An update on US boaters transiting through BC to SE AK:
My cruising buddy, who lives in Sidney BC, just spoke with a CBSA person in Victoria. She said the rules for transiting through BC to SE AK are very much as Canada's website describes under
Transit through Canadian waters, though they could change of course. It seems likely we may have to show a recent negative COVID test, for example. Here's the web site:
https://travel.gc.ca/travel-covid/travel-restrictions/border#waters
Some additional items CBSA mentioned on the phone:
If you plan to transit to through BC waters to SE AK, make a written plan for your trip, including where you plan to anchor each night, where you will stop for fuel, and how you will stay isolated while in BC. CBSA assumes a six-knot boat to estimate how many days it would take, so there's no need to be in a great hurry.
Bring enough food/supplies (things that are allowed into BC - no potatoes, only so much alcohol....) to make it though BC to Ketchikan. Or, make arrangements with one of your fuel stops like Port McNeill to go shopping for you and deliver supplies to you at the fuel dock. You may not stay at a marina, or go shopping yourself. Don't stop at any small native communities like Klemtu or Hartley Bay.
Check into Canada in person at a CBSA office (Sidney, Victoria, Nanaimo, for examples) and provide them your written plan. After checking in, you do not need to call in to stop for fuel or to anchor.
Anchoring each night, follow your plan, as weather etc permits, until you cross into SE AK. Then call CBSA to check out of BC.
I think I have covered it fairly well, but I may have forgotten or mis-stated something. You certainly will have to check the rules for yourself.