NON-ROLLING PASSENGER LINERS. 107 



amounted to $30,000 or $40,000, a sum sufficient in a short period to equip the ves- 

 sel with a stabilizer. 



The equipments of more recent design are single gyros and much simplified. 

 These are illustrated in Fig. 11, Plate 45, showing a complete stabilizer plant for a 

 530-ton yacht assembled in the shop for test; also by Fig. 12, Plate 45, showing a 

 stabilizer for a light cruiser in its shipping frame. 



The ability to roll the ship has proved in actual experience to be important in 

 case of emergency to free the vessel from sand and mud banks, by opening the con- 

 tacting crevices and gradually liquefying the encumbent mass. This has been dis- 

 cussed in a former paper, also the field of the active gyro in rolling ice-breakers and 

 preventing them from freezing in when cutting through rivers and harbors during 

 the winter months. The most important use for rolling, however, is as an aid to 

 gunnery. 



As outlined, we have been accumulating a large amount of actual sea experi- 

 ence with various sized equipments. The Government has been of the greatest as- 

 sistance in encouraging the development. The war has seriously interfered with the 

 work, but even during this period the Navy has allowed us to complete the largest 

 gyro equipment yet attempted, and though the installation has been retarded by the 

 ship being in constant transport service, this fact has offered additional opportunity 

 for final testing. Fig. 13, Plate 46, gives a very good view of the U. S. S. Hender- 

 son, a transport built at the Philadelphia Navy Yard. Fig. 14, Plate 46, shows a 

 corner of the gyro room on the Henderson with the precession motor in the fore- 

 ground, and Fig. 16, Plate 47, shows the little control room with the rotary for gen- 

 erating A. C. current for spinning the gyros in the background. Directly in front 

 of the rotary converter is the vertical gudgeon bearing which transmits the sta- 

 bilizing moments through the ordinary steel decking to the ship's structure. This 

 ordinary steel decking is found to carry the stabilizing moments with a large factor 

 of safety. In the foreground is the special control gyro for the ordnance tests. 

 In this case the gyro may operate in a single period successively as a stabilizer or 

 as rolling equipment. Fig. 1 5, Plate 47, shows a curve of the Henderson automati- 

 cally rolled by her special equipment when at sea under full headway. 



This ship has operated with as high as 1 1,500 tons displacement, and the sta- 

 bilizer has been repeatedly operated under overload conditions without difficulty, the 

 journals running with perfect temperature control under the heaviest duty, includ- 

 ing overload conditions. Even different lubricants have been tried, all giving about 

 the same results; in fact, the plant, since the journals have been worked in, has 

 operated normally in service, and the records show that the guaranteed stabilizing 

 moments have been easily developed. 



Fig. 17, Plate 47, shows a plain gyro oil bearing that has operated perfectly. 

 This bearing has received over 100,000 precessions, many under overload conditions. 

 This bearing was removed for photographing. The original tool marks and scrap- 

 ing are plainly visible. Ths oil groove to the left, with its far end partially stopped, 

 and the corresponding diametrical one are the feeding grooves proper; the others 



