I suggest posting what else you know about him such as his birth and death dates even if only approximate. Other things such as where he lived and who he married might help.
The indexes of immigration are loaded with mistakes partly because the original writing is often hard to read and partly because some indexers are lousy at their job. Try as I might I could find any Clement (or something similar) who arrived in the U.S. in May or June 1816. Of course the year could be wrong.