...just in case my last post wasn't clear, the ships channel has at least 60 feet, not 6. I'm referring to the area west of Coxen's Ledge (west of Cuttyhunk).

My point is there is missing or erroneous data in the Lowrance built-in charts and the company isn't focused on making it right. That might not be easily excused in some out of the way places, but the ships "fairway" is the charted "recommended vessel route for deep draft vessels" and these (Buzzards Bay, Block Island, etc.) are not remote areas. Missing data in Lake Tashmoo also, though that is excusable IMHO.