In 1945 the submarine was a surface torpedo boat which could submerge for protection. There is at least one World War II submarine patrol r·eJ..tort which de:sc·r·ibed a remarkable 38-hour dive to escape a depth charge attack. But routine dives lasted only 12 to 18 hours. Moreover, during daily surfacing, the submarine’s engines were started and within five minutes the boat would be full of fresh air. Except as an emergency consideration, no one worried about carbon dioxide removal, the replenishment of oxygen, or the control of air contamination. Heat was also of little concern. Calculations indicated that a fleet submarine needed about 20 tons of air conditioning. Yet, the Bureau of Ships saw fit to provide only 8 tons of capacity — and everything seemed to work fine.
In 1956 the NAUTILUS made an 11-day dive. And by 1959 the u.s. had a true submersible. Dives of two week durations were routine, there had been several 30-day dives, and one 60-day dive. It was the SEAWOLF in October 1958 which completed the 60-day dive. To evaluate the state of “atmospheric control now requires about 60 pieces of equipment”. A presentation included tlte following report:
“In October 1958 SEAWOLF completed a submerged cruise of 60 days, completely divorced from the earth’s atmosphere. The cruise was made by a highly motivated crew using jury rig equipment; however, ostensibly it was quite successful. No one died or became ill, everyone apparently performed at peak efficiency and there have been no reported after-effects.”
In reality, by 1959, carbon dioxide removal was a routine problem which was being taken care of on a continuous basis by a C02 scrubber while the oxygen supply was no long~r an emergency consideration but a commodity routinely supplied like food.
Work on the C0 2 scrubber was started during World War II by the National Defense Research Council. By 1940 Mare Island Naval Shipyard had developed a scrubber for use on ‘·.he PERCH and SEA LION two battery powered sul arines (!Or•verted to troop carriers.
By 1959 the M . H. Treadwell Company was supplying the Submarine Force with high pressure, mono-polar, electrolytic oxygen generators. The oxygen generator concept was conceived in 1953 when it was established that the nuclear submarine, with its extremely long submergence periods, was nearing a reality. At that time, three general methods for making oxygen were available: air distillation, chemicals, and electrolysis. The first method, while the most efficient, was not practical due to the limited amount of air in the submarine; and the second was considered unattractive since it made the submarine dependent upon logistic support. The third method, production of oxygen and hydrogen by electrolyz .ing distilled water was selected as the best method since the required inputs — water and electric power were readily available on nuclear submarines.
Because of the high pressure of 3000 psi used in the electrolysis of water process, and because of the possibly explosive nature of the products, oxygen and hydrogen, the early system was protected by 56 safety devices and would shutdown and blanket itself with nitrogen at the detection of any malfunction. The Treadwell oxygen generator, now iiJ!proved but still I’E~cognizable to old hands, continues to provide oxygen to submarine crews today.
What does the future hold for submarine life support? New technology may totally change the methods of oxygen supply and carbon dioxide control while additionally providing a significant improvement in overall operational capability.
Aquanautics Corporation, a biotechnology company, has demonstrated the feasibility or ext.racting dissolved oxygen from sea water. Their process is based primarily on the way biological sy.stems remove oxygen from air• or water. The difference is that the oxye.en is produced by an electro-chemical procesa in much the same way as hemoglobin is unloaded from blood. The Defense Advanced Research Project Agency is currently funding Aquanautics to produce a simple underwater vehicle propelled by a fuel-cell which uses oxygen extracted from the seawater through which the vehicle moves. The demonstration, scheduled for the fall of 1987, will demonstrate energy efficiency and compactness.
The technology will likely reach fruition -the real question is when.
Military applicatiori~ for underwatt>r power, pr·opulsion, and life support are limited only by tl!e illlagination. As to the source of oxygen for submal’i ne life support, there has been only modest intAt·e~.:t to date, primarily bt>cau~P t.h£·r-e i~. no c;perat:i.or 21 requirement, i.e., a \o/Orkable system oxi::t~. Some inter·est has been ~l,cwP by those concerned with submarine security who worry about discharging the hydrogen by-product or electrolysis. It may be timely for imaginative Navy people to consider this new technology and investigate its many possibilities.
Aquanautics Corporation l•as also developed a schen,e to reu:ove carbon dioxide from the air and change carbon dioxide gas to carbonic acid for discharge overboard as a fluid. This scheme might in time be used to discharge combustion gases -as a liquid — significantly reducing the back pressure of discharge and the noise of underwater systems which use theroJal combustion for propulsion.
What might the environmental control systems of a submarine look like in the 21st Century? Oxygen for breathing might be removed directly from sea water much as fish do it. There may no longer be hydrogen to worry about with its high pressure purges and potential explosions. The carbon dioxide concentration could be held constant to 0.03 percent by volume — for an entire patrol. and its discharge as a liquid would be qujet and simple. Atmosphere control will not only have come full circle — with no one worrying about it — but the Navy may start getting complaints from submarine sailors \olho \o/Orry about the effects of the foul air they breathe while on liberty.
Richard R. Pariseau