How did Ben Cartwright go from being a sea captain to owning a ranch?

In the episode, "Elizabeth, My Love," Ben is a sailor and the Captain of the ship he is working on is Elizabeth's father, Captain Stoddard.

The Captain is being forced to retire and the board wants Ben to take the Captain's place, but Ben has a dream of going west. He asks the Captain to go into business with him so that the Captain will have something to do, and Ben can earn money to go out west with Elizabeth.

If there is another episode in the series that claims that Ben was a Captain of a ship, I haven't seen it.