252 .6- 



Part 1» Discussion of the Results 



lo Preliminary Remarks * 



The present report Is concerned with the following 

 problem: what is the best location of a mine near the bot- 

 tom of the sea so that dxiring the secondary pulse the peak 

 pressure is a maximum? The result obtained Is; for weights 

 of 500 to 2000 lbs. of T.N.T. , in water of depth 100 to 

 150 ft. , the mine should be placed about 20 ft. above the 

 sea bed. More exact locations are contained in table 1, 

 p. 9. 



It is significant to compare different mine positions 

 as to their effects on the secondary pulse. This report demon- 

 strates that, during the secondary pulse, the highest possible 

 peak pressure at the surface is obtained when the mine is 

 placed in a definite "best" position. The theory indicates 

 that if the mine is placed even a few feet away from its 

 best location, the peak pressuj''e might be as -little as one- 



II n * 



half of that corresponding to the "best" location. F\irther- 

 more, when the mine is placed directly on the sea bed, experi- 

 mental evidence is available shov/ing that the secondary pulse 

 is weak and erratic. [9] 



Another point of interest is that the "best" position 

 also increases the effectiveness of the shock wave compared 

 with a location on the sea bed itself. In the latter case, 

 some experiments indicate that the presence of the sea bed 

 has no effect on the shock wave, and others, that it results 

 in an increase of about 12 percent in the peak pressure and 



* See the example discussed in section 4 below. 



