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strongs, Hawthorns, Lairds, Thorny- c-oft and White. The dimensions given in the tenders were as follows: Length. Displacement. PEPOMES ves et 238% ft. 600 tons. ors Bo acs BOO atte 500 tons. iL athcals\ > 2 is Os coer 260°) Tt 650 tons. Thornycroft ...-....-+. 25° tty 650 tons. PVte vere e see ee 250 4 tty 540 tons. Orders were finally placed with each firm for one vessel. The dimensions of the actual vessels were: Length. Displacement. PANemstrones ..... 62.5 250 ft. 860 tons. Meeruois .... sss. 5. . 205 ft 865 tons. Pads oc ee ee 270% 890 tons. PRORNVCEOLL 61. eee eee 270 ft 895 tons. DES ce es cee ee 270 ft 890 tons. By that it would be seen that con- siderable modifications were introduced by the builders acting in conjunction with the board of admiralty. All the designs were most carefully worked 'out in every detail and brought into line, most of the parts being inter- changeable, and the main engines, for instance, were' practically the same in each boat. All the vessels had now 'been run over the measured mile. The trials were not yet complete, but as a class they 'had got their speed, and the results had quite justified the original anticipations of the government. An- other point to which he wished to re- fer had to do with Mr. Thoznycrofit's statement concerning the speed of the Tartar. He. said, "The Tartar, the fast- est of the class, has maintained a speed of 35.36 knots on a continuous run of six hours, or practically 10 knots more than the river class could maintain on a four instead of a six hours' trial." He did not concur with that state- ment. If Mr. Thornycroft had stated that-the Tartar was six knots faster than the river class when similarly laden, he would not have been far wrong. Sir Philip went on to say that it had been known for many years that. while over a great range of speeds for a given vessel shallow wa- ter involves an increase of resistance and a falling off in speed, yet, on reaching a sufficiently high speed the resistance becomes less than that in deep water, and the speed attained is, in a corresponding degree, increased. If facilities for running high-speed ves- sels of this type in deep water existed at several points round our coast it would be very easy to prescribe that all trials should be made in circumi- Stances in which the recorded speeds might be accepted without correction; but the only course of the kind at Present was at Skelmorlie. In the "tiver" class the effects of the Maplin course was to diminish the speed, and if the speeds recorded had been taken Without correction, some of the class would have failed to attain the speci- fied speed. It was necessary either to Make an allowance for the effect of 'TAE Marine REVIEW depth, or to run the vessels in deeper water, and no injustice was done to the river class in this case. Our :pres- ent need was fuller information on this matter, in view of its increasing im- portance. The institution had already in its records Captain Rasmussen's pa- per on the Danish torpedo boats ex- periments, the valuable account of Colonel Rota's model experiments at Spezzia, and the papers contributed by members of Messrs. Yarrow's firm; and he was able, by the kindness of Messrs. Denny, to contribute for rec- ord in the "Transactions" the data ob- tained from some valuable experiments made by them only a few months ago with models of vessels of the form and displacement under consideration. Sir Philip concluded by saying that steps would be taken 'by the admiralty to obtain a series of experiments with the 33-knot vessels in order to get more adequate data. Admiral Sir Cyprian Bridge said that the torpedo boat destroyer was the only man-o'-war of any class, from the biggest to the smallest, which was evolved from deliberate strategical and practical experiments carried on for some considerable time beforehand. Referring to the fact that the Tartar, intended to be a 33-knot boat, had un- der certain conditions developed 35.36 knots, Sir Cyprian said that it was es- sential that officers in command of such boats should know exactly what speed their vessels were capable of attaining. If a fair and equitable sys- tem of trial trips could be devised it would be greatly in favor of the effi- ciency of the class. The Hon. Chas. Parsons, dealing with the relative merits of turbimes and reciprocating engines, said he thought 'Mr. Thornycroft did not state the case fully enough. He did not give the radius of action of the "coast- al destroyers," or of smaller boats equipped with reciprocating engines. In the absence of this information it was very difficult to argue the case. Mr. Thornycroft stated also that since the change to turbines took place the cost per horsepower had gone up con- siderably, but when they came to very large powers--in the 33-knot destroy- ers --the price fell. Surely, however, some consideration must be given to the dates when the boats were built. It was questionable if the price could really be compared. In fast vessels on the whole the turbine was cheaper than the reciprocating engine. At least he had that opinion, and it would be interesting to hear what others had to say. a Sydney Barnaby, referring to 4 the - 17 question of freeboard, said the idea seemed to have been to keep the boats as low as possible in order to get in- visibility; but while it was a good thing for a torpedo boat, it was not so in the case of a destroyer. In such a vessel they wanted'a good gun plat- form and a good all-round view, and increased seaworthiness was more im- portant than the question of invisi- ~ bility. He thought Messrs. Yarrow were the first to point out the ad- vantages of a 'deep fridder, The types that were seen were very. di- verse. When going astern at full speed the form of rudder usually adopted had one disadvantage--that the water boiled up at the stern, and there was thus an increased twisting movement and difficulty of control. If it were considered necessary to con- trol the rudder at the maximum speed there might be advantages in such a form as was adopted when the area of the rudder extended above the water line. Sir John Thornycroft differed from Sir Phillip Watts in his comparison of speeds. He thought the number of knots Sir Phil- lip -had cut off in the case of the Tartar was excessive, and he would put a figure nearer that given by his son. Admiral Sir G. Noel said speed was not the only necessity in a destroyer, and he hoped armament would also be considered. It was absolutely no use for a destroyer to be speedy enough to overtake the enemy if it were not then able to sink it. Arma- ment at present was absolutely inadequate, but he understood the Admiralty intended to increase it. : He further urged that as no British pos- session produced oil fuel, it was a ques- tion for mature consideration whether it was wise to equip war vessels for such fuel. Moreover, the protection afforded by coal in bunkers was dispensed with if oil fuel were employed. In reply to Sir Phillip Watts, Mr. Thornycroft said that as the Tartar had run her trials on the buoyed course of an admiralty measured mile which had . been approved for the trial of the particu- lar vessel, he thought he was justified in describing the speed as that officially re- corded, and as the depth of water--about 10 fathoms--at which the trial was run was a depth at which destroyers might be expected to perform a large part of their service, it was unreasonable to make any deduction in speed for any advantage which might be shown at this depth over a greater depth for this particular speed - and size of vessel; further, no corrections had ever before been made and very little was known about the subject.