My current bath fans exhaust through the roof, which kind of takes up a lot of valuable upper deck space. Has anyone seen a bathroom exhaust fan that is more like a residential fan that I can exhaust through the side wall?

I have about 4 inches of height in the roof joist so it can't be too tall.

I have 110 volts available on the boat, but would rather run the fan at 12 volts for efficiency and to use the existing 12v wall switch and in-wall wiring.

If worse comes to worse, I could build my own with computer cooling fans. Still an off the shelf fan would be a lot easier.

Does anyone have experience buying or building a bathroom exhaust fan?