Our boat is a solar panel. We have four house batteries and 700W of solar in the sunnier months in the UK that powers the fridge, a freezer, two macbooks, internet etc.
Full summer it produces around 2kWh a day. When it’s clear and sunny even with our standard house draw we see up to 20A pushing into the system. We use a renolgy monitor that has a shunt, cheap and effective.
I’d recommend putting them on any flat surface you can. We use the flexi renology ones. Pretty good value and well protected for weather.
We’ve found them essential, no matter what the state of the battery in spring / summer / autumn if the batteries are a little low and the engine isn’t wanting to start by 10:30ish everything is fine.
As a recommendation I’d suggest you get a MPPT controller rather than one of the cheapo options. The numbers on the charge controllers denote max voltage / max ampage of the solar system.
For voltage you probably don’t want over 80V ish on deck. For amps, if you can try to get around at least double what you need. Solar is addictive. Once you have one you’ll want another.
Winter it’s pretty pointless and I’d agree that a wind gen is the way forwards. We’re fitting a Rutland 1200. The other ones are heavier and produce less juice so if you can worth going for the higher spec option.