.92tb Water consumption. 19.9 tb 17.41ib 19.66\b, eee ics cick s 3,710 12,700 18,112 The machinery of this vessel was fitted with a system of forced lubri- cation, which gave most satisfactory results, and the Dreadnought. has since had the same method of lubri- cating the bearings applied. In. this respect, as in others, the turbine ma- chinery offers great advantages. In- stead of analyzing the results given in the table in detail, it may be prefer- able to note the averages. On the one-fifth trials of the eight ships the mean consumption of fuel was 2.04 lb. of coal per indicated horsepower per hour, and in the Dreadnought the cor- responding figure was 2.56 lb.' The working of steam turbines at a pro- portion of their full power is expensive; the best results are got by excessive er over-load:> It is true that the Dreadnought, like all warships, has special turbines of small power fon cruising, but even these cannot be al- ways worked at full power when the speed of the ship varies. It must be borne in mind, too, that the power of the Dreadnought was reckoned at the shaft instead of in the cylinders as in the other vessels, and about half the difference is thus accounted for. Only in five of the vessels was the water consumption taken. At one-fifth power the results showed a steam consump- tion: Of 20:5 1b per, 1. H..P. per hour. This includes the consumption of the auxiliary machinery, the power of which is not considered in arriving at the result. A point of special interest is that on the Britannia a trial at one- fifth power was made with steam sup- erheated to the extent of about 100 degrees F. On this test the coal con- sumption was 1.77 lb. instead of 2.05 lb. in the table, and the steam _con- sumption was 1819 lbs. instead of. 21 lb. This justifies the application of superheaters in some of the new tur- bine-equipped battleships. On the three-fourths trial the average coal consumption of the eight ships in the table was 1.72 lb. per indicated horse- power per hour, while in the case of the Dreadnought the result was. about the same, 1.7 lb.; but if allowance is made for the difference due to the method of taking of power the econ- omy in favor of the turbine ships is quite 10 per cent. On the full-power trial the economy of the turbine is still more marked. The coal consumption here was in the Dreadnought 1.51 Ib.; the mean in the eight King Edwards was 1.01 tb., and no. account is taken in the latter of power lost in friction. Practically the whole of this economy is due to the turbines, the boiler evap- oration being on an average about 10 lb. of water per pound of fuel. The steam consumption of the machinery in the Dreadnought at three-fourths power was 17.01 lb.--about the same as in the King Edwards--and_ on the full- power trial 15.56 lb., as compared with from 17.7 lb. to 19.66 lb. in the recip- rocating engines on the King Edward battleships, The. three cruisers tried this year were the Cochrane, built at Fairfield; the Natal, constructed by Vickers; and the Achilles, built at Elswick. . These belong to the Duke of Edinburgh class, of 13,550 tons displacement; the - Prototype and the Black Prince were tried last year. The sixth vessel, the Warrior, also Dockyard built and en- gined by the Wallsend Slipway & En- gineering Co., will go on trials in January.. The five vessels already tried had an average coal consumption. at one-fifth power of about.2 lb., the Els- wick ship coming out lowest, and the Duke of Edinburgh, engined by. the same firm (Hawthorn, Leslie & Co., Ltd.), highest; at three-fourths power the average was 1.92 lb., and at full power 2.06 lb., so that it will be recog- nized from a comparison of these re- sults with those for the Dreadnought that with an arrangement of cruising turbine more suited to the variable speed of ships, or a determination to limit the range in speed in peace to a specific rate for cruisers, the turbine