The Submarine Boys and the Middies / The Prize Detail at Annapolis

A young crew sells their experimental submarine to the navy and is assigned to Annapolis to serve as a prize detail and instruct cadets in conning-tower, diving controls, and other onboard systems. During demonstrations and a subsequent sea cruise they face deliberate sabotage and personal peril when an antagonist incapacitates and attempts to discredit the submarine's captain. A sequence of accidents, confrontations with waterfront schemers, and a detention aboard ship force the boys to rely on seamanship and mechanical skill. Their ingenuity and persistence ultimately resolve the crises, restore reputations, and return the vessel to active service.