World War II intervened and halted all 

 thoughts of peaceful research. 



At the commencement of WWII the follow- 

 ing state-of-the-art existed in military and 

 other undersea circles: Diesel-electric sur- 

 face-powered military submarines were oper- 

 ating at a maximum depth of 312 feet and, 

 under normal conditions, stayed underwater 

 some 20 hours using what air was in the boat 

 when the hatches were closed. Lithium hy- 

 droxide was scattered throughout the sub- 

 marine for carbon dioxide absorption if the 

 situation warranted. Ambient-pressure div- 

 ing, i.e., where the diver is exposed to sea 

 pressure and not inside a pressure-resistant 

 suit or capsule, had progressed to the stage 

 where 243-foot dives, breathing helium-oxy- 

 gen, were a practicality (4). Earlier subma- 

 rine disasters in 1925 (USS S-51) and 1927 

 (USS S-4) demonstrated the need for devel- 

 opment of better diving techniques and res- 

 cue devices. In conjunction with the Bureau 

 of Mines, the U.S. Navy's Bureau of Con- 

 struction and Repair began investigations 

 into all aspects of prolonged deep-diving at 

 ambient pressure. This work progressed to a 

 point where an Experimental Diving Unit 

 was established in Washington, D.C., in 1927, 

 which went on to develop chambers for res- 

 cuing trapped submariners, as well as de- 

 compi'ession tables and gas mixture for di- 

 -vers. The benefits of this research paid off in 

 1939 when the USS SQVALVS went down in 

 243 feet of water off the Isle of Shoals in the 

 North Atlantic. Forty of the trapped crew 

 were rescued by the newly developed rescue 

 chamber and with the assistance of divers 

 breathing helium-oxygen. 



Ambient pressure diving up to 1943 was, 

 BATHYSPHERE-Wke, tethered to the sur- 

 face for support in the form of air and verti- 

 cal movement. Devices did exist for the diver 

 to carry his own oxygen or air supplies, but 

 oxygen is toxic at depths greater than about 

 35 feet, and the compressed air device, in- 

 vented by a French Naval officer. Com- 

 mander Le Prier, in 1925, released a diver- 

 regulated, continuous fiow of air into a face 

 mask which, by design, imposed very short 

 diving limits. 



In 1943 another French Naval officer, 

 Jacques Cousteau, teamed with engineer 

 Emil Gagnan and produced the demand reg- 



ulator to provide air from tanks only when 

 the diver inhaled and automatically in- 

 creased the air pressure to equalize pres- 

 sures inside the body with water pressure 

 outside. The demand regulator and the imag- 

 inative artistry of Cousteau later produced a 

 revolution in the field of recreational and 

 commercial diving. 



With the close of hostilities, Piccard once 

 again asked for, and received, the pre-war 

 funds allocated for FNRS-2. Fl\RS-2 served 

 as the prototype for all future bathyscaphs. 

 Its purpose was to dive deep (10,000 ft origi- 

 nally), allow the passengers to view outside, 

 range about the bottom and to do so with no 

 cable to the surface and with a wide margin 

 of safety. 



In many respects, FNRS-2 was a reversal 

 of the principles which made FNRS soar. The 

 pressure sphere, with a W/D ratio greater 

 than 1, would sink unless restrained; the 

 Professor constructed an oval-shaped, thin, 

 metal-walled float wherein six compartments 

 held 6,600 gallons of gasoline which, being 

 lighter than water, would float and hold the 

 cabin (Fig. 3.3) at the surface.* Gasoline was 

 valved off by the pilot to begin the descent, 

 and water immediately replaced the gasoline 

 to maintain a pressure within the tanks 

 equal to that without. FNRS-2 carried sev- 

 eral tons of iron shot in steel tanks which 

 were restrained from dropping by doors held 

 closed with electromagnets. In the event of a 

 complete power failure, the doors opened and 

 dumped all shot. Similarly, other tanks held 

 scrap iron and gravel for additional ballast 

 which also jettisoned in the "fail-safe" man- 

 ner. The iron shot could be dumped incre- 

 mentally to slow down descent or increase 

 ascent. A 7-foot-long cable attached to the 

 sphere held a 100-kilogram (wet weight) flat- 

 iron-shaped concrete clump which served to 

 hold FNRS-2 in stable equilibrium just off 

 the bottom. 



Instead of a cable to the surface, FNRS-2 

 carried its own power in the form of two lead- 

 acid storage batteries which ran two 1-horse- 

 power motors (mounted port and starboard 

 at the base of the float). External lights were 

 provided for viewing and a carbon dioxide 

 removal system and oxygen were carried 

 within the pressure sphere. The motors 

 served to provide a measure of horizontal 

 maneuverability for bottom exploration. 



36 



