How to contact someone in the Navy after they change assignments?

I'm trying to get back in touch with a friend of mine whose email address I have is from his old ship so the address no longer works. I've tried finding out ways to contact him but have had no luck. I'd love to be back in touch but I don't know if it's possible to get his email address now. Any ideas?|||Mail a letter to him, at his old ship. It will be forwarded to him at his new command.|||All services have a Military Locator number. Contact a Navy Base Operator