An extensive area of shoals of varying depths from 3.6-12.6m is shown on an historic Admiralty chart and includes the Three fathom and Two Fathom patches. Contemporary Sailing Directions note 'Kenfig and North Kenfig patches? are mostly rock, with depth of 3 to 4 fathoms over them. North Kenfig has but 10 feet water on it, and is about 2 1/4 miles from Hugo black buoy; its lies about a mile WNE from the entrance point from Hugo Black buoy and upon the same bearing 3 1/4 miles distant, are gravel patches of 4 fathoms. The space between the shore and the shoals ? is studded with rocks, the least water over them being 2 fathoms, excepting off Rhwchian farm, where at least 4 cables distance form the shore, there is a little as 6 feet.'

Sources include:
Admiralty; 1884, Sailing Directions for the Bristol Channel, 4th Ed, pg115
Historic Admiralty Chart 1161-C1, RCAHMW Digital Collections sourced from UK Hydrographic Office and published in 1885

Maritime Officer, RCAHMW, September 2014.