While your idea is good in theory, I'm not quite sure that it could be made a reality.
But other than that, I can't really argue with your thoughts on this. The thing that would concern me is the following:
If said enemy was to kill you, (not ship) would you automatically return to duellism? Or would you remain off of it until you ship or said person leaves the walls?
Just my thoughts,
Written by my hand on the 7th of Midsummer, in the year 1217.