204 THE PROBLEM OF THE HULL AND ITS SCREW PROPELLER. 
H+B=.305 ES OR AUG ATEN NCUNI SMM. 10,670 
B. C. on C—D corrected for ae 455 THO RY SE AIA AUR SN SHE 2,904 
5. B. C. on X =.49 | Cie A aR PROM SDC BES 84 
2L. A. B.+H=109.5 LANL SI URE AAAS 0 BIR Gye Ca) 
Si WE AT AT ere dat al io ea ee a 8.75 
1 GEM Ba OPN oy Beata e Vil 4 5 Ul SO ea tlt 31,732 
Mean T. C. Large TEAM Oa a Nace A MPR EO aUANI aA 554 
iKSii 1 B31 (Ad Ea ane eRe ca 17,580 
PS) ik] Pa eae Mae ERR aA ec) 29,196 
Analysis. 
SIM ail 7 a Zp K ce Zs | Sian ei” 
Ene if Est. | Act. Est. | Act. 
1 | 1758 | 10.31 | .4273 | —1.0414]1.0| 2654] 2750] .98 | .16| .139 | 148 | 153 
2 | 3516 | 12.96 | .5371| — .7279 | 1.0] 5463 | 5400| .68 | .16 | .143 | 187 | 189.5 
3 | 5274 | 14.81 | 6138 | — .5445| 1.0] .8333 | 8100] .515 | .16 | .149 | 215 | 218 
4 | 7032 | 16.3 | .6755| — .4144 | 1.0 | 11244 | 11050 | .400 | .16 | .158 | 240 | 241 
HS, 8790) | ed7e 440) 7228) |) 3t35e (ed ON Ad g5e | ds 700) | e307) elon) 1Gt | 25ia nose 
6 | 10548 | 18.42 | .7634 | — .231 | 1.0 | 17152 | 16300 | .250 | .16 | .167 | 274 | 274.5 
7 | 12306 | 19.32 | .8007 | — .1613 | 1.0 | 20138 | 19150 | .19 | .16 | .171 | 288 | 288.5 
8 | 14064 | 20.1 | .8350] — .1009 | 1.0 | 23143 | 22000 | .142 | .16 | .176 | 302 | 302.5 
9 | 15822 | 20.7 | .8579 | — .0477 | 1.0 | 26159 | 25300 | .11 | .16 | .185 | 314 | 315 
1.0 | 17580 | 21.13 | .8757 | — .00 | 1.0 | 29196 | 28300 | .082 | .16 | .193 | 324 | 326 
1.05 | 18459 | 21.3 | .8848 | + .0221 | 1.0 | 30720 | 30000 | .075 | .16 | .200 | 329 | 331.5 
Concerning the efficiency of propulsion, results of trials indicate that with 
type 1 and probably very fine type 3 ships, where the basic slip is greater than the 
S values corresponding to curve B, Fig. 7, there is a gradual increase in efficiency 
in passing from the upper curve of S to B and then a gradual decrease until the 
cavitating curve for the basic Sis reached. However, in making the estimates of 
performance, this probable increase should be omitted and carried as “so much 
possible velvet.”’ The maximum gain is probably reached with basic slip between 
21 and 22 per cent, becoming practically zero with those basic slips for which the 
upper S curves on Fig. 7 approximate closely to B or are below B. 
WAKE GAIN AND LOSS. 
Before taking up the subject of design, there is one phenomenon met with to 
which attention should be called, and this is the effect produced by a change of 
