Nowaekt and Sharma 
The test procedure was to keep a constant rate of revolution 
and measure thrust and torque at various speeds of advance so as to 
cover the entire range of advance coefficient from the bollard condi- 
tion (J = 0) up to the zero thrust condition (J~P/D). A standardKempf 
& Remmers propeller dynamometer was used, The measured torque 
was corrected for bearing friction determined under identical test con- 
ditions with the propeller replaced by a dummy hub. No "dummy" hub 
correction'' was applied to the measured thrust. 
The Reynolds number for open water propeller test is conven- 
tionally defined as 
2 
nD Cc 2 z 
(E) =——  (~) Jot Oia) 
n 0.7Rp v D0 .( hs D 
with the design advance coefficient Jp usually approximated by 
O.75 P/D. Given the propeller geometry 
Dt=t0.12 ms, (c/D) oR =,0;, 328 2} “B/D =1 
and our test conditions 
Tia BS ce t= 69°F = 0, 9904. = Tigers. = 
it is seen that the Reynolds number was about 3.4 - 10°. This might 
appear io be barely sufficient to avoid scale effects due to laminar 
flow. However, we obtained satisfactory agreement with previous tests 
run at the Hamburg Ship Model Basin at a Reynolds number of 3.6° 
10-. By contrast, a test series run at the Institut fOr Schiffbau in 
Hamburg with the same propeller at a Reynolds number of 6.0: 10 
showed systematic scale effect at advance coefficients J<0.6, cf. 
report by Meyne (1967). 
A. 3. Self-Propulsion Test 
Special care was taken in the self-propulsion tests to ensure 
that test conditions were identical to those of hull resistance and pro- 
peller performance tests. The model was constrained in the same 
fashion as in the resistance test and the towing force was measured by 
the same instrumentation used for resistance measurements. The mo- 
del propeller was driven by an electric motor at predetermined rate 
of revolutions and thrust and torque were measured by the same dyna- 
mometer used for the open water tests. A streamlined tail fairing 
* This was the highest rate of revolutions possible without over- 
loading the propeller dynamometer in the bollard condition. 
1884 
