THE MAINTENANCE OF THE FLEET. 115 



The Chairman : — We now pass to the next paper, No. 10, entitled, "Period of Vibra- 

 tion of Steam Vessels," by Mr. William Gatewood, Member. We will be glad to have 

 Mr. Gatewood present his paper in person. 



Mr. Gatewood : — I want to apologize to the Society for presenting a paper containing 

 so many mathematical formulae, and for two reasons: First, there are few who really 

 enjoy mathematics; and second, the mathematics in this paper is of the vintage of over thirty 

 years ago, and the bottle has been left micorked and possibly it is a little bit sour. 



There have been read before the Society several papers on the subject of balancing 

 engines, but, so far as I am aware, nothing has been read before the Society relative to the 

 effect of the unbalanced forces of the engine on the structure of the vessel. So I have taken 

 this opportunity of presenting a few thoughts on the subject. Almost everyone has experi- 

 enced the discomforts of the vibrations of steam vessels, and some of you, perhaps, have 

 experienced the discomforts of the vibrations of the Ford motor car. I am at liberty to 

 mention the Ford car, because it has a close relation to some classes of war vessels. 



When the turbine installation was first put into vessels, it was considered that the dis- 

 comforts of vibration would be eliminated. It was found, however, that while they were 

 greatly reduced, there were still some vibrations left. It is possible that, when the elec- 

 tric drive is perfected, the vibration of steam vessels will be further reduced. 



As is well known, in all calculations relative to the strength of vessels, the vessel is con- 

 sidered as a beam and the stresses are determined by the beam formulae. So it seemed to 

 me only natural that the period of vibration of a vessel could be worked out by considering 

 the period of vibration as that of a beam. I have therefore presented to the Society some 

 statements relative to the laws governing the period of vibrations of beams, and the appli- 

 cation of these laws to the case of a floating vessel. 



Mr. Gatewood then presented his paper. 



