274 STANDARD LUBRICATING OIL SYSTEM FOR GEARED TURBINES. 



in the paper or to be merely a difference of opinion, and, therefore, unnecessary to reply to 

 in detail. His condemnation of the system in general, as being unnecessarily complicated 

 for cargo steamers and in complying with practical requirements, comes under this head. 



Mr. Robinson's suggestion of an automatic by-pass around the strainers appears to us 

 to amount substantially to eliminating the strainers. The time element required to switch 

 from one basket of the strainer to the other is negligible. If the strainer should begin to 

 clog, the level in the gravity tank being used would naturally fall, and the engineer would 

 have warning of this fact both from the gauges, and, where they were installed, the auto- 

 matic alarm, and ample time to make the change. The twin strainers all carry a plainly 

 marked plate containing complete operating instructions. His suggestion that the heating 

 coil be eliminated from the gravity tank removes all operating control over the temperature 

 and viscosity of the oil before starting up. 



Mr. Wetherbee's comment, based on his experience, which we believe is almost entirely 

 with destroyers, therefore, is naval practice where the service is not continuous and where 

 operation is generally at reduced capacity. His success in building torpedo-boat destroyers 

 naturally gives him confidence in his ability as a designer, and his criticisms naturally merit 

 serious consideration. His sweeping statement that a system of such cost and complication 

 is absolutely unnecessary is, however, directly at variance with the opinion of other eminent 

 marine engineers, some of whom have had as much experience with merchant vessels as 

 Mr. Wetherbee has had with destroyers, and who passed on and approved every detail of 

 the standard system before it was issued. His prescription for keeping salt water out of 

 the oil is a part of the standard system. It is not, however, infallible, and even destroyers 

 have suffered from this trouble, as pointed out by Mr. Waller. 



This standard system was initiated by the failure of the simple pressure systems which 

 Mr. Wetherbee commends. We think his comments would be subject to much modification if 

 he were familiar with the character of operating attention which many merchant vessels re- 

 ceived during the war, and are still receiving. We had occasion during the war to ask Mr. 

 Wetherbee for some information regarding governors for marine turbines, and he replied 

 most positively that they were absolutely unnecessary. In the case of a turbine designed to 

 operate safely at 35 per cent overspeed and installed in a vessel subject to only' slight varia- 

 tion in draught we agreed with him, but a number of our vessels were equipped with tur- 

 bines which could not operate safely at 10 per cent overspeed and many of them had to re- 

 turn from France without cargo and without ballast except a small amount of water ballast. 

 As the turbines were equipped only with overspeed trip governors, which were not always 

 operative, there was great danger of damage to the turbine under these conditions, and we 

 disagreed with Mr. Wetherbee to the extent of standardizing a type of governor which 

 would prevent racing but would not shut the turbine down and yet permit perfect hand con- 

 trol of the speed. We believe Mr. Wetherbee would have done the same thing under similar 

 conditions. 



Mr. Anderson thinks that the pressure by-pass should not have been eliminated from 

 the system. In reply to^ Mr. Anderson we would say that the pressure by-pass was elim- 

 inated as being undesirable except as a war measure. In case of war it could be installed 

 quickly and at small expense. 



Mr. Waller's comments require only our thanks for his commendation of our efifort. 



The authors are glad that the paper elicited so much discussion, even though some of 

 the critics dissent from us in their opinions. 



