Captain and Mrs.....
The title "Captain", or the abbreviation CAPT would be appropriate. The salutation in a letter might read "Dear Sir" or "Dear CAPT Smith". When a politician or military officer retires, he's allowed to use the form of address of the highest rank held.
Thomas Arnold - Navy captain - was born in 1679.
Thomas Arnold - Navy captain - died in 1737.
A Royal Navy Captain is the same as a United States Navy Captain - it's the equivalent of a full Colonel in the armies of both countries. The next rank up is Commodore - Brigadier equivalent.
John Knatchbull - Royal Navy captain - died in 1844.
My uncle, the retired U.S. Navy Captain, decorated his home office in a nautical theme which included several wooden model sailboats and portraits of antique Navy ships.
No, the equal rank in the Navy or Coast Guard is a Captain.
Frederick Lewis Maitland - Royal Navy captain - died in 1786.
Frederick Lewis Maitland - Royal Navy captain - was born in 1730.
Hugh Pigot - Royal Navy captain - was born on 1769-09-05.
Hugh Pigot - Royal Navy captain - died on 1797-09-21.
John S. McCain was a Captain in the United States Navy before he entered into politics.