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To Install Contra Rudders On Twenty Vessels After careful investigation, in- cluding model experiments and a check-up on the results obtained in actual service to establish increased efficiency, the American Hawaiian Steamship Co. has decided to install contra rudders on 20 vessels of the line. at an expenditure of alm‘ost $250,000, which amount largely rep- resents. labor costs. This work is now under way and it is expected that all of the installations will be com- pleted by September, Experience with the contra pro- peller and contra rudder, the latter being a combination of the contra propeller and streamline rudder, is not something new with the Amer- ican Hawaiian Steamship Co. For the past six years, by experiments at the United States model basin and then by checking the results in actual service over an_ extended period under all year around condi- tions, the company has definitely es- tablished to its own satisfaction the economies that are possible by the use of this device. Model Experiments Conducted The first step in the company’s program of investigation was a series of model basin tests in the Wash- ington tank with a 20-foot model of the S. S. Daxkoran class of ships. The results of these tests at 10,500 tons displacement indicated a saving of 220 shaft horsepower or 17.7 per cent at 10 knots and a saving of 290 shaft horsepower or 13 per cent at 12 knots, with savings at inter- mediate speeds lying between these two sets of figures. On the basis of the model perfor- mance a contra propeller was in- stalled on the S. S. PENNSYLVANIAN. The performance of this vessel in actual service was then carefully ob- served. Averages of the _ perfor- mance of the PENNSYLVANIAN for three years prior to the installation and for four years after the installa- tion, were found to be as follows: Before installation, speed, 11.63 knots, displacement 9045 tons, fuel consumption, 210 barrels per day. After installation, speed, 11.81 knots; displacement, 9642 tons; fuel con- sumption, 187 barrels per day. Ad- justing the fuel consumption before installation to the average speed and displacement after the installation, the fuel consumption before installa- tion becomes 229 barrels per day, or a difference of 42 barrels when com- pared with the fuel consumption af- ter installation, which represents a gain in fuel economy, due to the contra propeller, of 18 per cent. The improvement over the results indi- cated by model basin experiments is attributed to better steering and re- 26 duced yawing in actual sea service. About a year after the installation on the PENNSYLVANIAN, the American Hawaiian Steamship Co. took over the Williams line including the S. S. WILLHILO, renamed the ARIZONIAN which had been fitted with contra propeller shortly before. The av- erage performance of the ARIZONIAN for seven voyages prior to the in- stallation and for three years after the installation is given in the fol- lowing results: ~ Before installation, speed, 10.44 knots; displacement, 12,425 tons; and fuel consumption, 200 barrels per day. After installa- tion, speed, 11.62 knots; displace- ment, 10,225 tons; fuel consump- tion, 200 barrels per day. The fuel consumption before installation, ad- justed to the conditions after instal- lation, was 242 barrels per day showing a fuel economy due to the contra propeller of 17 per cent. The third vessel to be fitted with « contra rudder, the S. S. GOLDEN Sun, one of the transpacific fleet, from average performance for 18 months before installation and two years after installation, showed a gain in fuel economy of 15 per cent. A complete article on the contra rudder fully illustrated giving de- tails of construction and data on performance was published in the February, 1932 MARINE REVIEW. The saving due to the use of this and similar devices may be realized in reduced fuel consumption for the same speed or increased speed for the original fuel consumption. Orders received by the General Electric Co. during the first quar- ter of 1934 amounted to $38,148,- 654 compared with $25,511,644 for the corresponding period of 1933, an increase of 50 per cent. Correction Is Made In the item, page 45, April issue, re- ferring to two pipe line dredges or- dered by the United States engineer office, Kansas City, Mo., from the Mari- etta Mfg. Co., Point Pleasant, W. Va., it was erroneously stated that these dredges were to be similar to the JAD- WIN and Burcrss. They are to be similar to the dredges Carr. MERI- WETHER LEWIS and CAPT. WILLIAM CLARK, built by the same company for the same United States engineer of- fice. The general dimensions of the dredge Capt. MERIWETHER LEWIS are: Length overall, 268 feet, 114% inches; length between perpendiculars 260 feet; breadth overall, 84 feet, 83% inches; breadth molded, 50 feet; depth molded, 8 feet, 6 inches; and draft, 4 feet. The Capr. MERIWETHER LEWIS has side paddlewheels driven by two tan- dem compound reciprocating steam engines developing 1500 horsepower. MARINE REVIEW—June, 1934 Use of Diesel Engines by The United States Navy In recent Washington reports to Steel, the navy’s increasing use of and interest in the diesel engine is noted as follows: Diesel engine manufacturers are in the sun and will continue to be for sometime to come. The navy, in gen- eral, is being dieselized. All navy small boats now are being powered with diesels. Large naval vessels are being equipped with diesel generator stand-by units for supplying electric current. One basic adaptation of diesel en- gines is that of prime movers for all emergency generators in surface craft. Some 28 vessels recently placed under contract will be so equipped. Diesel engines are also being considered for driving generators for auxiliary power and lighting. A number of harbor tugs recently have been dieselized. One of the most interesting diesel engines so far delivered to the navy is a 12-cylinder, V-type, 950-horse- power, 729 revolutions per minute, 8 x 10 inches, 2-cycle Winton engine. This engine is now undergoing tests at the engineering experiment station at Annapolis, Md. It is of welded, rolled steel plate construction and has an underslung crank shaft. This is the prototype of sixteen 16-cylinder diesel engines which the navy has ordered from Winton for powering four sub- marines now under construction. In these tests, the navy is paying special attention to bearings. It is using precision bearings and needle bearings largely. The precision bear- ings are made by using a very thin layer of bearing metal with a heavy steel back. Antifriction bearings are being studied with a view of greater application in diesels. Tests are be- ing made with roller bearings for the main and wrist pin bearings. Cooling diesel engines by fresh wa- ter whenever practicable has been adopted by the navy. All investiga- tions so far indicate that no additional weight is involved by such policy and the problems of maintenance and op- eration are greatly reduced. Weight of diesels is being brought down in every way possible. Where castings are used, they are of the nick- el, chrome or molybdenum series, to permit thin sections. Aluminum pis- tons are used throughout. All excess weight is carefully removed from the crankshafts and other moving parts. The Marine Equipment Manufac- turers association has submitted a proposed basic code of fair competi- tion. A public hearing on this code, be- fore Joseph Dilworth, deputy adminis- trator, was to be held in Washington beginning on May 22 and continued until completed.