Dredging up an old thread here, but this seems like the place to put it...
I'd like to know who aboard ship would be a "Mr". Was there a set rule? Like, you had to be higher than a warrant officer or something? I gather the surgeon's title is a little fuzzy, & could be either Mr or Dr aboard ship, even if he's just a "Mr" ashore & not actually a "Dr".

But, what about the bosun & sailing master? These are the 2 I'm particularly interested in. Would they ever be addressed as Mr? Would the captain call them just by their surnames?

(For what it's worth I don't recall ever seeing any indication that the captain could be addressed that way by any of the crew.)

All commissioned sea officers, except those in overall command like captains, were gentlemen by definition, and would have been called ‘Mr’. So would the Warrant Officers of wardroom rank who were seen in terms of responsibility, education and background to being the equivalent of gentlemen, that is the Purser, the Master, the Surgeon and the Chaplain (though the last two would have been called ‘Dr’ if the first was a university trained Physician and the latter a Doctor of Divinity.) Others who were being groomed to be of wardroom rank (and were possibly of ‘gentlemanly’ origins), like the Clerk, the Midshipmen and the Masters Mate’s, were also called ’Mr’ and were allowed to ‘walk the quarter deck’- ie when at leisure.
The three remaining senior Warrant Officers were artisans and overwhelmingly of humble origin, that is the Boatswain, the Carpenter and the Gunner. None of these were regarded as gentlemen, did not mess in the wardroom, were not entitled to ‘walk the quarter deck’ and could not have complained if they were not referred to as ‘Mr’. However their ages, importance and experience meant that they were most certainly addressed as such as a matter of courtesy and respect.

Brian

Just what I was looking for. Thank you