Marine audio is the specialized field of installing electronics, specifically stereos and video components, on boats. This is most common for wakeboarding and sport boats, but it can also be an option for jet skis, fishing boats, and yachts.
Water-resistance and proper installation are two key points.
In terms of sound quality and features, typically anything that can be installed in a car can be installed in a boat, it’s just a little harder due to the harsh marine environment.