Submarine S-49 had three different lives. One of the last submarines built by the Simon Lake company, it served as a United States Navy ship for five years, testing innovative devices, and was the first Navy vessel fitted with true piezoelectric SONAR. Consigned to the scrapyard in 1931 by the London Naval Treaty, it was rescued from destruction by two politicians from Revere, Massachusetts. It was the first Navy ship to be privately owned. They towed it back to Massachusetts, fixed it up, and exhibited it to the public. Two years later they towed it up the St. Lawrence River to Chicago, where it was exhibited at the Chicago World's Fair. After showing it around the Great Lakes, they re-engined the submarine and took it out into the Atlantic, taking it to cities along the eastern coast until WWII broke out.

They tried to give it back to the Navy as a training vessel, but it had been too heavily altered, and it was once more consigned to the scrapyard. But, once again at the last minute, Navy Research rescued it, had it fitted up so that it could dive again, and used it in SONAR fuze testing, until one day it would no longer rise to the surface. It sits at the bottom of the Patuxent River in Maryland to this day. This work tells about the exploits of the S-49 and those who commanded her, telling of the advances she made, about the battery explosion on board, how she avoided being junked, how she was marketed, and how her civilian owners finagled her out of the destruction mandated by the London treaty.