Important evidence in an English murder trial was lost at sea, so naturally they turn to that Yankee Genius, Frank. Could he rescue the stuff? "Sorry," he said. "This is an airship issue. Your timing couldn't be worse."

Well, no. He had a new sub ready to go. A little insight on Frank here:

The papers are rescued, and the condemned man is saved with minutes to spare. As for the richly appointed Venture:

I'm starting to think maybe the government doesn't want any of his ships or secrets. They wouldn't last half an hour in an actual war.