Similar for words like "ain't" and "y'all".
I could easily see someone in the US saying "this boat don't float", and believing they were being witty, or even just thinking it was the right way to say it.
2007 financial outlook - "The Krispy Creme (KKD) Donut Boat Don't Float" https://247wallst.com/investing/2007/06/04/the_krispy_crem/
Picture of a boat that actually doesn't float: https://www.deviantart.com/theuniphotoghrpher/art/This-Boat-...
Houseboat for rent: https://www.travelocity.com/Hartwell-Hotels-This-Boat-Dont-F...
Church sermon title: https://journeyorl.podbean.com/e/when-your-boat-dont-float/
Poem title: https://inprinthouston.org/event/first-fridays-presents-rebe...
2002 article about a Ford/Mercury car: https://www.deseret.com/2002/6/11/19659250/marauder-muscle-c...
Fishing forum: https://www.fishexplorer.com/co/fxrforum.asp?action=det&pid=...
Boating forum: https://forums.sailboatowners.com/threads/new-to-the-forum.1...
Australian website asking "What happens if your boat don’t float?" https://www.aussiemob.com/beer-can-regatta/