The United Kingdom's Navy is experiencing a big manpower shortage brought on by years of intentional recruiting shortfalls. As a result the British approached the U.S. to help fill the gaps, but the needed help came from the Coast Guard not the Navy.
The first time the Royal Navy used American Navy personnel it resulted in the War of 1812. Now, more than 200 years later, the discussion is much more amicable. Coast Guard Commandant Adm. Paul F. Zukunft explained the situation at a recent event:
This is what happened the first time the UK started using U.S. troops on board its ships. (Library of Congress)