Taxes
In most cases, the tax (aka registration fee) needs to be paid in the state in which the boat will be kept (and primarily used) and not necessarily were it's purchased. For instance, if you purchase a boat in MD but do not intend to keep/use it in MD then you send a form in to MD DNR attesting to such and are therefore not liable for MD tax. It's called an out of state form. If however, you use/keep the boat in state and you think documenting will get you out of paying taxes, think again. There is a good chance that sooner or later they will find you and you'll end up paying not only the original tax but some pretty severe penalties. In most cases, when a boat's registration is changed from one state to another, credit is given for tax paid in the other state.