Between the Crow Rock and the submerged rocks extending out from the mainland, there is a navigation channel. Sailing Directions dating to 1884 note a '...4 fathom channel 2 cables wide in is narrowest part, named Crow sound. Sadde head just open of Flimston head SSE 5/8 E will lead through, but the passage should not be attempted except in smooth water and with a leading wind.'

Sources include:
Admiralty; 1884, Sailing Directions for the Bristol Channel, 4th Ed, pg70

Maritime Officer, RCAHMW, August 2014.