boat does not have to be registered unless,
1- It is over 16', and
2-Has a motor larger than 10hp, and
3-Is used on "Federally Regulated" waters...
so as long as it is under 16', has a 9.9hp motor or smaller, and doesn't go on "federally regulated" waters, (like the sound, I presume), then you don't need to register it...i gotta register my trailer, but I don't register my boat...it's used just on the small lakes around here.
Not just the sound. Federal waters or "navigatable waters" will require licensing...The columbia for instance, is considered federal waters...so is lake washington IIRC. Odds are if it connects to the salt, or has a damn or locks, it's considered Federal.
There is a list of "Federal waters" for washington state somewhere out the internet...google-fu!
