This is another pirate story but it is operating on two different levels. On the surface a criminal gang is terrorizing New York City with a vicious streak of robberies and murders. It turns out that their secret getaway vehicle is a submarine they use to escape in using the cover of the Hudson River.
Piracy exists in a second variety in the story in the form of a stock scheme.
The pirate submarine fires a shell from a five-inch gun into Paine L. Winthrop’s private office. Doc identifies the explosive as trinitrotoluene. The gun crew on the submarine scores high points for marksmanship, hitting their target with the first round. They are a well trained and dangerous gang.
Gadgets: Wrist watches play an important part in the story. These devices show up again in a more sophisticate roles in The Merchants of Disaster.
Doc Savage had earlier used a wrist watch television device in Pirate of the Pacific but it was not a communicator per se. The idea of a watch as a secret communication device also appeared in The Skylark of Space by E. E. Smith which was first published in serial form in the August 1928 issue of Amazing Stories. In this story, Brookings, the general manager of the World Steel Corporation uses a watch-like device to secretly communicate with his underlings.
On January 9, 1933, American inventor and engineer Kate Gleason died from pneumonia. Kate Gleason was an extraordinary person and gifted engineer. She was the first woman ever admitted to Cornell University’s engineering program. Her family ran a machine tool company where she learned the intricacies of mechanical engineering at a young age. She was also the first woman to achieve full membership in the American Society of Mechanical Engineers. During World War I she became a bank president. Her death was mentioned in the January 23, 1933 issue of Time Magazine. Her will provided for the dispersion of her personal estate to public institutions and universities.
Lester Dent tips his hat and creates a capable female manager in the person of Lorna Zane. She is Paine L. Winthrop’s secretary but what she really does is manage his shipyard.
The Destruction of the Helldiver: Incidentally, this is the last time the Helldiver is ever named in a Doc Savage story. It seems certain that the trusty craft was destroyed by the naval mine Ull's men left in it. It is explained that this is the same type of mine used by the Coast Guard to destroy wrecks. Given the fact that the Helldiver was flooded and that water is virtually incompressible it makes it very unlikely that the submarine was worth salvaging.
Harold Davis' story, Devils of the Death has a submarine very similar to the Helldiver but it is never named as such. Rather than being a salvaged and refurbished Helldiver it seems more reasonable to assume that this is a second version of the craft that Doc built to replace the lost ship.
October 6, 1934 - Lewis J. Valentine becomes New York City Police Commissioner.
October 8, 1934 – The St. Louis Cardinals win the 1934 World Series.
October 9, 1934 – King Alexander I of Yugoslavia is assassinated while visiting Marseilles, France.
October 22, 1934 – Bank robber Pretty Boy Floyd is killed in a gun battle with law enforcement officers.
October 22, 1934 – The Union Pacific’s M-10001 locomotive sets an unbeaten speed record traveling between Los Angles, California to Grand Central Station in New York City.
October 23, 1934 – Italian pilot Francesco Agello sets a new world speed record of 440 mph in his Macchi M. C. 72 seaplane.
October 23, 1934 – Dr. Jean Piccard and his wife Dr. Jeanette Piccard rise over ten miles into the stratosphere in a balloon to study cosmic rays.
October 24, 1934 – The first Nero Wolf detective story, Fer-de-Lance by Rex Stout is published.
October 27, 1934 – The newspaper comic strip Tailspin Tommy begins.
