This comic spun off from a kids' radio serial, "The Sea Hound," which ran from 1942 to 1951. At first it was produced in cooperation with a government agency set up to counter Axis propaganda in Latin America. From Wikipedia:
"Between 1942 and 1944 the series was produced with Nelson A. Rockefeller's Office of the Coordinator of Inter-American Affairs and was part of a national program to strengthen inter-American relations. Broadcast five times a week, the show featured Captain Silver and his sidekick Jerry hunting Nazi spies throughout the hemisphere. Every episode took place in a different Latin American country."
Columbia produced a "Sea Hound" serial in 1947 starring Buster Crabbe. We have some of the radio episodes in our Old Time Radio section under the title "The Adventures of the Sea Hound."
Link to the book:
Captain Silver's Log of the Sea Hound 4