1110 
ABSTRACT 
Pressure-time curves from piezoelectric gauges located on the 
extension of the longitudinal axis and in the bisecting plane of 
Mark 8 Demolition charges (25 ft hose filled with 50 lb TNT) fired 
under water are interpreted quantitatively in terms of time phenomena, 
and qualitatively in terms of pressure time phenomena by consideration 
of the geometry of the experiment, detonation velocity (v), and 
velocity of sound in sea water (a). For gauges off the initiating 
end, (gauge position A) tp - ty = @(1/c + 1/v), where ty is the 
arrival time of the first signal to reach the gauge, tr the arrival 
time of the final signal to reach the gauge, and -@ is the charge 
length. For gauges off the opposite (non-detonator) end of the 
charge (gauge position B), tp - ty = 4(1/c - 1/v). For gauges in 
the bisecting plane (gauge position C), at small charge-to-gauge 
distances (rc) for which t,, the arrival time of the signal from the 
detonator end of the charge, is greater than ty, 
ty = (1/v) 42 + (xo/e) (v2 - 0) 
The arrival time of the signal from the opposite end of the charge is 
by otttets [0° oe An 
* 
Pressures measured by gauges in position B are 20-40% greater 
than those measured in position A, and those measured in position C 
are several fold greater. These are so compensated by the durations 
that differences in impulse in the various orientations are not 
significant. Shock-wave energies obtained from position C are several 
fold greater than for positions A and B, which do not differ 
significantly from one another. These relative parameters off the 
ends and side of a cylindrical charge agree with the recent 
theoretical results of Polachek, 10) and confirm earlier results 
obtained at UERL on somewhat more symmetrical cylindrical charges. 
* Superscript numerals refer to List of References at the end of this 
report. 
-vie 
