Volunteer navies still trade training and mobility for service

How does modern all-volunteer naval recruitment differ from the US and Royal navies of the 1920s and 1930s?

The interwar navies were volunteer services too. The opening distinction concerns crew organisation, with social and educational changes explored in the follow-ups.

The initial answer emphasises that the interwar British and American navies also recruited volunteers. National service is therefore not the defining contrast with modern recruitment. Royal Navy personnel were organised through port divisions such as Chatham, Portsmouth and Plymouth. The wider changes in economic incentives and education are taken up in the follow-up debate.