Nowaekt and Sharma 
m Oe he The eA 
pee Tor By = te 
Sista ae Syep HORE 
Cp = 0. 64 
ip = ip = arctan 0.4 = 21.8° (4) 
The absolute size of the model for the towing experiments 
was dictated by the size of the tank and equipment available : 
Like va nducO Selina keianaetere 
Bi itentdg gay ighe ature ey 
Tee nem Ons OOaun ae, OLOR 4. 
v = 0.3888 m”> = 13.731 ft? 
S = 3, AQG2i sane deste Shea (5) 
The choice of propeller was governed mainly by considera- 
tions of availability and simplicity. Fortunately, it was possible to 
borrow a very suitable propeller from the Hamburg Ship Model Basin 
(HSVA), namely a 200mm diameter model of the Standard Propeller 
recommended by the ITTC Cavitation Committee in 1960 for compara- 
tive testing, see Burrill (1960). It has a simple geometry (constant 
pitch, no rake, no skew) with accurately defined offsets (Figure 2), 
and performance characteristics were already available from previous 
tests at the Hamburg and other tanks. Its two-dimensional foil charac- 
teristics, however, were not known. The center of the propeller was 
positioned at 
Xp = t=O ile, 
= 0 
Yp 
=p =().05.0) an 6 
Zp (6) 
in the coordinate system of Figure 1. This arrangement relative to 
hull ensured complete submergence (0.75 D at rest) at all speeds and 
a low axial clearance (0.225 D) with accordingly accentuated interac- 
tion effects. 
III.2. Summary of Model Tests 
In accordance with the scheme outlined in Section 2 the fol- 
lowing model experiments were conducted : 
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