In the second week we were introduced to scuba, which stands for self-contained underwater breathing apparatus. We used the older-style double hose regulators, which convert the tank's high pressure air to the air pressure of the surrounding water/air, and give it on demand. The right hose was for inhalation, the left for exhalation, and the exhaled air exited into the water at exactly the same spot as the diaphragm which controlled the inhaled air. Captain Jacques-Yves Cousteau and Emile Gagnan had patented this process in the 1940's, just after WWII, and the regulator we used was only a second generation design away from the one he originally marketed.
We learned how to disassemble, clean, repair, reassemble, and test the scuba gear. We knew it backwards, and forwards, inside out. Interestingly, some of the regulators had black housings, and the interior parts were plated with gold rather than chrome-plated steel. The reason was so that they were anti-magnetic...
...The compass courses were open water swims. At first, they were minimum equipment, meaning a life vest, mask and fins with booties. Our fins were Navy issue ones with a blade about a foot long and stiffening ribs. They were of a open heel design, which allowed us to carry them easily, but the heel strap was solid rubber, without any type of adjustment. The blade was as stiff as plywood, so these fins were hard to push through water. But they did give us good acceleration when we needed it.
The two things that the U.S. Navy instructors at the Underwater Swimmers School in Key West impressed upon us was the buddy system and the masks on the forehead. "Who do you think you are, Mike Nelson?" they'd yell if they saw a mask on the forehead. The idea was that the mask on the forehead is in an ideal position to be washed off by a wave.
The open water swims started at 500 yards, and progressed to 1000 yards, then to 1500 yards. Means and I did well on the initial swims, and never became separated. This was important, because if a team was seen in the water and out of arm reach, they had "broken buddy contact" and were penalized. The penalty: carry a "buddy line" for 24 hours, only the buddy line was an eight-foot long piece of rope, 4 inches thick, off one of the ships. The negligent buddy team even had to sleep with this line...
We progressed in our training to open water scuba. One dive, in the harbor, tested our ability to function in near-zero visibility. We were given a tool bag, and each buddy team had to go to the bottom of the harbor and assemble a flange with bolts and nuts in the zero visibility water. When we surfaced, we were to hand the assembled flange to the instructor. Means and I waited our turn, then stepped off the pier into the brown water. It was cool, but not cold, and the water seemed to allow us to see about three feet. Then we dove to the bottom, and as we swam deeper, the light penetrating from the surface disappeared, until at the bottom, in forty feet of water, we could not see a thing. I handled the bag, and gave Bob each part. He placed them in the holes, and I felt for the holes on the opposite side of the flange. Then Bob pushed a bolt through, held it while I found a nut to attach. Soon, and the flange was assembled. We followed the safety line to the surface and handed the assembled unit to the instructor. We had passed easily.
From the manuscript, Between Air and Water, the Memoir of a USAF Pararescueman, Copyright 2014, John C. Ratliff