I'm going to assume that Ancestry either added new data or corrected some names in the index, because I don't know how references to a passenger list with both HOLTERMANNs and LODENKAMPERs got by me before. But there it was today when I checked — out of desperation and wishful thinking — using the local library's subscription to ALE.
Although the given names don't match up at the moment, I find the reference to Bernard HOLTERMANN worth checking out. A man by that name applied for citizenship with Wilhelm HOLTERMANN on the same day in 1848 in St. Louis, and it appears that both men lived in the same general area and attended the same Catholic church. That LODENKAMPERs, possibly related to Wilhelm's first wife Dorothea LODENKAMPER, also immigrated on the same ship with Bernard HOLTERMANN makes me want to see this passenger list even more.
I haven't seen the microfilm yet because it's at another library, but this is the best lead on these families in a long, long time. These two families are among the few who have eluded me while searching immigration records and for whom I have almost no idea of their hometown in Germany.
[genealogy, Holtermann, Lodenkamper]