Hello Gretchen,
As Frances suggested, most of the Manx seem to have emigrated to Ohio via Liverpool to New York.
At your local LDS family history center, you can borrow films from the main Salt Lake City library, which cover the time perioid.
Index 1820-1846 Coz-Cul Film 350223.
For manifests of individual ships, the following film numbers cover the 1840 time period:
6 Sept 1839 to 31 Dec 1839 Film 0002285
4 Jan 1840 to 18 May 1840 Film 0002286
19 May 1840 to 13 Jul 1840 Film 0002287
14 Jul 1840 to 15 Sept 1840 Film 0002288
16 Sept 1840 to 10 May 1841 Film 0002289
My experience with indexes has been mixed--the name may or may not appear as you expect it to. Sometimes you have to be "creative" to figure out what possibilities to search for.
As far as the passenger lists themselves, you will find that very often the passenger's country of origin is given as "Great Britain" or "England" rather than "Isle of Man".
I have been compiling short genealogical sketches of the Manx immigrants to northeastern Ohio before 1850.
There were several Crow(e) individuals in Painsesville, but I didn't find a family group for William and Elizabeth as such. Any chance you are related to Ester, bp May 31, 1826 at Jurby; married Robert Brew?
Good luck with your search!
Lois Ralph