.....IF you ever bring it back in state they'll ask for sales/use tax and fines and penalties going all the way back to the date of purchase. Nasty.........
hs, I've read the story of your friend that had this happen. I am not familiar with a State that has a use tax that triggers on the date of purchase. I don't know them all, for sure, but have needed to learn several over the years.
You are generally guilty until proven innocent. When you come forward in your home state, even years later, many will require the original bill of sale. When they see that date, you will have the burden of proof that it hasn't been there all along. How many keep marina contracts for years? That had to be the problem.
Some states will grandfather goods purchase in the past, and not charge use tax. While CA is not a state I'm familiar with, from another post, it appears they have an annual personal property tax. Makes sense for a state like that to grandfather goods that you purchased and used out of state, to incent you to bring them home and pay a lifetime of pp tax. After a period of time, you clearly have the option to keep and use the goods elsewhere.
Nevertheless, this is probably all moot for the OP. It seems that they live, purchased and used the boat in CA. There is likely no way out. I fully agree with the mafia reference. Sales tax collectors are always more aggressive than income tax collectors, by far! They are typically going after merchants that fail to turn over the taxes they collected. That is equivalent to stealing, as it wasn't their money in the first place. Makes them very jaded.