Maybe this will help? As all ready mentioned, watch the tides and don’t get caught there in a fast moving tide. Be careful and error on the safe side!
Once in a 42 foot boat, running about 20 knots I went through with close to a 3 knot tide running against me. Saw a whirlpool with about a 2½ -3 foot drop and decided since I was on plane and had plenty of room I would just skirt the outside of the whirlpool on the starboard side. That was almost a very large mistake… got on the edge of the whirlpool and the next thing I knew I was heading 90 degrees to port. Turned it back hard starboard and cleared, but it did get my attention! I’m not used to turning 25,000 pound boats like that!
Here is something I ran across, hope it helps in you’re planning: "For a change in scenery from our 1995 trip I had planned to stay close to the mainland as long as possible. Unfortunately this requires transiting Green Point Rapids. I have never gone through Green Point Rapids, and decide to look it up in Don Douglas’, exploring the South Coast of British Columbia. Don mentions a 60 – 75 foot (18 – 23M) whirlpool with a 3 foot (0.9M) drop. Hmmm. I think we will pass on that route since the rapids are currently flooding at 2.7 knots.
Instead we go up Blind Channel as we did in 1995. As we make the “left-turn” towards Blind Channel, I see Green Point Rapids on the starboard bow… The chart notes there might be some “Overfalls, Tide Rips or Races” near Shell Point (about one mile away). I am not too worried, it doesn’t sound like Blind Channel should pose too much of a problem. If it does, we can always turn around and wait for slack.
The leg past Blind Channel proves to be slow going. We average about 4.5 knots over the bottom as we buck the flood. The wind seems to be out of the SE, although it is hard to tell in these channels, as it is almost always on your nose regardless. Charles Bay looks like a decent anchorage if Blind Channel was full and you really needed somewhere to stay. It appears relatively protected and out of the currents."
Beautiful country! Enjoy your trip!