Pursuing some very odd thinking, and latching on to the "William Stringer Stewart" named as a son, and casting round the age he might have been, I've come up with a totally wild card that's almost certainly wrong, so few specifics to tie to, but, there's a very young William Stringer, parents Joseph Stringer and Ann Stringer, ( too young for Shannon's chap's birthdate, and not mariner,) in 1851 Yorkshire, with older siblings Elizabeth and Joseph. Obviously that's not the right chap, but it set me thinking: We've no information about young William's age/ B of B, have we, that may help us? Could a child's surname be carried over after a re-marriage as an additional or "middle" name do you think? Might that have been how William got his full name?What happened to Ann?
Does Shannon have more information on William's siblings that could help us get a handle on his wider family? Shannon says they have information from Joseph's son William, onwards....