I have only openly carried in Alaska (often going ashore in areas where there are many grizzly bears, but I also carried bear spray, large size. I also took many other precautions against serious bear encounters). In Guatemala, I openly carried, with the permission of the federal military--that was for the safety of my family. In both bases it was a S & W SS 629 in appropriate caliber. Oh yes, many years ago, I used to openly carry in California...a lifetime ago, when backpacking.
I have been in foreign countries, where it seemed prudent to have arms aboard and available if necessary--mostly due to drug runners. Unfortunately one does not always get to choose who shares an anchorage, and at times it may be dangerous in several ways to leave, other than when the light is high in the sky.
I would be very cautious about taking arms on a "Great Loop" Voyage, since there are several states, and areas which you will pass thru, which take a dim view of many types of weapons.
Both Marie and I are CCW holders. I frequently carried when I was in practice, because one of the hospitals was in a "bad" area, and I also made house calls. Several of my associates were badly injured--two to the extent they were not able to continue the practice of medicine, by an assailant. I also believe in very careful situational awareness. No one would ever know that we were carrying.
As for a shotgun, we may carry a Mossberg 500 in blued steel, which is kept well oiled. In retrospect I might have purchased a SS version--but at the time many years ago, it seemed like more than I wanted to pay. That Mossberg is about 45 years old, and is just as functional as the day it was purchased.
I certainly agree with proficiency. But 2500 rounds a month?--seems excessive, and I suspect was somewhat tongue in cheek. I doubt that I shot that many rounds a month when I was on the pistol and rifle team, and shot during noon hour almost every day... That would have been over 100 rounds a day....
Be safe!