The show is about an expedition looking for one of the American privateer ships sunk off the Welsh coast during the Revolutionary War. Much of the show is a history lesson where they explain Ben Franklin's role in this rag-tag navy--along with historical re-enactors pretending to be these characters. The rest is the expedition looking for one particular wreck--showing their work and the artifacts they recover.
Because I am a scuba diver, I had a greater appreciation for this National Geographic show. It's because the diving conditions that this team are up against are TOUGH. The water is REALLY cold on the Welsh coast (even in summer) and the men are forced to use dry suits. But what really made this a bit crazy was that the shipwreck was up against a sea wall--and the current is, at times, smashing them up against the rocks. And, to top it off, the visibility isn't particularly good. It sure makes me feel blessed to be living here in Florida--and other divers will likely marvel at the conditions under which these folks worked.
While I enjoyed this show, one serious weakness is that there are a lot of COULDS and MIGHTS. In other words, much of the data doesn't conclusively prove anything...just that it COULD be one of Franklin's ships. And, despite the show talking about 'compelling evidence', it isn't. Because of this, the show might have been better to focus more on the historical background than the shipwreck itself. Mildly interesting but not exactly convincing in its conclusions.