« Reply #10 on: Wednesday 29 June 11 20:15 BST (UK) »
the only one I can see is a carpenter. I seem to remember that merchant vessels weren't enumerated until 1861 & then only if in coastal waters. My Edwards mariners from Pembs were very good at missing the census apart from one year when one of them was enumerated twice, at home & on the ship he captained in Swansea docks.
I've searched the census of vessels and can't see any obvious candidates. The only Timothy is too young & born in Oxwich. There's a Thomas born Aberayron around 1828 or so, & that's not a huge distance from Llanrhystyd.
Maybe a cert or 2 needed?

Cornwall: Allen, Bevan, Bosisto, Carnpezzack, Donithorn, Huddy, James, Retallack, Russell, Vincent, Yeoman
Cards: Thomas (Llanbadarn Fawr)
Glam: Bowler, Cram, Galloway, James, Thomas, Watkins
Lincs: Coupland, Cram
Mon: Cram, Gwyn, John, Philpot, Smart, Watkins
Pembs: Edwards (St. Dogmael's)
Yorks: Airey, Bowler, Elliott, Hare, Hewitt, Kellett, Kemp, Stephenson, Tebb