349 



Mar. Eng., Oct. 1912). (6) The largest oil tanker yet built, to carry 15,000 tons D. W., 

 Krupp (German) engines, 527 ft. long, 66 ft. beam (see also Engineering, April 19, 1912). 

 (7) To carry 7200 tons D.W. building by Frerichs & Co., Germany, for British owners 

 the Petroleum Steamship Co. The Junkers (German) engines are of peculiar construction, 

 two pistons in each Cylinder, the fuel being ignited between them (Junkers, German Soc. 

 N.-A., 1911, and Int. Mar. Eng., July 1912), (8) Cargo boat for Hansa line. Tecklenborg- 

 Carels Engines, largest; I. C. Engine yet afloat, viz. 1500 B.H.P., cylinders 19! inch diam., 

 35" stroke, 115 revs, on one shaft. (9) To carry 1500 tons. First American Diesel-engined 

 commercial vessel. M.A.N. (German) engines. Ship constructed by Staten Island 

 Shipbldg. Co., and engines by the New London Ship and Engine Co. of Groton, Conn. 

 (see Motor ship, June 6, 1912). 



Suction gas plants have been installed in two small experimental vessels, the " Elec- 

 tric Arc," in conjunction with electric drive (see Shipping World, January 3, 1912), and 

 " Holzapfel I," in conjunction with Fottinger transformers (see Holzapfel, I.N.A. 

 1912). In both cases after a period of trial the plant has been removed. An auxiliary 

 surveying vessel launched by Napier and Miller in 1912 is fitted with suction gas plant 

 and a six cylinder 225 B.H.P. gas engine. In Cas and Oil Power, October 3, 1912, an ac- 

 count is given of a 100 H.P. engine by Mr. A. M. Low which runs on solid coal direct; 

 and the case for alcohol fuel is stated in " The Motor," August 27, 1912. 



Many firms are perfecting the Diesel engine for marine purposes (see Engineer, 

 October 18, 1912, for German ), and others are using Gas turbines to obtain the advan- 

 tages of the low consumption of the I. C. engines without reverting to reciprocating 

 machinery (see Dugald Clerk and Hans Holzwarth, Brit. Assoc. 1912). 



Improvements. For a review of 50 years progress see Dr. Thearle, I.N.A. 1912. 

 Recent methods for ensuring sufficient strength with increased cargo capacity or speed 

 comprise (i) a development of longitudinal construction, (2) raising the middle por- 

 tions of the ship on arches, (3) forming fore and aft ridges in the side. 



Details of (i) were given by Mr. J. W. Isherwood, I.N.A. 1908. Clearer holds, 

 greater strength and a saving of about 10% of weight of structure, are obtained, as well 

 as decreased cost of building. The system has been adopted for three-fourths of the 

 tank vessels now building, as well as for many other types of vessels in Europe and 

 U.S.A. (see Cleveland, Marine Review, September 1912; also Standard, October 23, 1912). 

 The system had been adopted in 43 vessels of 176,000 tons by June 1910, rapidly in- 

 creasing to about 250 vessels of 1,200,000 tons by December 1912. (2) The " Arch " 

 system of construction was described by Mr. Maxwell Ballard at the Institute of 

 Naval Architects in 1911 (see also Shipping World, April 27, 1910). Three vessels of 

 1,500-2,000 tons each have been already built on this system, and two others were 

 under construction at the end of 1912. (3) The " Monitoria," built in 1909-10, was 

 the first vessel built with " corrugated sides " and gave the name to the system (see 

 papers by Mr. Haver, N. E. Coast Inst. 1910 and 1911, and Captain Macllwaine, 

 R. U.S. Inst. 1912). Four vessels of the type were afloat at the end of 1912, and three 

 others under construction, all of about 3,000 tons D.W. capacity. 



Anti-rolling tanks (see E. B. xxiv, 938; Watts, I.N.A. 1883-5; an d Frahm, I.N.A. 

 1911) are now being fitted in many large liners and war ships. Large chambers built on 

 opposite sides of the ship are about half filled with water, a transverse water channel 

 connecting the lower parts of the tanks, and air pipes the upper parts. Valves in the 

 air pipes regulate the movement so as to prevent synchronism with wave periods and 

 consequent rolling. Tanks were so fitted in the " Inflexible " and other warships of 

 very large metacentric height 30 years ago, and proved very useful, but the practice 

 has not been continued in later war vessels where smaller metacentric height is practic- 

 able (see also " Effect of Bilge Keels on Rolling," Messrs. Idle & Baker, I.N.A. 1912; 

 and"Applied Stability of Ships," Heck, Inst. Mar. Engrs. Oct. 1912). 



Increasing attention is being given to the study of Naval Architecture and Marine 

 Engineering in Germany and America as well as in England. Chiefly owing to the 

 advocacy of Sir W. H. White and the generosity of Mr. A. F. Yarrow, a national experi- 

 mental tank has in England been provided at Bushey. There is evidence of increased 

 power of adaptability of designers to produce vessels specially fitted for the trades on 



