an “up and over” ventilator, perhaps from a chain locker.
Almost certainly from the Englishman, a very long-lived three masted schooner.
Built 1857 Glasson Dock (Lancashire); sank off Musselwick Sands 2nd May 1933.
On passage from Cornwall to Ellesmere Port with china clay, she was at anchor
in St Bride’s Bay when the crew “noticed water”.
They went in the ship’s boat; the ship went under the Atlantic:
so lucky they weren’t at sea!
The metal remains of her bow (anchor windlass, hawse pipes, etc)
are uncovered from time to time.