if its on navicable waters and has a motor on it, regardless if its used or not, it must be registered... 8 foot, 30 foot, if its even got a trolling motor on it it must be registered...

i know this because we borrowed a 8ft Livingtston, with a 6 horse, and got ticketed because there were no numbers/registration on the boat... where? Lake Washington... navicable waters...

fyi, the ticket was over 400 bucks, so play at your own risk...

ive always been told that if the river enters the salt water, its navicable waters, therefore boats need to be registered... the only places that arent navicable waters, are lakes that arent connected to anything, like Spanaway, Kapowsin, ect... American is navicable tho.. so its best to make sure before you go riding around in a boat...