you really need to check your John [william['s marriage as that normally asks re father's name
The John Tear bapt German 18480611 was son of a roper living on Quay in Peel (it would be a natural career for such to go to sea) - the son of John Teare (born Peel) + douglas born Cath Carin - the family were still there (in St Peter's lane which is just off the Quay) in 1861 when John was a Scholar - I don't have 1871 census (might be on www.imuseum.im)
I know of other immigrants to US who 'added' a middle name to fit in with USA custom - if he had been baptised John William then by Manx common usage he would have been known as Willie or Bill to his friends - his younger brother was a Wm