When you say shoal draft, what is that? How much does a shoal draft boat draw?
I cruise in the PNW and there are a few places where you can put a really deep boat in the sand but not many. Specifically, the Comox Bar, around the islands in the north end of Georgia Strait and at the mouth of the Fraser. Anything that draws less than ten feet is pretty much a free runner here. I had a boat with a 10 foot draft and I sometimes had to wait for the right tide in Comox or Port Townsend. Most of the places there was lots of water. I currently sail in a 5' draft boat and often
anchor with one end of the boat tied to shore (as most folks around here do).
Fog, yes there is lots of fog in August and September off the west coast of the island and to the north. Check the pilot
charts. The inside is fog free most of the time, particularly summer but it is also wind free. Warm air over cold water equals fog everywhere off the west coast. They call it fogust here.