Larry Corkill was looking for the same Thomas Corkill through the BB in 2007, although he thought he was looking for the Lonan one b.1813 (mentioned recently on this BB under "Corkills from Maughold"). Len F wrote there that "IGI records only one Thomas Corkill from Lonan around 1813 and he appears to be still there in 1851 unmarried". So my vague memory of him going to the USA was probably from this interchange, and wrong.
Lois found the old thread with Larry Corkill and Greg Corkill postings at:
www.isle-of-man.com/genealogy/messageboard/manx_archive_2.pl?pro=search;pmd=sread;srchid=91377K7uEvCCDmg6HgP1299952975;spage=1;sanc=513721;sbid=12;md=read;id=513706
Sue