Charge Weight W in pounds 



380 



occur Is assumed to be equal to 

 the sum of the maximum radius 

 and the rise to the time of the 

 first peak. The results are 

 shown in Figure 6. 



The migration caused 

 by the proximity of a surface, 

 in the absence of gravity, is 

 shown in Figure 7 on page l6, 

 expressed as a fraction of i^g- 

 The combined effect of gravity 

 and a vertical wall for a sin- 

 gle small charge is shown in 

 Figures 9 and 10. Curves for 



estimating the rise of the gas globe under a free surface and above a rigid 

 horizontal bottom are given in Figure n and 12 respectively, page 20, for a 

 wide range of charges. 



In Figures 15 and l6 on page 26, the two components of migration, 

 vertical and horizontal, are given for the combined effect of gravitation, a 

 free surface, and a vertical wall. As the weight of the charge Increases, 

 the gravitational effect is shown to predominate; thus the downward motion of 

 the globe from a small charge is reversed with an increasing charge in the 



Figure 6 - Curve Giving a Rough Estimate of 



the Minimum Depth Dm below the Surface 



at which a Charge W may be Detonated 



without Blowing through the Surface 



before Undergoing Recompression 



Distonce from Wall Z in feet 



Figure 9 - Upward and Horizontal 



Components of Displacement of 



the Gas Globe from 3A Ounce 



of Tetryl or TNT 



The charge is assumed to be detonated 10 feet below 

 the surface of the water, far above the bottom, and 

 Z feet from a rigid vertical wall. The curves show 

 the displacement from the point of detonation up to 

 the point of greatest recompression, according to 

 approximate calculations. 



""O 2 4 6 8 10 12 14 16 18 20 

 Height above Bottom in feet 



Figure 10 - Displacement of the Center 



of the Gas Globe from 3A Ounce of 



Tetryl or TNT, up to the Instant 



of Maximum Recompression 



Detonation is assumed to occur at the height shown 

 above a rigid horizontal bottom in water 20 feet 

 deep. Positive ordinates represent a rise, negative 

 ones a descent. The curve is based on approximate 

 calculations. 



