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24 MARINE REVIEW. [April 25, CONSTRUCTION OF TORPEDO BOATS AND DESTROYERS. BY GEORGE HERBERT WILSON. RUDDER CARRIERS AND DEOK BEARINGS. In dealing with the above fittings a thorough investigation into the requirements is necessary to the proper designing of the same. I have outlined the construction followed in three cases on boats built and build- ing. The first of these, type C, plate 13, shows the rudder carrier used in connection with the rudder type A, plate 8, which is the overhung type of rudder. To gain a proper support and absolute rigidity, as is necessary to the working of these parts, a very strong connection to the hull is needed. With this end in view the horizontal and ver- tical plans were made very stiff and a sufficient number of rivets of the proper size was provided. Ample strength was thus given to resist the strains due to the weight of the rudder and those oc- casioned by racking. The stationary part of this group was made of cast steel, shaped to conform to the hull with a recess on its top face to receive the bearing ring and carrier. A com- position bushing gave a good bearing surface for the rudder stock. The rudder carrier was made up of a forging of steel, finished on all of the working faces, bored to suit the stock and a square hole cut through it to re- ceive a tapered key. An intermediate bearing ring was also fitted between the = bearer and the carrier of composition, thus providing good working surfaces —this ring being readily renewed. As all the parts of this arrangement are located at the upper deck of the boat in question, they are accessible for fre- quent oiling and cleaning. The second of these sketches shows a bearing and carrier as used in con- nection with the rudder shown in plate 9, type B, and is represented by type A, plate 12. This construction, it will readily be seen, applies to the protected rudder, one which is hung underneath the keel of the boat. The questions of supporting the weight of the rudder and resisting the various strains are still to be considered, but the conditions of the hull structure are radically different. Excepting for the shape of the bearing and the shape and material of the carrier, the con- struction is similar to that described above. The bearer in this instance 62°29 oo 0 yy! fx Dy is spread out: so as to cover considerable deck surface, thereby distribut- ing the load in that vicinity. To allow for the sheer of the deck the palm of the bearing is tapered. A recess for the carrier, as in the other case, was made and a bushing of brass for the rudder stock was provided. Pa.) AL In the rudder carrier the departure from the previous method is some- what greater, in that the material and shape have been changed. As re- gards the former the general knowledge of the two metals in question should decide the matter, but, when properly designed and when assur- ance is had of a good casting, the composition has a number of features in its favor. It is needless to say, however, that, considering the depend- ence to be placed on the parts in question, too much care cannot be given to their design, and from my own experience I would suggest the wrought steel as the better practice. Regarding the latter consideration, the change in shape, I have but one suggestion to make; and that is:that the fillet between the vertical and horizontal parts should be of'a larger radius, making a stiffer bearing surface all around. : : Coming now to the last style of bearer and carrier: Type B, plate 12, shows the construction employed in connection with the rudder shown in this article on plate 11, which is also a rudder of the protected type. In SI SS Sh XQ) N \\\s this arrangement the bearer is somewhat similar to that just described, but the carrier is entirely different. In the bearer the same idea, that of spreading the weight over the deck plating, is carried out, but the length of the bearing surface on the rudder stock is longer and it has the addi- tional advantage of being a white metal bearing, thereby increasing its efficiency. On the upper face the bearer is recessed to receive the; bearer ring. Instead of making the bearer casting with a bevel to fit the deck it is made straight and a bevel liner of brass is fitted between it and the deck. This method is far more satisfactory, as a more nearly perfect fit is