Lewin's source was probably W. J. "Jasper" Holmes: 

 "Nearly twenty years before [i.e. around 1923], he was commander of 
 the Submarine School at New London when I was a student there.  Some 
 of my fellow students dated one of his daughters and reported that 
 she defended her father's strict discipline and exacting demands with 
 the statement: 'He is the most even-tempered man in the Navy. He is 
 always in a rage.'"  (W. J. Holmes, "Double-Edged Secrets", page 142) 

 Wilfred Jay Holmes 
 "Double-Edged Secrets: U. S. Naval Intelligence 
     Operations in the Pacific during World War II" 
 Naval Institute Press, Annapolis 
 Copyright 1979 
 ISBN 0-87021-162-5