OF SUBMARINES BY MARBEC'S METHOD. 265 



DISCUSSION. 



The President: — The paper of Professor Hovgaard on "Calculation of the Trans- 

 verse Strength of Submarines by Marbec's Method" is now before you for discussion. The 

 Chair by no means wishes to speak irrelevantly, but he desires to refer to something which, 

 in a measure, is connected with earlier Transactions of this Society. A paper of this kind 

 requires a great deal of work. The incorporation of such papers in the Proceedings of our 

 Society is exceedingly valuable for our Transactions are really encyclopedias of naval archi- 

 tecture and marine engineering data. I know of many who consult the earlier volumes to 

 obtain information which is very important in their later professional work. 



Therefore, while a paper of this kind may not elicit discussion, it is of very great value, 

 and I am sure that you will desire that the thanks of the Society be tendered to Professor 

 Hovgaard for his valuable contribution. 



Professor Hovgaard (Communicated) : — I wish to point out that this paper is not 

 merely of academic interest. The problem of the strength of submarines is an actual and 

 practical problem, as will be admitted by those who have to design such vessels, as also by 

 those who have to operate them and whose lives depend on their strength. The calculation of 

 transverse strength is of enhanced importance after the introduction of depth bombs, which 

 makes it necessary to design submarines to stand the pressures at much greater depth of im- 

 mersion than formerly. It is a problem which the designer of submarines cannot escape. 

 The method here proposed differs from those previously used in its greater simplicity and in 

 being graphical, allowing the results to be more clearly exhibited. The numerical example 

 is purposely chosen so as to cover a very general case, i. e., that of a section with only one 

 axis of symmetry. Where two axes of symmetry are found, the calculations will be very 

 much simplified and the elegance of the method will be more apparent. It is the first time, to 

 my knowledge, that a complete numerical example has been given in illustration of Mar- 

 bec's method, facilitating its application in practice. The paper is written primarily for this 

 purpose, that is, for direct application in practical work. At the same time, the proof of 

 the method is presented in what I believe is the simplest and most direct form. 



If the best result is to be obtained in the construction of modem submarines, it is neces- 

 sary to make scientific calculations in conjunction with experimental tests. In this way the 

 Germans effected very considerable savings in the weight of the strength hull of their sub- 

 marines during the war. 



The President : — ^We have now come to the end of our morning program. Immedi- 

 ately after adjournment there will be a brief meeting of the Council. We will now stand ad- 

 journed until two o'clock. 



Adjourned. 



