SHIP OPERATION AND THE SLEEP-WAKEFULNESS CYCLE 



331 



rouse sleeping men for the purpose of reliev- 

 ing the 16 to 20 o'clock watch section for 

 supper. It seems, therefore, that, of all 

 fighting ships, the submarine represents a 

 most favorable combination of factors con- 

 ducive to the estabhshment of a maintmned 

 shift in the sleep-wakefulness cycle. There 

 are, however, circumstances which militate 

 against this development, even on a sub- 

 marine. The chief among them are the 

 shore-type schedule of meals and recreation, 

 and the inability of the men to have an un- 

 broken stretch of sleep of more than 7 hours' 

 duration. Before suggesting remedies for 

 these unfavorable conditions, it was thought 

 desirable to find out how the personnel of a 

 submarine actually operated, and whether 

 the misgivings concerning the adjustment of 

 the men to a shifted cycle are justified. 

 Unfortunately, only anecdotal information 

 on the subject has been available up to the 

 present. To obtain facts and figures per- 

 taining to the several items of submarine 

 routine under discussion, it was arranged 

 for the writer to participate in a typical 

 cruise of the U.S.S. DOGFISH (SS 350) 

 and facihties were provided for collecting 

 pertinent data. 



The DOGFISH is a fleet-type submarine, 

 commissioned in 1946, but recently modern- 

 ized and converted to "schnorkel" opera- 

 tion. It departed from its home port, the 

 U.S. Naval Submarine Base at New London, 

 Connecticut, for the Bermuda Operating 

 Area on May 5, 1948, returning on May 21. 

 Two week-ends, spent at the U.S. Naval 

 Operating Base at Bermuda, broke the ship's 

 round-the-clock routine of operation. As a 

 result, only nine full to 24 o'clock periods 

 became available for statistical study, but the 

 significance of the mean figures obtained on 

 the duration of sleep is beyond any doubt. 



The personnel of the DOGFISH com- 

 prised eight officers and 66 enlisted men, 

 among them a rather high proportion of chief 

 petty officers (15). The ages of the crew 

 ranged from 17 to 39 years, with a mean of 

 25. They had served in the Navy from 



less than a year to over 18 years, and on 

 submarines as long as 14 years. The mean 

 of naval service of the crew was 7 years; 

 on submarines, over 4 years. Of the entire 

 personnel 43 were married and 31 were 

 single. By a self-appraisal of personality 

 schedule, it was found that 44 were pre- 

 dominately extrovert, 15 intermediate, and 

 6 predominately introvert (9 preferring not 

 to rate themselves). During the cruise each 

 member of the crew was interviewed by the 

 pharmacist's mate, who had the complete 

 confidence and good vnW of the men, as to 

 his habits of sleep, meals, recreation, etc., 

 both ashore and afloat, follo\\ing a definite 

 system of questioning (see Appendix). 



There were three watch sections. Section 

 I (2 officers and 16 men) had the 4-8 and 

 16-20 watches; Section II (2 officers and 

 18 men), the 8-12 and 20-24 watches; Sec- 

 tion III (2 officers and 17 men), the 0-4 and 

 12-16 watches; and what will be designated 

 in the figures and table as Section IV (2 

 officers and 15 men) was not required to 

 stand watches, but either followed a frankly 

 shore-type schedule of activities (cooks and 

 messmen) or were on call at all hours. Thus, 

 for purposes of comparison, the entire per- 

 sonnel was divided into four almost equal 

 groups. The hours of watches were fixed 

 for the entire cruise (except for the officers), 

 and the meal hours were made to coincide 

 with watch changes: breakfast at 7:30-8 

 dinner at 11:30-12, and supper at 19:30-20. 

 The late hour of supper made it unnecessary 

 to awaken Section II men in order to relieve 

 members of Section I for the 17:30-18 sup- 

 per, as is done on some submarines. But 

 light snacks were eaten prior to 16 o'clock 

 by a considerable number of men of Section 

 I, and also by members of Section III just 

 before midnight. 



To make the taking of records simple and 

 expeditious, a large sheet containing the 

 names of the entire personnel was provided 

 for each day's observations. In 24 boxes 

 opposite each name, the individual's activ- 

 ities were recorded by a code system which 



