Doc Savage The Man of Bronze (1972 series) #4

The Silver Death’s-Heads set a trap for Doc Savage outside the Indian Head Club, but Doc turns the tables on them and, with Rapid Pace and Hugh McCoy, explores the club. They rescue the aides, fight off another attack, and discover a map of New York Harbor in a hidden room. Doc and company head up the river in his submarine Helldiver. On the way, Doc reveals his suspicions of Bedford Burgess Gardner, a shipping magnate who built his business by shady means, and his belief that the secret project at the Commodore’s boat yard was a submarine for the use of the Silver Death’s-Heads. His suspicions are confirmed when the Helldiver is attacked by the enemy sub and a furious underwater battle ensues, with Doc and his men the victors. Doc pursues some escaping crooks to a hidden refuge, where Ull is being berated by his mysterious leader for attracting the attention of Doc Savage with his crime spree. Doc enters and overpowers the villains and unmasks the leader as Bedford Burgess Gardner, but under a further disguise he is really Hugh McCoy, who created the phony Gardner persona to deflect suspicion.