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20 THE Marine. REVIEW January, 1910 ' Naval Architects and Marine Engineers (Continued from December Issue.) HE members assembled at 10:15 o'clock, Friday morning, with President-elect' Taylor in the chair. The first. paper. considered was "The Design of Sub- marines,' by Morley F. Hay, which, in the absence of Mr. Hay, was read in outline by D. H. Cox. This paper will be published later by THE REVIEW. Discussion on Mr. Hay's Paper. L. Y. Spear (Communicated): I re- gret that unavoidable absence from the meeting deprives me of the op- 'portunity to hear the discuss:on of Mr. Hay's very interesting paper. In reading over the paper, a few com- ments have occurred to me, which it would seem proper to have, brought out at the meeting. To that end the following short discussion has been prepared: In connection with the questlon or the strength to resist deep submerg- ence, it may be remarked that the navy department now requires the contractors to submerge all subma- tines to an axial depth of 200. ft., where they must remain for 10 min- utes without developing any injuri- ous permanent deformation. On. the > Atlantic. seaboard, a larze part...of the work of the boats is necessarily done in water of less than 200 ft., and in this fact may be found an adequate reason for the adoption of this standard. which is higher than that required by any European: goy- ernment. The tactics of the.subma- rine boat will probably never require an actual submergence of more than 65 ft., but by disarrangement of ma- chinery or errors on the part of the crew, greater depths may be attained involuntarily. While with the exer- cise of reasonable care and judgment, the chances of such involuntary deep submergence 'are very remote, never- -theless it should be provided for in view of the disastrous results which would follow the attainment of crush- ing depths. The adoption of this standard in this particular case re- moves at once all danger from this source over the greater part of the theater of the boats' operation. More- over, the vessel possessing such strength is free to take to the bot- tom for repair purposes or for the conservation of the battery charge under circumstances where her pres- ence on the surface is prohibited. For operation in very deep water, it is impossible to absolutely eliminate all -sent to that statement. possible danger from this source. The above standard, however, reduces it to negligible proportions, since the time required to reach a dangerous depth is so extended as to afford the crew ample opportunity to take advantage of the means provided for increasing buoyancy and to correct the original source of trouble. Stability Discussion. On page 5, in the stability discus- sion, the author referring to the s:n- gle hull vessels in contra-distinction to the ship form vessels, states, "while the GM, in figures, is less than with the other type." In that connection it might be well to point out that the statement evidently refers to the GM in the surface condition, as is clearly indicated in other parts of the paper, the GM submerged of the single' hull. type is, as a rule, greater than that of the other type. In other words, while on the surface the ship-forms as a rule have a high- er Gm; the process of trimming re- verses these conditions. On page 7 the author. states, "It must be evident that the tactics em- ployed in a naval war with vessels having such widely divergent qualifi- cations must be entirely dissimilar." I find myself unable to give full as- Taking things as they nowr stand, I fail to see how the possession of one or two knots additional surface speed can affect tactics so long as that surface speed is materially below that of capital ships and destroyers. It should al- ways be remembered that the sub- marfine boat, when driven on the surface with her heat engines, is in daylight devoid of any offensive or defensive properties, and daylight op- erations are obviously the special field of the submarine. To pass fromthe surface condition proper for maxi- mum speed to the submerged condi- tion requires from 3 to 6 minutes. Remembering this and taking into ac- count the speeds of battleships, cruis- ers and destroyers, their armament, the range of the guns and the pres- ent perfection of marksmanship, it is perfectly obvious that the submarine has 'no business on the surface any where in the neighborhood. of a hos- tile force. If she is to press her at- tack home, it is important that her presence should be undetected, and for this purpose as well as to avoid possible destruction, it is essential that she should pass to the fighting merged since, condition, i. e, the awash or _ sub- merged condition, outside the range of visibility. Essentials of Attack. J bis,. of © course; 19 -jush os true of -a beat having 4 «suri. speed of 15 or 16 knots as it is of gine having-.a speed. of 120 ore knots. Once submerged their tactics are of the same general nature, but if the higher surface speed has been attained at a sacrifice of the syb- speed and radius, then, as demonstrated, the can easily be chances of a successful attack are re- "duced in about the same proportion. "In other words, speaking generally, -the surface speed can. play no part 'whatsoever in battle tactics so long as it remains (as it must) materially less than the speed of capital ships and destroyers. General service con- ditoins, which need not be discussed here, call for a reasonable measure of surface speed combined with a radius of action suitable for the in- tended service. Any addition to such speed is necessarily made at a grave sacrifice of the really important quali- ties of the boat and can only result in a Serious decrease in-efficiency. It seems to me that the only exception to that rule is .a special case where there are a number of comparatively narrow channels to be defended and the number: of boats which can be assigned to such defense is limited. In this case, assuming the proper in- formation service, the' boats might be grouped at a centrally located base teady to take station at any threat- ened point. In narrow waters such as are here predicated, effective work might be done with a small sub- merged. speed and' radius, and might therefore be permissible to make some sacrifice in these quali- ties in order to increase the surface speed and thus shorten the time re- quired to reach the assigned station. Table of Comparative Qualities. Referring to the table of compara- tive qualities on page 9, the author's statement is strengthened by the con- sideration of the trial results of a single hull boat of later design than Type 9, where, on a_ displacement slightly in excess of 300 tons and a horsepower of 600, a surface speed of 13.3 knots has been achieved. These results place that type of single hull vessel midway between the two types of double hull mentioned. It might also be added that, with regard to cy