When you're in quicksand up to your knees and crocs are heading your way, you might want to have your chaps operate your famous pnuematic cannon, or what's the frickin' point of being an inventor, anyway?

For once the ship wasn't ruined in the course of its use; Frank just ran it into a rock.

But note: for once, he takes a cut of the proceeds. I'm guessing his War Department contract had run out, and he needed something to pay the help and stave off Unionism.