Yes, that is the family in the IGI family tree, thanks, but I don't think the father is the John Corkill we are looking for (bapt 1 July 1770 in Maughold). If someone has access to the Jurby parish register perhaps they would check the marriage on 21 Jan 1796 to see whether it records that the groom came from Maughold?
John's gt niece said in court that he went to America, and didn't enter the English navy.
Which if correct leaves two other John Corkills who did join the navy!
Sue