Did submarines ever make Great White Fleet-style voyages to test long-range operations?
Short answerThey made long deployments between friendly bases, but public international cruises would have revealed too much about submarine range.
NotesNavies tested submarine endurance by deploying boats between their own bases. They did not need a public international voyage comparable to the Great White Fleet. Such a cruise would reveal how far the submarines could operate and therefore expose a wartime capability. Quiet domestic deployments provided training and range evidence while preserving operational uncertainty for potential opponents.