Book #4 in the Tom Swift 100th Anniversary Project. Tom Swift's father, Barton Swift, is a great inventor with many patents and project sold to both private enterprises and the Government. Now, Tom joins him as they set out to test a new deep diving submarine Barton has build to try to secure a military contract. Driven by a radically new form of propulsion, it is up against other submarines, but their primary opponent is an unscrupulous man who will do everything possible-including attacking the Swifts-to win that contract. Things take a turn when a gold-laden ship sinks off the coast of South America, and it becomes a race both in distance and diving ability to see which submarine will win the contract and also get that gold! ------------------------------------ This book has been substantially rewritten to remove outright racism and to enhance the mechanical and technical interests. Many books of this era used sentence structures, certain words and even punctuation in ways that can be confusing to younger readers today. So, every effort has been made to alleviate this issue while retaining the flavor of a story first told more than a century before.