"Marinas all over the state and indeed the country are being forced to be ADA compliant. "
It isn't just marinas, all sorts of commercial
buildings and operations, which have continued to ignore the issue for decades, are finally being forced to ante up. Usually changes are required if one of two things happens: If a "tenant" makes a request for reasonable accomodation, AFAIK it cannot be denied. And when a building owner makes a "major" modification, they're required to do all the new work up to ADA access standards.
If there are residences (liveaboards) in the marinas, I wouldn't be surprised if that tolled ADA requirements. If the docks were considered to be a public space, i.e. like a public beach boardwalk, again, there are trip points and when they are reached, all new work has to meet ADA spec.
Some of the compliance is sheer idiocy, like sidewalk cuts at intersections where they have cut both "sides" of a corner, leaving a 12" wide tripping hazard on the funny
angle standing between them. (OSHA would call that a tripping hazard.) Other times more sense has been used and the corner is simply beveled down, and that can solve a lot of access problems for a lot of people.
ADA requirements? A lot of them are pretty reasonable. Folks who step up and make their places more accessible and better compliant before they get ordered to do so, tend to have fewer problems and
ADA compliant wheel-chair accessible boat? Yeah, sure, I think that's called Carnival Line.