Free Surface Effects tn Hull Propeller Interactton 
E 1) Measurement of bare hull resistance over the entire 
fedsiple speed ranpe of ‘0. ls °F, < 0.45. 
E 2) Measurement of propeller performance in open water 
(thrust and torque as functions of speed of advance and rate of revo- 
lutions) over the range of advance coefficient 0< J <1.2 at four depths 
of submergence : h/Rp =HS by 2.100, 1. 50° and» T;'00; 
E 3) Propulsion tests with the propeller operating behind the 
hull (measurement of thrust, torque and residual towing force as func- 
tions of model speed and propeller rate of revolutions) at fourteen dis- 
crete speeds corresponding to ¥, = 3.5 step 0.5 until 8.0 step 1.0 
until 11.0, and 12.5. At each speed the propeller revolutions were 
varied to obtain a sufficient range of loading usually covering both the 
model and the ship self-propulsion points (for an arbitrarily assumed 
model scale of 1:80). 
E4) Measurement of nominal wake in the propeller plane be- 
hind the hull (x, = -0.51 L) in both forward and reverse motion at 
three selected speeds corresponding to ¥, = 4.0, 7.0 and 12.5. At 
each speed the circumferential average of the axial wake velocity was 
measured by means of calibrated wake wheels at ten different radii 
R/Rp = 0.2 step 0.1 until 1.1. 
E5) Measurement of longitudinal wave profiles at a fixed 
transverse distance (Yo = 0.134 L) from the model center plane in 
two conditions ; 1) model with propeller running at ship self propul- 
sion point and 2) model with propeller replaced by a dummy hub, 
each at two selected speeds corresponding to ¥, = 4.0 and 7.0. 
Revelant details of the test procedure are given in Appendix A, 
III. 3. Hull Analysis 
Figure 3 shows the measured total resistance of the bare 
hull as a function of speed in the usual nondimensional coefficient 
form: Cp versus Fy, (or R,). Also shown in the figure are the ITTC 
1957 model-ship correlation line 
2 
Cp = 0.075 ‘a (log) gR,, - 2) (7) 
and the curve of estimated viscous resistance coefficient 
The latter is based on the Hughes form factor concept and determined 
from the measured total resistance at low Froude numbers by the gra- 
phical method of Prohaska (1966). Assume 
1853 
