To avoid just such cases, which obviously had a demoralizing effect on the rest of the crew, the submarine service worked out a tightly meshed screen to sift out the men most susceptible to mental collapse. Some years back, Captian C. W. Shilling, wartime head of the United States Naval Research Laboratory at the Naval Research Base, New London, Connecticut described the formula. First, the Navy doctors agreed, the emotionally mature volunteer made the most level-headed sub man. After interviewing thousands of volunteers, they drew up a list of danger signals which invariably pointed to instability. Then they designed tricky tests to ferret them out.
Mothers often put heavy pressure on their son to withdraw from training.
In some cases, mothers were interviewed by the Navy doctors, and if they found the son was being unduly influenced by her fears, he was usually dropped from training. Navy psychiatrists found that teen-agers often could not measure up to the maturity requirement of the service. Finally the Navy refused to take a submarine candidate under 19. Sub-service men were picked from the top half of the Navy's intelligence scale and from men in top physical condition. Despite this pre-screening, however, up to 30 per cent were turned away after careful psychiatric examination.