John Frayn Turner's Periscope Patrol, John Jordan's Warships After Washington, and Norman Friedman's British Submarines in Two World Wars provide complementary views of the subject. Official treaty declarations could be politically managed, and contemporary references such as Jane's depended on information navies chose to release. Friedman provides a consistent statistical baseline across the submarine classes covered here. Apparently precise warship figures still need provenance and comparison before they can be trusted.
Notable Point · 2:38-5:14
Reading official submarine figures critically
Published displacement figures and contemporary naval reference books require source criticism because navies controlled much of the information they released.