Can anyone give me a good reason to paint under the floorboards? I can't think of one, and unless someone can give me a reason I don't plan to. It's not just laziness or the extra time it would take. I think of the area under the floorboards as structurally crucial and if I ever have need to inspect under there paint could mask any damage or potential failure. Even sanding would make things more difficult to see.
The most expensive and nicely fininshed house will have pretty crude-looking crawl spaces and I doubt the furnace room will look all that great. I have of course never been on an expensive yacht, but my guess is the engine room or space is nowhere near as pristine as the cabins.