My father-in-law had this on his sailboat for that reason in northern Puget Sound BC. The Mounties gave him a box of barrier penetrating tear gas and instructed him to load the following rounds in this specific order:
1) Tear Gas - to be shot into the cabin or wheel house of offending vessel
2) Buckshot - to hose down the emerging pirates on deck
3) Slugs - to put holes in the hull below the waterline
Good Lord! What piracy is there in British Columbia???
Boaters in the Bahamas would encounter a boat that was supposedly "dead in the water" asking for help. While distracted by the person in the "disabled" boat, the accomplices would silently board one's boat from the opposite side and commence to rob, loot, and even rape and kill. Afterwards, they would either sink the boat to destroy evidence or take it back to one of the more remote islands in the Bahamas and repaint, etc., to disguise it.
This is why the stainless Winchesters sold like hotcakes at the time.
One of my customers brought to me for cleaning a nice little Colt .32 auto that had been purchased in London from Harrods (and so marked) but had been exposed to salt spray and had pepper marks on it. He was out on his cabin cruiser in the Florida Straits (in international waters) when he was accosted by a Cuban gunboat.
The Cubans held them hostage for a week, took all their food, water and medical supplies, allegedly raped a couple of the women and, ironically, threw the Colt into a towed dinghy before they left. And all of this in INTERNATIONAL waters.