Interesting question and not at all 'dumb'...
So I sent the thread over to a surveyor, since she has inspected and documented hundreds of vessels over the decades.
No surprise in her common-sense answer, but perhaps worth sharing (IMHO). Her surveys are renown for being detailed and a valuable learning tool/guide for new owners... i.e. Lots of good detail and very little boilerplate.
"Not a dumb question at all. My very intelligent opinion (and I am a Very Stable Genius) is the same as yours in one respect, and that is that all (99.999%) boats are owner modified. But, as owners, we certainly have that right. And, there is no license or special training that anyone is required to have to show competency.
The best analogy is a home owner. Nearly all (99.999%) are owner modified. And, much like boats, home building is very much a cottage industry with thousand of builders building millions of different homes. Homes are different in only a small way from pleasure boats and that is that major modifications on homes within certain jurisdictions require permits and some inspections to confirm the modifications met existing codes.
In boats, like off-road cars, there really are no standards or applicable regulations. And, as long as the person performing the modifications or repairs is not charging for their services, I know of no cases where a private individual lost in court for a substandard modification if the modification was made in good faith. Boat owners are not even bound by good-faith disclosure to the best of my knowledge.
If substandard repairs are performed by a business, then there is liability attached. The rule of thumb used in court is the ABYC standards and USCG regs. Don’t be cutting standards if you are profiting from your work.
A person who could (and should) be held liable, is the dirtbag who buys a wreck of a boat and flips it by only making cosmetic repairs and hiding the damage. I have seen hurricane total loss boats that were sold as salvage, transported across the country, polished up, some cheesy repairs made, and resold for a huge profit. The unlucky buyer is left with a boat requiring more repairs than it is worth or has a failure that results in injury or death. There is liability lurking there.
Hopefully the potential buyers have a good surveyor on their team.
Of course, this is America. People sue anyone for anything. So, it doesn’t matter what you do or don’t do. Just by breathing, you put yourself at risk. So, have fun, modify your boat to put a smile on your face. The risk will always exist to some degree whether you do or don’t."
