Submarine Boys and the Spies by Victor G. Durham

It is a wonderful December day in Spruce Beach, FL, and everyone is waiting, waiting for something special that has been promised. The "Benson", the fast submarine built by the Pollard Submarine Boat Company, is set to arrive. But, there are more people who are interested in the "Benson" than those picnicking on the beach. Who could they be? (Ann Boulais)