To meet the goal of increased bottom time and more rapid ascent, both mechanical and

biochemical problems had to be overcome. Under pressure, the density of air increases and

impairs breathing by reducing the mechanical efficiency of the lungs. Divers’ bodies absorb

more air under pressure than at the surface. Atmospheric pressure doubles with each 33 feet of

depth, and with each doubling the volume of gas is reduced by half. The longer the diver is

down, the more compressed air circulates through his system. When the pressure decreases upon

ascent, the gas expands. The diver must rise in stages to allow the blood to circulate and air

escape slowly in a process known as decompression. Rapid decompression leads to the

dangerous condition known as the “bends.” Decompression tables established safe rates of

ascent. Then, decompression chambers allowed divers to be brought up quickly, repressurized,

and decompressed slowly while at the surface. Other divers could continue the job during the

process. Consequently, the ability to function in confined quarters became an important

requirement for divers.

The fundamental physiological concern was to provide divers’ bodies with levels of oxygen that

would sustain life while reducing gases whose volume underwent significant changes with

changes in air pressure. By altering the gas mixtures divers breathed, both depth and bottom time

could be increased, so various gas mixtures were tried. Oxygen is toxic at high levels and results

in convulsions and death; as the pressure of the gas goes up the percentage of oxygen must

decrease. Divers with high oxygen tolerance have a distinct advantage. Carbon dioxide is also

toxic, and materials to absorb the excess gas were inserted in helmets. Nitrogen has a narcotic

effect at depths beyond 100 feet, so a replacement carrier for oxygen was sought. Helium

tempers the taste buds, causes dehydration of the sinus cavities, and, because its thermal

conductivity is greater than that of air, carries heat away from the diver’s body. It also comes out

of the system more slowly than nitrogen and affects the vocal cords resulting in the “Donald

Duck effect.” Nevertheless, the problems associated with helium proved to be the most amenable

to solutions, and helium-oxygen mixtures that had been developed by the Navy decades earlier

were widely used in oilfield diving by the late 1960’s. The high cost of helium led to efforts in

the 1970’s to develop rebreathers that would recycle the gas and to efforts to replace helium with

nitrogen.

Divers worked in confined spaces at high pressure, lived for up to several weeks at a time in

close quarters, and took risks relying only on the word of supervisors and company doctors that

new methods were safe. Every new invention required additional human capacities and

experimentation on divers, and many innovations were motivated by injuries and deaths. Still, as

each new innovation came along, divers could be found to try it out. Macho pride, the desire to

be the first, prospects for higher pay, and a love of diving all played a role:

I like the gas work. I quit doing anything above 150 feet of water. Greed

overcame my fear. You could go down and work an hour or two and you would

get paid more than you spent working a week in some waters (Daspit, personal

communication, 2002).

[Being in diving] a long time starts to define who you are almost (Taylor, G.,

personal communication, 2002).

Problems with heat were addressed through the use of suits that were heated either by surfacesupplied

hot water or electric wire. Hot water suits were preferred even though they initially

scalded the divers; divers reported that they would leave the front of their suits open to allow

cold water to mix with the heated water coming from the surface.

The introduction of new gas mixtures meant new mechanisms for generating and then delivering

those gases to the divers; standard air compressors were no longer adequate and gas mixtures had

to be purchased from elsewhere. Significant invention and innovation accompanied the

development of diving masks and helmets. One of the first Navy artifacts to be modified for

oilfield work was the Mark V helmet, which had been developed prior to WWI and remained in

use until the 1980’s. The helmet and full diving suit with which it was used weighed as much as

200 pounds. Working in the Gulf of Mexico around rigs and platforms, divers needed flexibility

and the ability to climb up and down, in and out among platform legs and tangled pipes. In

addition, divers were frequently given a small area on the barge from which to work; in this

space they had to cram their air compressor, tanks, radio, and everything else they brought along.

Masks that were originally designed for SCUBA were adapted for use with hoses and

compressors because they were smaller and used less air; however, the lack of any head

protection was a disadvantage in construction work. Beginning with the end of WWII, Gulf

Coast divers acquired access to Japanese helmets, and these became popular among some divers.

By the 1960’s, several Gulf coast divers had designed and built their own hats. Walt Daspit, who

was motivated by Joe Savoie to design and construct his own hat, describes why:

The first guy that came out with a lightweight diving helmet was Joe Savoie. We

were working on one of McDermott’s barges with Chuck Gage and we saw Joe.

Joe was explaining to us what he was going to build. He was going to use an

aqualung, which was a sterile diving dress that was used at the time. It was a

front entry and you would wrap up tight and you would stay dry. Joe was going

to put a neck ring on it… He wanted to build a helmet out of a race car crash

helmet. Then he was going to the faceplate visor and a neck ring and tie it. He

was explaining that to us and drawing it. I said, “Joe, you can’t do that because