Hans Hovelson (Haavelson)

I've been searching to find my gr.grandfather on a ship's passenger list. He left Norway in May of 1866 and arrived in New York, NY in July of 1866, according to his Petition for Naturalization. It does not have a vessel mentioned. He is listed as leaving his parish on the church records in 1866, going to America. I have not been able to find any more information as to which ship he could have been a passenger. If anyone has any suggestions for me, I'd appreciate it. Thank you.