Landweber 



DISCUSSION 



H. Lackenby 



The British Ship Researah Association 

 Northumberland^ England 



I certainly agree with Professor Landweber's plea for a more 

 detailed study of the relatively thick boundary layers in way of ship 

 sterns especially in very full tanker forms. 



In Ref, 17 (Shearer and Steele) it is apparent that some of 

 the models of the full tanker forms considered were suffering from 

 gross separation at the stern. There is little doubt that this accounts 

 for the viscous pressure resistance being as high as 30% of the total. 

 Incidentally, in this reference the corresponding wave making re- 

 sistance or gravitational component was stated to be only 3 to 5% of 

 the total. 



Reference is made in Professor Landweber's paper to con- 

 ditions which bring about separation but not, as far as I can ascer- 

 tain, to methods of calculating the shear stress after separation and 

 the added pressure resistance which this brings about. I would be 

 glad if the Author would care to comnnent on the development of 

 calculation methods for these conditions. I would also mention that 

 In some of the latest full tanker forms there Is little doubt that 

 separation is taking place on these ships at sea and the situation Is 

 having to be accepted. 



The viscous component of ship resistance has always been 

 an Important one but owing to the developments In tanker forms It 

 Is becoming even nnore Important than It was in this class of ship. 

 Professor Landweber's paper Is, therefore, of particular Interest 

 eind importance at this time and I look forward to further develop- 

 ments In his approach to the problem. 



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