More than 60 days and you have to pay use tax. However if you paid sales or use tax in another state and can show your receipt, you will not be dinged again for up to the amount you paid to the other state. If the other state is equal or greater you're good, otherwise you need to write a check for the difference. BTW -- RI has no sales or use tax on boats, so that's where you want to be in New England if from out of area.