Dear Mr Clayton,
I have been working through the Crinall genealogy for some time, and keep crossing references to the Crennell name from the Isle of Man. I have yet to make a firm connection, but believe there may be a link at your Grandfathers (or earlier) stage.
I myself have found a John Crinall (c1780 - 1850) living in Northumberland who had 9 children. Two of the sons were sailors, one sailing from Liverpool on the America's run, and the other out of London to South Africa and Australia.
The Liverpool / Isle of man proximity is interesting given our unusual surname.
If you have any earlier information re grandparents on the Crennell side we may be able to prove / disprove a link once and for all.
Regards,

David A Crinall