Here in New Hampshire, boats like kayaks, canoes, row boats, s.u.p.'s, and sailboats under 12' not including the rudder, do not need a registration, and pay nothing to be on the water. If you add an engine, gasoline or electric, then they do need to be registered with a bow sticker.
Something like seven different states in the USA require kayak and canoes to either be registered or to have a user fee sticker.
If the State of NH needs more money for the Dept of Safety, or the Dept of Transportation for the roads, they should simply increase the existing gasoline/diesel tax and let the paddlers/rowers/ small sailors live free.
Putting a motor on a small boat also changes its status for insurance purposes ....... it becomes a motor vehicle.....just like a snowmobile or an atv.