OK, refreshed by a cup of tea . . . Samuel Culpin, christened 5 Sep 1827 in Spalding, Lincs, son of Richard & Maria.
He appears in 1861 as the Master of the vessel "Hope", presumably a fishing boat, out of Hull (I think). By 1871, he's the landlord of the Punch Bowl Inn, New Road, Spalding; married to Ann and with four children at home.
He caught my eye, as it were, because his daughter's full name is Maria Mary Gostelow Culpin and when I first "saw" her online, I was tracing a related line of Fordhams in Huntingdonshire and one of those married a Susannah Gostelow. With such an unusual name, my ears pricked up at once.
So, back to Samuel - his parents turn out to be Richard (Culpin, obviously) and Maria Gostelow, who were married on 24 Sep 1810 in Spalding. They had seven other children, of whom more later, and I estimate that Richard would have been born circa 1790.
Problem is that I have a number of potential candidates for this chap . . . I guess I just need to eliminate them one by one and apply the Sherlock Holmes theory that "whatever remains, however unlikely, has to be the truth" (with apologies to Sir Arthur Conan Doyle for mangling his quote).
Onwards . . . . .