We visited Spanish in 2012. The channel was very shallow. The depthsounder showed only 1.5-feet of water
below the keel
of our shallow draft
22-foot power boat--the sounder is about 1.5-feet below water line, so maybe 3-feet of water in that channel.
We also transited the shallow channel at the end of Collins Inlet into Beaverstone Bay. There was barely 3-feet under our keel
there, i.e. about 4.5-feet indicated on sounder.
Both would be a challenge in a deep draft
sailboat. Besides, Spanish is not much of a destination