The rescue divers could hear the crew tapping out a message in Morse code: Is there any hope? After being accidentally rammed by the Coast Guard destroyer USS Paulding on December 17, 1927, the USS S-4 submarine sank to the ocean floor off Cape Cod with all forty crew aboard. Only six sailors in the forward torpedo room survived the initial accident, trapped in the compartment with the oxygen running out.
 
Author and naval historian Joseph A. Williams has delved into never-revealed archival sources to tell the compelling narrative of the S-4 disaster, the first attempt to rescue survivors stranded aboard a modern submarine. As navy deep sea divers struggled to save the imprisoned men, a winter storm raged at the surface, creating some of the worst diving conditions in American history. Circumstances were so terrible that one diver, Fred Michels, became trapped in the wreckage while trying to attach an air hose to the sunken sub—the rescuer now needed to be rescued. It was only through the bravery of a second diver, Thomas Eadie, that Michels was saved.
 
As detailed in Seventeen Fathoms Deep, lessons learned during this great tragedy moved the US Navy to improve submarine rescue technology, which resulted in later successful rescues of other downed submariners.