Morgan and Caster 



DISCUSSION 



V. Silovic 



Hydro- og Aerodynaniisk Laboratorium 



Lyngby, Denmark 



The interaction between the ship and the propulsive unit plays an important 

 part in the case of a partial duct. In this case, the open-water results and avail- 

 able theories are of little help. Do the authors have any comments ? 



DISCUSSION 



Gilbert Dyne 



The Swedish State Shipbuilding Experimental Tank (SSPA) 



Gothenburg, Sweden 



This is a very interesting paper and it illustrates in a striking way how 

 astonishingly few the experimental verifications of the theories are, especially 

 for ducted propellers. In fact, a closer examination shows that the stringent 

 verifications are still fewer than what they first seem to be. I would like to 

 make some comments on this fact. 



The results from two different theoretical approaches to the problem have 

 been described in the paper. These approaches are set forth in Table Dl. It is 

 common to all theories mentioned that the total thrust (or propeller thrust) and 

 the advance ratio are given, while the duct thrust and the pressure distribution 

 along the duct are determined. 



Table Dl 



1346 



