Underwater explns

Fovershom Mixture, called by Daniel Fulmi-coton Nitrati de Faversbam, consisted of NC 51.6 Ba nitrate 48.4%. This compn was practically the same as Tonite No 1, patented in 1874 in England by Trench, Faure Mackie, which contd NC 51 Ba nitrate 49% There was also Tonite No 2, which contd as the 3rd ingredient charcoal and Tonite No 3 (patented by Trench in 1889), which contd NC 14.55 to 19.00, m-DNB 13.20 to 13.00 Ba nitrate 72.25 to 68.00%. Some of these mixts were manufd in England, Belgium and USA. The compn of Belgian mixt was NC 50, Ba nitrate 40 saltpeter 10%. These mixts were suitable for underwater explns and some of them were used for loading torpedoes... 

Later they proved to be very effective for underwater explns. Two Penthrinits, 1 2 of Table 17 were, accdg to Stettbacher (Ref 6), loaded in 1929—1930 in 2cm shells and tested at Oerlikon Fabrik at muzzle velocity (vQ) 840m/sec. No prematures occurred. The addition of about 15% A1 powder increases the efficiencies of Penthrinits, while high amounts seem to decrease it. For example, addition of 30% A1 to formulation 1 of Gelatine Penthrinits decreased detonation velocity from 8000m/sec to 7200... 

The effects of underwater explns are of obvious interest in naval warfare since they determine the performance of sea mines, depth charges, torpedoes, etc. Some discussion of the military effectiveness of underwater explns will be found in later sections of this article. Underwater expln phenomena are also important in non-military underwater blasting. Here it often becomes important to minimize damage to nearby underwater structures rather than to destroy them... 

Study of underwater expln has also contributed appreciably to a better understanding of detonations and detonation effects. For example, underwater expl studies have elucidated the transformation of the chemical energy of the expl into other forms of energy such as shock... 

The theoretical aspects of underwater expln will be considered in Section VII... 

With the qualitative illustration of observable shock and bubble parameters shown in Fig 5, we can now proceed to a description of the test methods used to obtain such data. Figs 2 5 immediately suggest the use of pressure transducers to follow the pressure-time histories of underwater explns. Similarly Fig 1 (bottom portion) suggests the use of visual (photographic) techniques to obtain dimensions and positions of the gas bubbles. Indeed, these are the major techniques now used in studying underwater shock and bubble effects... 

Bjamholt (Ref 21) examined the routine determination of underwater expln parameters. 

From a practical point of view, it is important to determine how the chemical energy of an underwater expln is partitioned at various distances from the charge and how much useful work can be realized from such an expln. The pioneer efforts to answer these questions are summarized by Cole (Ref 1, Chapts 4 8). 

Bjarnholt and coworkers (Refs 13 and 21) used a semi-empirical approach to estimate the useful energy of HE via underwater expln energy measurements. In essence, their approach involves computation of a shock toss factor, ft > 1, to estimate the shock energy at the HE/water boundary from measured shock energies at some distance from the HE. This is coupled with the assumption that the measured bubble energy at some distance from the HE equals the bubble energy at the HE/water boundary. Then the total underwater expansion work per unit mass of HE, A0, is given by ... 

During WWII some Al powd was incorporated in Bonits and this increased their efficiency for underwater explns. The Swed aluminized expls were, according to Stettbacher(Ref 2), more efficient than the Get underwater expl of WWII, which consisted of TNT 55.7, HNDPhA 27.9 ... 

NAVORD Rept 73-46 (1946) (New short-time underwater expln gage) 27a)Muraour (1947),... 

Fig 16 (Bomb of Krupp-Schmitz) 84-90 (Detn of pressure by means of Vieille s bomb) 28)J.F.Moulton J S.McCorkle, NAVORD Rept 400 (1947) [A short response time mechanical gage (SRT Gage) for measuring underwater expln pressures] 29)P.Slavik,... 

Cole, Underwater Explosions (1948), 146 -98 [Various devices for measuring underwater explns pressures. Included are ... 

The max effect for underwater explns was obtained with 79% K chlorate and 21% NB. This effect was equal to about 108% of Dynamite No 1 (NG 75, kieselguhr 25%). The charge was... 

Nokelit.. See under Swedish permissible expls Nobel s Safety Powder. Same as Guhrdynamit Novit a)TNT 60 HNDPhA 40% and b)TNT 55.7. HNDPhA 27.9 A1 powder 16.4% used for underwater explns [Ref 25b, p 107 and A. Stettbacher, Protar9, 38 41 (1943)]... 

Ballistic Mortar 2) Trauzl block 3) Underwater explns and 4) one method — cylinder expansion — that is now used at Lawrence Livermore Laboratories... 

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