Washington state boat use permit

[C-Wolfe]

I purchased a boat that is located in Washington state (bellingham) and plan on using it there for a few days before shipping it home to Alaska. I would have the boat and trailer register in Alaska prior to this. I signed a tax waiver that specified clearly that I need to have the boat out of state before 45 days, I can return and have 60 days before i need to filled for an extension or register to boat locally. I will be there during the very end of the 45 days and I'm thinking of taking the boat to Canada (Sidney BC is about 50 miles away). Anyone know how long I need to be outside of Washington state for the reset to happen? Second question, do I need to file for a use permit for the first 60 days of use?
I have been thru a lot of the Washington state literature and those item are not very clear to me. I will appreciate any answer or to know who I can talk to to get a clearer answer.
Thanks