From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Analysis of single versus multi-engined boats, comparing performance and power units with reference to Miss England and Miss Britain.
| Identifier | ExFiles\Box 174\1\ img009 | |
| Date | 22th November 1933 | |
| -2- which Mr. Scott-Paine proposes to build. Extensive trials can then be made and a new engine can be decided later after reviewing the results. (5) The power available in the "R" engine was given as 2300 H.P. at a max. speed of 3200 R.P.M. We discussed at some length the relative merits of single and multi engined boats and compared the analysis of results on many types of boats. The figures appeared to show that the chief factor in increase in speed lies in increased horse-power per unit of engine weight. For example, Miss England II and III were tried out with the same engines and the speeds were within one mile an hour. When the new engines were fitted to Miss England III the top speed was 120 and calculations indicate that with these engines fitted Miss England II would do somewhere about the same speed. Gar Wood's boat is reputed to have done 124 M.P.H. with four engines giving a total power of over 6,200. There is thus no indication that we can anticipate a considerable increase in speed by merely multiplying the number of power units. It is also significant to note that the speeds of the multi-engined boats are round about the same figure but each have their own features and are designed by different people. The inference is that all these boats have the same characteristics when planing along the water. Comparing the Miss England I with Miss Britain III, both single engined boats, the former giving a speed of 92.5 M.P.H. with 920 H.P., I calculated that its speed would be 104.5 M.P.H. when fitted with the latest Lion engine now in Miss Britain III. This agrees very well with Mr. Scott-Paine's estimate of 105 M.P.H. which he states he has already done. In estimating the speed therefore at 125 with the "R" engine, we virtually eliminate assumptions since our method of calculation has been proved to be true on the analysis of performance of numerous other boats. It was therefore considered desirable to concentrate efforts on the single engined type of boat and carry out trials to a final issue. The advantages of adopting this course are :- (a) The experience already gained on this type of boat can be utilised, whereas it would mean practically starting again on a multiple engined boat. There would also be more chance of applying improvements which Mr. Scott-Paine has in mind to reduce the resistance of the hull. | ||