DERICKSON DENE, SECRET SERVICE ACE, IN "THE NAZI SPY RING" (1939 or 1940)

Here's a rare complete story featuring Derickson Dene from "Nat Brand" (Len Fullerton).  "The Batmen," (Holy Bob Kane and Bill Finger, kids!) an evil group Dene has been pursuing have linked up with a Nazi espionage organization organisation.  No sooner is Dene on the case but The Batmen strike!  Their boss, The Vampire (who nevertheless looks a bit like TMNT's Splinter), orders his minions to fly Dene far out in the ocean and drop him!  They should have realized that Dene would make a miraculous escape and develop a machine that will locate the gang.  Still Dene must tangle with a blazing barn fire, a secret underground passage, a thrilling speedboat chase, a mysterious coded message, a deadly whirlpool, and a Nazi U-boat before he brings the case to a satisfactory end.

Enjoy.

https://comicbookplus.com/?dlid=76549&b=i