were larger for the stern-up condition than for the stern-down condition; 
the largest value occurs at (UP yp =1-85 degrees or time=0.31 seconds in 
the reference of Figure 19. This suggests that the effective speed of 
advance of the propeller increases slightly for the stern-down condition 
and decreases slightly for the stern-up condition. This appears reason- 
able since for stern-up the propeller tends to be further into the bound- 
ary layer of the hull. However, the time-average value per revolution did 
not monotonically increase with increasing ~ for all components. 
For dynamic simulation the largest absolute value of the time- 
average value per revolution of all loading components, except spindle 
torque My» occurs at approximately 0.15 second after the condition 
WV oy) =0> W>0, which is the reference for time t=0 in Figure 19. This 
indicates that the maximum time-average value during dynamic simulation 
occurs at a value of hull pitch angle ~ which occurs 0.16 second or 0.1 
cycle, before the » at which the maximum time-average value occurs during 
quasi-steady simulation. 
There was a significant difference between the peak values for the 
quasi-steady simulation and the unsteady simulation. For the quasi-steady 
simulation, the variation of the peak values with hull pitch angle yp 
followed approximately the same trends as the variation of time-average 
values per revolution. These quasi-steady results indicated that for 
V-Voy up to 1.85 degrees, the maximum increase in the peak value of any 
loading component above the corresponding value for vv oy was 5 percent. 
For the dynamic simulation, however, the maximum value of the peak loads 
increased as much as 23 percent above the corresponding value for steady 
ahead at a fixed hull pitch YVoye 
The dynamic simulation exhibited a dramatically different trend of 
peak load with ~ than was indicated by the quasi-steady simulation. For 
the dynamic simulation, the largest value of the peak loading, for all 
components except spindle torque My» occurred at approximately time t=0.8 
second in the hull pitch cycle shown in Figure 19. This corresponds to 
w=1.5 degrees stern down during the portion of the cycle in which the 
stern is moving down; i.e., (-Voy=-1-5 degrees, t<0. For dynamic 
35 
