1898] SOME MORE ROWING EXPERIMENTS LOL 
APPENDIX I 
THE OAR USED AND CONSTANTS OF INDICATOR 
The axle of the Indicator is 1” below the button. Midway between the hands 
is 41°5” above this point, and the tip of the blade is 102” belowit. The centre of 
pressure of the blade was calculated on the rough assumption that the pressure at a 
point varied as the velocity, and it was further assumed that the turning point occupied 
its mean position 36” above the tip. 
The centre of pressure thus calculated is 9°6’ above the tip. 
Hence (see Fig. 13) 33184267" 
The instrument was calibrated against a spring balance, using a lever with a 
mechanical advantage of 3°07, and a series of experiments with the spring used 
throughout, showed 1’’ on diagram =319 Ibs. pressure or a pull of 220 lbs. 
The radius of the drum is 2’’02, so that 1’’ of base line on the diagram represents 
motion of /=1°71 feet. 
84 
Finally, 1 square inch of diagram represents 319 x a7 x 1°71 or 377 ft. lbs. 
APPENDIX II 
EFFICIENCY OF A STROKE IN ROWING 
Let 4 be ‘turning 
R point’ while oar turns 
D 1 B through an angle 0, 
B centre of pressure 
n _ A t of the blade, C the 
button, D centre of 
F P pull on handle of the 
Fic. 13.—Dimensions of Oar. oar. 
Work delivered to water=P x ABd@= ROA B do. 
Work done by man=#"CD d0= REF -CD dé. 
So assuming B a fixed point, 
[PAB me | __ 2RAB-A0 
= oe Spa BAG 
[RE de : 
Aé between successive positions of the oar was measured for all pairs of positions, and 
a curve drawn, from which corrected values were deduced. 
ft was measured in an arbitrary scale for corresponding values of @ on C, Fig. 7, and 
ABon Fig. . 
A table was then constructed as under :— 
Efficiency = 1 — practically. 
No. 6. | Ad. | 4B. | KR. | R-AB-AO.| RAO. 
x x x Oe. ill see) x x 
7 | 42°8 | 8-76 | 36-6 | 14:3 | 4580 | 125 
x x x ee et al x x 
Then by summation :— 
2 RAG=1049°7, BC=92 
LRA BAG = 32570 
eet 32570, 
eS) rues 
