IR Camera Over Water?

I see, I presumed this was for when the boat was in the slip or at the dock. Considering water is essentially dynamic, and the atmosphere surrounding a boat can range from still/clear to turbulent/foggy, I think any camera using visible/IR spectrum range will be challenged. Do you project the camera being mounted on a stabilizing positioner to counter the movement of the water? Not inexpensive, but without it it can be near impossible to keep a view of even nearby objects.

With no actual experience mounting IR cameras on a moving boat, I'll digress. It is an interesting and challenging prospect.

It will work OK over water, shouldn't be that much different than any other illumination source in terms of how it behaves.

Your main issues (IMO) will be coverage area, you usually want a fairly wide FOV for applications like that, and then selecting a camera that allows you the really tweak the exposure settings so that the overall image brightness and contrast stays somewhat stable through minor lighting changes and doesn't become distracting.

I think you'll also have issues with range for this setup. It's usually not the things that are 50' in front of you, it's the things 500' in front of you that you want to be on the lookout for at night. Thermal cameras are good in this application because you can see farther (typically), but (again, IMO) the fact that they are looking at heat, not light, helps maintain a more stable image at night.