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transactions of the society available in June, 1932. Titles and names of the authors of these papers and brief abstracts follow: 1. Determination of Stresses in Plat- ing from Strain Measurements, by Prof. William Hovgaard, member. The author of this paper is well known, not only in the United States but abroad, for his valuable contri- butions to the scientific exposition of many problems in naval architecture. In the present paper he has developed a method of determining stresses in plating by measuring the strain. He defines stress as a force per unit area whether direct (normal) or shearing (tangential) while strain is defined as the unit elongation, contraction or distortion produced by stress. Bend- ing moments produced on a ship by external forces, such as buoyancy and gravity are distinguished from stress couples produced on any given trans- verse section by the moments of the stress forces about the neutral axis. Under static condition the bending moment and the stress couple acting on any given section must be equal. The author points out that in a few cases in which strain measure- ments have been made on the plat- ing of ships, only longitudinal strains were measured and the corresponding stresses were obtained by multiply- ing the strains and the modulus of elasticity. It is suggested that it is not safe to neglect the transverse stresses except where experimental evidence shows it to be justified. Based on this reasoning more com- plete strain measurements than hith- erto as in the case of the WorrF tests were made on the United States de- stroyers PRESTON and Bruce at the Nor- folk navy yard under the direction of Commander C. O. Kell of the construc- tion corps of the navy. A complete set of measurements were made on the PRESTON by the naval construction stu- dents of the graduating class of the Massachusetts Institute of Technology and formed together with an analysis of the results the subject of their thesis. The tests on the whole were similar to those on the Wotr, but the strain measurements cover not only the upper part of the structure a8. in. the WoLr, .but. also the lower, their readings being taken on the inside of the plating. Strains were measured not only longitudinally, but also transversally and in diagonal direction. The analysis shows that in Many cases the transverse strains were appreciable and had an influ- ence on the longitudinal stresses of the order up to 10 or 15 per cent. The analysis of the Preston tests shows that with reasonable assumption as to the effectiveness of the various structural members, the modulus of elasticity, determined by a comparison between calculated and measured de- flection and bending couples, corre- spond very closely with that of the ma- terial, about E equals 13,000 tons per 14 square inch. The method is described and a mathematical analysis is presented. 2. Investigation of Structural Char- acteristics of Destroyers, Preston and Bruce, by Lieut. Commander Claude O. Kell (CC) U.S.N., visitor. This is a most interesting investi- gation based on full size experiments of the structural characteristics of de- stroyers. Particularly is the investi- gation of value in the possibility of re- ducing excessive weight by a different distribution of weight in the design. Two of the destroyers recently selected for scrapping the Preston and the Bruce were selected by the bureau of construction and repair of the United States navy for use for structural re- search purposes. The PRESTON was Se- lected for sagging tests, because of the excellent condition of her shell plating near the ends of the ship where the shearing forces would be greater. The BRucE was used in the hogging experi- ments. The paper relates in detail the necessary work of installation of sup- ports to rig the destroyer Preston for the sagging tests. Cradle plates were fitted neatly to the girth of the ship and under the keel at frames 7 and 170, a distance of 285 feet 3 inches apart. With the ship entirely supported at the ends, in certain sections the bend- ing moments were much greater than those for which the sections were de- signed to withstand. This condition existed at the quarter lengths of the ship and was particularly critical in way of the knuckle at frame 154. While the PRESTON was subjected to maximum bending moments amidships of approximately 31,272-foot tons, the deck stringer plates buckled generally between frames 131 and 143. The buckling was particularly pronounced aft of the transverse bulkhead of frame 137. The cause of this weakness was probably the ending at bulkhead 131 of the intermediate and outboard deck girders. So that the results of the hogging tests might be comparable to those of the sagging tests, it was necessary to so support the Bruce that the bottom plating would not be subjected to forces other than those that exist with the ship afloat. From the results of the sagging tests, it was expected that the hull would fail in hog by buckling of the bottom strength members and shell plating. The BrucEe was supported by her side shell plating. In conclusion the author gives the following facts: 1. Both ships failed in compression through instability of longitudinal members. In these tests the dynamic forces and reversal of stresses experi- enced in service were not represented. These may or may not have revealed other weaknesses at lower stresses than those at which the longitudinal strength members collapsed. 2. These experiments demonstrated the importance of continuity of struc- ture. MARINE REVIEw—December, 1931 It is interesting to note from this paper that the studies of the failures of these destroyers point to ways of an improvement in formerly accepted de- tails of design and that these have been incorporated in recent work. There are many photographs and the paper is presented in a clear and in- teresting manner. 3. Recent Developments in Special Quality Steels for Shipbuilding, by Wil- liam Bennett, member. The purpose of this paper is to di- rect attention to recent develop- ments in steel manufacture which are receiving the serious considera- tion of shipbuilders and engineers everywhere. The use of wrought iron for ship eonstruction began early in the last century, and the reason for its adop- tion, in preference to wood, was as much for economic reasons as for any other. The first vessel of iron was stated to have been the VULCAN, built near Glasgow, Scotland in 1819. The first iron passenger vessel to be placed on the transatlantic route ap- pears to have been the Crry oF GLAs- cow in 1850. In 1856 the Cunard com- pany placed in service its first iron paddle wheel steamer, the Persia of 350 feet in length. The use of iron for shipbuilding was well established, when, in 1873 Sir William Siemens developed the open-hearth process for making ordi- nary low carbon steels. The advan- tages of mild steel in strength and weight were immediately apparent to shipowners and the new era com- menced. The tensile strength of steel, being about 25 per cent greater than iron, the thickness of the materials was reduced about 10 per cent. The author then gives average analysis for low carbon steel. He dis- cusses alloy steels in general, high elastic limit mild steel; admiralty D quality; stainless chrome-nickel steel; structural silicon steel; high tensile nickel steel; structural nickel steel and chromium manganese silicon steel, in each case giving a typical analysis. He also discusses the use of high tensile castings and corrosion resist- ing steel. Finally some typical cases are cited where special quality steel has been used in several notable vessels recent- ly constructed. Among these vessels are, the Cosulich liner, VULCANTIA, built in 1928 in which high elastic limit steel was used over about 60 per cent of the vessel’s length in the A, B, and C decks and top side shell in way of same. This represented a saving in weight of about 400 tons with corre- sponding beneficial effects on stabil- ity and deadweight. In the North German Lloyd liner BREMEN, built in 1928, special high tensile steel was used in parts of the top and bottom structure. The report- ed saving was about 800 tons. Some 7000 tons of this steel is said to have been used in this vessel. The material