from everything I have seen and read, even though it is documented, boats still legally have to be registered in the state its in majority of the time

Depends on the state, as example mine is documented but not registered in KY. Each year I'm required to submit a tangible property form so KY can tax the boat in November. Failure to do so KY will charge a penalty and the tax. Most others with boats at the marina documented in other states do not pay the tax because KY doesn't know there location. There have been a small few which KY found out they are in KY and was hit with the penalty and back taxes

Other states are different

But it has to be in a no excise tax part of Montana, like Flathead county. Some areas of Montana will charge a personal property tax each year. The other bonus with MT is the plates are lifetime plates after the car is 10 years old. So buy a classic car, no sales tax and after the initial tag fee there are no more tag fees as long as you own the car!

Some states like California crack down on the scheme but Florida has so many out of town visitors they really don't care. I have a neighbor with a Suburban and a Range Rover with MT tags.........likely saved 10K in sales tax alone.

Absolutely not true, Documentation does not remove the requirement of state registration. the Federal law says that doccumented vessels must not display state registration numbers, it does not say that we should not or are prevented from registering the boat, (read this as paying sales tax). the state of Florida requires us to register the boat, which means paying sales tax, and displaying the annual Florida sticker with the year date on it, then each year they require us to renew that registration and pay the annual fee. Florida could not care less about the FL registration numbers, all they care about is the sales tax paid and the annual registration fee. Now guess how I became somewhat an expert on this.
we would all like to believe Coast Guard Documentation negates Fl registration and most of all sales tax. nothing further from the accurate facts.

Hey dickhead, read my post. I asked if he COULD document it and avoid the headaches. I'm aware that some states require registration as well. I'm not up to date on every state law, I was just offering an option to explore......