The only term that fits, and serves your intended purpose is...."motorized vessels", period, and that would outlaw all methods of propulsion short of paddling/rowing. Jet skis (PWC) are soon to enter the scene if vessel length or "horsepower" is used in the regs, so... Hmmm.
Allowing motorized vessels by authorities only in cases of "emergency" is bull$#!t. Busting kids for weed and jello shots is not an emergency, and LEO's in motorized vessels are no less destructive to the resource than sportsmen are. And it's rediculis to assume that LEO's are the only ones capable of helping in the event if an emergency.
I'd be in favor of an All or None, with no exceptions, and if they'd think about it for awhile I think most would see it that way also.