Hello All! This is a question from Marlboro's OWTW2 contest. I am
going absolutely nuts over this question. I have read other answers,
but I am still not happy with the answers. The question reads: For
most, going west meant traveling by both wagon and boat. But who was
the guy who figured out how to do both at once?

The possible "inventors" could be James Logan, John Mohler Studebaker
and Wind-Wagon Thomas. However, I think this answer may not be so
obvious. I have a feeling the answer will have something to do with a
process involved in water sealing or water tightening the wagon. I
have searched the web high and low. Can anyone help?

I reckon that this refers to the 'Prairie Schooner' ... 

This was a wagon with the 'schooner' part implying a boat.

What else?

But who was the inventor?

The obvious answer would be the prairie schooner; and I believe that
Studebaker was the inventor--however, the answer doesn't seem to have
any correlation with the clue. According to Marlboro, the text of the
clues have hints in them.

Now, I did find reference to an African-American inventor named James
W. West who made some kind of modification to the wagon, but that was
in 1870--long after the Gold Rush. Then, I also thought that the steam
wagon would be a possibility. I still do, but that's how I feel about
all of the possibilities at this point. I can't seem to narrow
anything down. And in the back of my mind I keep thinking that there
must be some kind of clue in the question and I'm overlooking it.