Hi,
I saw this movie around the early 80s. This journalist (?) ends up on an island thing. Maybe not an island but somewhere remote and with a gate to the outside.
Anyway, there’s a family living in this remote place and they take him in and he discovers that the mum and dad are brother and sister.
The climax is when the father uses a cannon (don’t know why he had a working cannon) to kill the family bc he thinks the visitor will dob them in.
Maybe something like that, I was pretty young and that was a long time ago.
thanks 🙂
There’s The Island (1980), but it doesn’t quite match all of your description… https://en.m.wikipedia.org/wiki/The_Island_(1980_film)
Oooh I wonder if my 8 year old brain saw that! It does match a lot of it – I’d not remembered gangs of pirates though. And I thought the scene with the cannon was near the old house not on a boat. I hope that’s it bc it’s sillier than my terrified memories. Thanks 🙂