TURBINE STEAM YACHT WINCHESTER. 71 
Estimated R.P.M. Actual R.P.M. Per cent of error 
992 1030 3.69 
947 972 2,575 
899 912 1.425 
854 854 .000 
806 625 
759 932 
707 427 
662 915 
-495 
18 
Mr. STEVENS (Communicated) :—I regret to say that as I am not in possession of the 
data referred to by Mr. Anderson, I am unable to give any information on this subject. 
In answering Lieutenant Robinson’s remarks, it is true that by using the actual shaft 
horse-power the revolutions obtained by the analysis work out much nearer the actual revo- 
lution than they do by using the estimated horse-power. However, I am not prepared to 
fully accept the reason stated for the discrepancies at the lower speeds, as there are several 
chances for errors which I will enumerate. 
First, the effective horse-power with appendages was estimated by taking the bare hull 
estimated horse-power (from tank trials) and multiplying it by 1.09. 
Secondly, the runs on the progressive trials were made (as can be seen by examining the 
table) as follows:—Six at top speed and only two runs at each of the following —about 
24.4 knots, 18.5 knots and 10.71 knots. 
Thirdly, I have been informed by the builders that the torsion meter cards at the lower 
powers were very small and too much reliance should not be placed upon their accurateness. 
I do, however, believe that there is a large amount of truth in the reasons stated by Lieu- 
tenant Robinson, although I do not think that they are the whole cause for the differences 
at the lower powers. 
Before closing, I wish to thank the Society for the interest taken in this paper. 
Tue PrEsIDENT :—Is there any further discussion? If not, I am quite sure that you 
will agree to my extending to Mr. Stevens the thanks of the Society for this paper. 
As was called to the attention of the Society a couple of years ago, Mr. Stevens is the 
son of one of the founders of this Society. There are not many sons of founders at the 
present time who have developed as has Mr. Stevens. We are very glad indeed to hear from 
him. 
We will now proceed to paper No. 7, entitled “Theory of Fluid Friction,’ by Mr. W. 
Gatewood, Member. 
