Are you sure you have the right Thomas Radcliff ?
Ancestry.com world connect does show a Thomas Radcliff 1818 married in USA to Elizabeth Gawne and records his arrival 1827 on the barque Ocean. The Gawnes arrived 1826 on Aurelia.
The burial records of Ballaugh indicate that this Radcliff family never left the Island.
See also Brian Lawsons wills Anne 1852, Thomas 1845, Thomas 1891- this Thomas used Craine for his son,s second name.
There was another Radcliff family on the barque Ocean see Frances Coakley,s site on emigration.
The records on world connect are made by Daphne Gawne who I know to be precise so check my comments.

Len Faragher