709 
II, GENERAL DESCRIPTION OF GEAR usepL/ 
1. Vessel and cquipment 
The RELIANCE was a 76-ft Gloucester—type fishing schooner converted in- 
to a research vessel, equipped with an electronics cabin and a mechanical- 
gauge cabin, as well as the necessary sources of power for the work to be 
done. A two-way radio telephone and a recording fathometcr were a part of 
the standard equipment, In addition to these scientific accomodations there 
were a galley, quarters for the crew, and a general workshop (Figs. 2 and 5). 
Deck space was available for the necessary gear and other equipment, 
including a large power-driven reel for the piezoelectric-gauge cables. 
2. The "one-dimensional" fore and aft rig 
Practically all of the work in comparing explosives was done by locat— 
ing the various gauges used on a straight line fore and aft through the 
charge and parallel to the surface of the water (Fig. 3). At the after end 
of this line was the sea anchor uscd for maintaining tension, In the middle 
was located the charge, while the forward end of this line was attached to 
a tow line leading up to the vessel RELIANCE, The gauges and charge were 
usually hO £t below the surface and were suspended from surface floats. 
These components were attached to one another by means of the stecl spacer 
cable which was kept stretched out by the strain of the sca anchor as the 
gear was towed through the water. Electrical cables for firing and for 
transmission of piezoclectric-gauge signals back to the electronics cabin 
were led to the surface and thon to the RELIANCE by mcans of a surface line 
supported by special floats. 
3. The "two-dimensional" paravane rig 
A great disadvantage of the "one-dimensional" rig was that it allowed 
measurements to be made for a single charge in only two dircctions that 
were opposed by 180°, To obtain a measure of the explosion field in four 
directions from a charge, the two-dimensional or paravane rig was developed 
(Figs )). As with the one-dimensional 1ig the gauges and charge were sus— 
pended at the same fixed depth below the surface, with a line running from 
a sca anchor at the aft end of the gear through the charge to the tow line 
leading to the RELIANCE, In addition to this part of the gear, which is 
the same-as. for the one-dimensional rig cited above, there were also gauges 
mounted on two lines that were attached to the charge at an angle of 90° to 
the fore and aft line. These side lines were held out by means of two 
paravanesé. attached to the gauge blocks at the ends. 
There are many difficultics inherent with thisparavane gear. It must 
be set in perfect balance, otherwise the paravancs do not behave properly 
Te nl fe rou an ete Ive 
2/, paravane here refors to a flat surface so suspended that it pulls 
out and down as it is towced through the water. Opposing these two forces is 
the force from the opposite paravane and the force upward duc to a surface 
DUoYye 
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