Near the self-propulsion point in calm water, the time-average loads 
can probably be calculated with reasonable accuracy. However, even at 
these conditions, the variation of loads with blade angular position ap- 
parently cannot be calculated with high accuracy. Various techniques, 
including quasi-steady procedures, stripwise unstead procedures, and 
methods based on unsteady lifting surface theory, have been proposed for 
calculating the unsteady loading arising from the circumferential varia- 
tion in the inflow <gallaeiiey 5° However, all of these procedures require 
knowledge of the flow patterns (wake profile) in the propeller disk. In 
current practice, the wake profile is measured in the plane of the propel- 
ler behind the model hull with the propeller removed. For high-speed dis- 
placement ships of the type under consideration in this report, these 
results are usually extrapolated to full scale without making allowance for 
Srercusien, J.E., "The Development of Numerical Methods for the Computa- 
tion of Unsteady Propeller Forces," Presented to the Symposium on Hydro- 
dynamics of Ship and Off-Shore Propulsion Systems, Oslo, Norway (March 
UD TD) 
Tteon T. et al, "Calculation of Unsteady Propeller Forces by Lifting 
Surface Theory," Presented to the Symposium on Hydrodynamics of Ship and 
Off-Shore Propulsion Systems, Oslo, Norway (March 1977). 
eroddy: R.F., “A New Method for the Calculation of Unsteady Forces on 
a Marine Propeller," Presented to the Chesapeake Section of the Society 
of Naval Architects and Marine Engineers, Washington, D.C. (February 1977). 
aon Gent, W., "Unsteady Lifting Surface Theory for Ships Screws: Deri- 
vation and Numerical Treatment of Integral Equations," Journal of Ship 
Research, Vol. 19, No. 4, pp 243-253 (December 1975). 
psehwaneekes H., "Comparative Calculations on Unsteady Propeller Blade 
Forces,'' Proceedings of the Fourteenth International Towing Tank Confer- 
ence, Report of Propeller Committee, Appendix A, Vol. 3, pp 357-397 (1975). 
teeeciltim, J.P., "Propeller Excitation Theory," Proceedings of the 
Thirteenth International Towing Tank Conference, Report of the Propeller 
Committee, Appendix 2c, Vol. 2, pp 527-540 (1972). 
a rerreiele R.J. and M.L. Miller, "Unsteady Propeller Loading - Measure- 
ment, Correlation with Theory, and Parametric Study," Naval Ship Research 
and Development Center Report 2625 (October 1968). 
