Fish4Steel,
I would love to see a copy of your proof for using a motor on a under 16' boat. The copy needs to be current also. I really hate the looks of the numbers but their required to run a kicker on the DB.

From the washington department of Licensing website FAQ

http://www.wa.gov/dol/vehicles/vs-faq.htm#size

Question
What sizeboats with a motor are required to be registered?

All vessels with propulsion machinery are required to be titled/registered including sailboats 16 feet and over without any propulsion machinery. For information on other exemptions, please contact your local county auditor's office or closest vehicle licensing office.

Their is no yearly excise on boats under 16' so to register it for use with a motor every year is $11.50