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= IN PERCENT. CT STL SAVING TUDE TULLE LEAPED Fig. 5. Curve showing saving in per cent of shaft horsepower effected by Sim- plexrudder. Tak- en from Model basin test STATURE LCO ULL . SPEEO IN KNOTS. ously being better than the bare sin- gle plate rudder. It will be noted that there is a saving in shaft horse- power of 12 per cent. it is found that compared with the single plate rudder, the Simplex rud- der will increase the speed from one- half to one knot for a given fuel consumption, or conversely, for the same speed, a saving in fuel of from 12 40 17 per cent is obtained. Another advantage of the Simplex rudder, is the fact that it reduces vibration because of its rigid con- struction. Also because of its per- fect streamline section, the propeller jet is received without shock and the water flows smoothly past the rud- der resulting in an even propeller torque which is conducive to smooth running qualities. There is usually a noticeable reduction in vibration when backing as the flow of the pro- peller is very much improved and the propeller turning up evenly, the ves- sel becomes remarkably steady. In the beginning of this article reference was made to the practical construction of the Simplex rudder and attention is now directed to Fig. 6, showing the Simplex rudder fit- 26 In general, ted to a 9600-ton deadweight twin- screw naval tanker. As previously stated and as will be noted from the photograph, the rudder is built of plate and is welded throughout. The interior is amply subdivided by con- tinuous vertical members and the re- quired number of horizontal inter- costal stiffeners. The structure is then solidly reinforced by a heavy dou- bling plate wrapped around the rud- der body as shown. By building up the rudder in this way and omitting the usual cast or forged frames the weight is greatly reduced and as a matter of fact, such a rudder is cheaper to build than the conventional single plate rudder with its thick center plate, forged stock, heavy rudder arms and many pin- tles. The entire rudder including the cylindrical post and bearings can be made and assembled in the shop and installed as a complete unit in very little time. Furthermore, the rudder, being of convex shape and like a cellular tank, it is practically indestructible | and its buoyancy is such that little or no weight has to be taken on the carrier or bearings. As a matter of TDUUVTUUONYATUVLTUTUDEEY EEUU EEEUU EATEN: Fig. 6. Simplex rudder fitted to an 8000-ton deadweight twin screw naval tanker. The rud- der is built of plate and welded. The interior is subdivided by continuous ver- tical members and _ horizontal intercostal stiff- eners. Heavy doubling plate wrapped around rudder body UDNYTIOVUNQUTEVEUYI OOOO TVUOUQ DOTA MARINE REvIiEw—December, 1931 fact, there is so little stress put on the bearings that the lignum vitae bushings do not have to be renewed in from 5 to 7 years. It might be added in closing that the Simplex rudder, being of the bal- anced type, is admirably suited for vessels of the Great Lakes where the balanced rudder has been in use for many years and where its ad- vantages are so well recognized. Com- pared with the single plate and box type of balanced rudder in use there today, the Simplex rudder will not only effect an appreciable increase in speed and reduction in power but should also prove particularly advan- tageous because of its remarkable steering and maneuvering qualities, both when going ahead and when go- ing astern. Moreover, for Great Lakes service, since it is not radically different from the rudder arrangements in use there at present, the Simplex rudder, offers a very real advantage in that pro- peller changes and stern bearing re- pairs can still be made without dry- docking the vessel, that is, by trim- ming the ship. Perhaps one of the best known Simplex rudder installations is that on the new quadruple screw S. S. MonARCH OF BerRMuUDA of Furness Withy Co., a vessel of 23,000 gross tons which has just completed suc- cessfully, a series of trials prior to entering service between New York and Bermuda. Other important com- panies who have adopted the Simplex rudder are the Hamburg American line, who have 22 installations, Standard Shipping Co., 16 ships equipped and the Russian govern- ment with 23 installations. Wireless on Georgic Marconi equipment on the new White Star line mo‘or ship Gxorerc, which was launched at. Belfast Nov. 17, will include both long and short wave transmitters, thus afford- ing the ship direct wireless telegraph communication with shore at any time during her voyages, wherever they may take her. The long wave trans- mitter will be effective up to about 1500 miles from land, and the short wave lengths from that distance up to a world wide range. The facilities will also extend to other ships, with which the Grorerc will be able to communicate direct. Suitable receivers are fitted with these transmitters, their design being in- fluenced by modern marine conditions. Very selective turning circuits will be introduced to eliminate unwanted signals. The Inland Waterways Corp., which operates the Mississippi barge line, cleared approximately $150,000 during the first seven months of the current year. It has put 321 steamboats and barges on the Mississippi and its tribu- taries. |