Got my "Legends of the High Seas" through and I have had a bit of a look. - It's a Warhammer Historical production.
The foreword says it was inspired by the "Legends of the old West", and I have that too. It looks like the rules are very similar too.
They were based on Mordheim with some LotR stuff thrown in - you have 'Fame' and 'Fortune' points like 'Might' and whatever .................
144 pages + cover - rules for fighting with pirates, privateers, island natives and the navy, both on land and at sea. I haven't gone into the ship movement or fighting rules yet, but so far I am impressed.
What I like is that I don't have to buy any models - I can use any of my Empire or DoW minis, and the only difference is that they are on 20mm square bases rather than 'round' as shown in the book.
I doubt it will make a scrap of difference.
I think the author may be american - there is a pic on the inside back cover that shows the inside of a small fort - made form Hirst Arts blocks

Some of the land buildings shown are not too far away from use as Wild West buildings, so again scenery can be dual purpose.
Now I just need to build a boat or two .............