I'm a California resident and have a California S Corp. I'm no expert (that's why I have an accountant), but I will add my 2 cents.
1. Mentioned above is the 800.00 annually that California charges. Yes, this is true, but I'm pretty sure that only applies to California corporations, not to corporations outside of California
2. If your boat is in California, even in a Colorado LLC, you will pay property tax. After a certain amount of time of paying property tax, you may be required to register your boat in California, even though it's in the Colorado LLC.
3. Though putting assets in LLCs is pretty standard, LLCs are, in fact, business. If an LLC isn't generating any income, it could be viewed as lacking a legitimate business purpose, opening up many cans of worms. An LLC whose only purpose is that it owns a boat may be well scrutinized
While you can save
money by doing what is mentioned above, and that's fine, I'm one of those people that has been hit with every freaking fine and action and doesn't seem to be able to get away with anything. So, I just pay what my accountant tells me to pay and in return, sleep like a baby at night.