Don Winslow of the Coast Guard: Chapter 2- Battling a U-Boat

From the land of public domain comics and public domain World War Two live action serials, comes Commander Don Winslow (the original Commander Marvel), who, along with his friend and junior officer, Lieutenant "Red" Pennington, after his initial adventures with the Navy, are assigned to the Coast Guard. There they are ordered to devote their activities to anti-fifth column work on the mainland. Commander Winslow learns that The Scorpion, a fascist sympathizer, is in the pay of the Japanese and is expected to lay the ground work for a Japanese attack on the Pacific coast. Constantly in peril and aided by Mercedes Colby, the daughter of a Navy Admiral, they investigate secret island-bases and battles with submarines and enemy planes…

Learn more about the original Commander Marvel, Don Winslow at: https://en.wikipedia.org/wiki/Don_Winslow_of_the_Navy_(comic_strip)
Learn more about this film serial at: https://en.wikipedia.org/wiki/Don_Winslow_of_the_Navy
Learn more about the Commander's second film serial, Don Winslow of the Coast Guard, at: https://en.wikipedia.org/wiki/Don_Winslow_of_the_Coast_Guard