I wasn't there and only know the perspective presented by the OP. I don't know that I'd do anything differently -- I wasn't in those circumstances. That said, some of the commentary posted leads me to a couple of conclusions. First, different people view certain dialog/phrases/words VERY differently -- some perceive such as benign and others as provocative (non-escalating vs. escalating). Second (and this point has been made by others), according to the OP's account the boat owner seems to have purposefully re-engaged. In some ways this could be considered an escalation in and of itself. Last, the warning given, "You won't get the chance to sit up straight", seems to have been effective in that a gun-fight did not break out. While giving the warning could be perceived as an escalation point, the warning may also be added information that may change the recipient's actions.
All in all, I am glad it worked out without extra paperwork, time and inquiries.