Think Wizard Chess meets Monty Python and you'll have a rough idea.
The "Cap'n" got to make an additional rule after each capture of a "royal" game piece, that's also my recollection. My dad hated to lose. LOL.
There were also rules about needing to state "Yer in check, matey" in a good Pirate-voice, too.
The loser had to sing a pirate song on some occasions. There were also songs to remember the moves and strategies that I (at 3-5yo) was being taught, as well. I do recall that.
My father was an interesting person, as is probably obvious. But this was WAY before any cute YouTube instructions existed for anything. Before cable TV, actually. He did teach me basic chess rather well using this method.