Ok, to clarify terms, when the OP says "Register" he's using the international term for what we call "Document" and is not talking our "register" which is state registration.
Now, to the OP, I think document anywhere like Cayman Islands, Marshall Islands, etc. There are plenty of international documentation agencies that can advise you. Then you'll need cruising permits and they only require you to leave with certain frequency (US is one year). However, another issue is potential state issues and you need to look at those more carefully.
I do think there's another issue to look at first though. As a Canadian Citizen I imagine you're an ex-patriate and that is excusing you from Canadian Income Taxes. I know there's also a big difference between expat and emigrant so need to be very careful. I don't know how much time you could spend in Canada before being taxed as a resident, since you're a citizen. So you need to look at any impact living on your boat in Canada might have on you from an income tax perspective.