272 



TEMPERATURE AND HUMIDITY 



There is little danger from 3 percent CO2 

 and 12-14 percent O2 for a brief period before 

 ventilating the boat. The 1928 article 

 discusses the phj^siological principles which 

 are concerned with the most encomical use 

 of materials to absorb CO2 and replace the 

 O2. Economy is important in a long cruise 

 and in case of a two or three day submer- 

 gence can add another day of life while 

 waiting rescue. 



In Dr. Hoff's Bibliographical sourcebook 

 the subject of air purification is brought up 

 to date. The older method of removing 

 CO2 by soda lime in canisters has been 

 replaced by lighter and more efficient 

 absorbers, but some of these are caustic and 

 not without hazard. Oxygen is still sup- 

 phed from heavy tanks. More experiments 

 are needed to show the best methods of 

 absorbing CO2 and providing oxygen. 

 There have been marked improvements in 

 the transport and use of liquid oxygen. 



Although rough estimates can be made by 

 calculation as to the time when it is neces- 

 sary to start removing CO2 or supplying O2, 

 these should be supplemented by air 

 analyses. A good many years ago the sub- 

 marines were provided with a simple method 

 of carbon dioxide analysis contained in a 

 little box. As far as the writer can tell the 

 apparatus was seldom used in the Pacific 

 during World War II. If submergences are 

 to be prolonged air analysis is imperative in 

 order to economize materials and retain the 

 efficiency of the crews. Even though the 

 apparatus is simple it must be inspected and 

 tested frequently. Great accuracy is not 

 needed but the method should, for example, 

 be able to tell whether the CO2 is 2% or 

 3% and the oxygen 16% or 17%. 



The danger from hydrogen can be con- 

 trolled by adequate battery ventilation, but 

 there may be emergencies in which the gas 

 approaches a concentration that is explosive. 

 Elaborate electrical detection apparatus is 

 accurate only if it is in perfect order and 

 calibrated against known mixtures. 



Arsine and stibine may in rare instances 

 cause trouble if arsenic and antimony are 



present as contaminants of battery lead. 

 The tests for them are simple. Chlorine 

 is generated if sea water gets into the bat- 

 teries. Fortunately the alkaline absorbent 

 of CO2 also removes CI2. 



Carbon monoxide may cause serious 

 trouble with any new type of fuel or engine. 

 Here again the tests are fairly simple. The 

 effects of poisoning by carbon monoxide are 

 so insidious that a commanding officer would 

 have little warning before complete disaster. 



The odoi*s in submarines, particularly after 

 long submergences, cause great annoyance. 

 The chief source of odor is the human body, 

 but the smell of smoking, cooking, garbage, 

 and the venting of sanitary tanks make 

 heavy contributions. Each factor should be 

 studied by itself and at the same time there 

 must be efforts to absorb or counteract the 

 whole spectrum of stinks. Apparently char- 

 coal as an absorbant has been disappointing. 



The food on submarines, well discussed in 

 a recent article by Shilling and Duff ^ has been 

 on the whole satisfactory. There is still the 

 problem as to the method of securing ade- 

 quate ventilation of food, especially meat, in 

 ice boxes in order to have maximum capacity 

 without danger of spoilage. 



It is to be hoped that the engineers will 

 be able to make improvements in the light- 

 ing and painting of submarines. They could 

 probably secure more space for personnel if 

 they redesigned some of the bulky instru- 

 ments and controls. Snorkeling will tend 

 to eliminate some of the exposure on the 

 bridge in cold and stormy weather, but there 

 is still the crying need for clothing that will 

 keep an officer warm and dry. 



The snorkel, on the other hand, has in- 

 troduced its own problems. The sudden 

 fluctuations of pressure are hard on the ears 

 and sinuses and the effects of long periods 

 below the surface have not yet been explored 

 thoroughly. Every new type of submarine, 

 engine, fuel, and oxygen supply must be 



3 Shilling, C. W., & Duff, I. F. Analysis of 

 submarine food problems in world war II. U. S, 

 nav. med. Bull. 1948, 48, 683. 



