Depending on your skill level and the type of networks available, I'd look at the MikroTik Groove. I've written a lot about it and you can find some of the articles at
https://seabits.com/?s=mikrotik
It's relatively inexpensive, and can source both 2.4Ghz and 5Ghz WiFi signals. It is not simple to configure, though, so if that is a desire, you're stuck paying 2x-5x for a 2.4Ghz only product, but that may be enough depending on your situation.
However, many marinas, two of which I am working with actively today actually, have massive issues with 2.4Ghz WiFi signals and their members being able to utilize them without switching to 5Ghz. I wrote about that a few years ago at
https://seabits.com/marina-wifi-hard/ and it's still applicable, if not even more-so today.
I'd say about 75% of the folks I work with have abandoned marina WiFi, and gone full LTE, but that opens up a whole additional set of things to deal with - SIM cards and data limits and boosters and expensive routers. If you can get local WiFi and boost it to an internal cheap router, that's the cheapest and easiest way to do things.