A friend of mine is a marine archeologist, and was one of the first involved in the discovery of the U-166. It was discovered in 2001 during a sonar sweep which is required before any operations are performed which affect the bottom of the Gulf, such as the laying of a new pipeline, etc. An image showed up which appeared to be the correct size and shape for a type IX-C U-boat, except that the bow was blown off. The company doing the bottom survey brought their findings to my friend, who works for the government agency who oversees all this, and he agreed that it could be a long lost U-166. The first of many followup missions was done using an ROV, and they indeed found the submarine. According to my friend, for a single depth charge to strike a fatal blow against this type of U-boat, it had to detonate within just a few feet of the hull. He brought over some of the original ROV footage to my house. Just forward of the conning tower, the metal deck was distorted into an unmistakable crater. They speculate that Captain Claudius may have actually landed a depth charge directly on the deck, and it detonated as the sub dove through weapons activation depth. My friend said that chances are the torpedoes indeed did explode, as all of the hatches on the submarine were blown outward. The bow section broke off at the forward torpedo loading hatch.
As I mentioned, there were many followup expeditions, and not all of them underwater. A news team either from Germany or Britain tracked down the families of the deceased crew members. It turned out that the captains widow had remarried, and though she had passed away, they spoke to her surviving children. One of them brought forth a treasure trove of memorabilia she had, which included letters from her husband, commendations, etc. Incredibly, there was also some undeveloped still and movie film from 1942. They processed the film, and it turned out to be stills and footage of the newly commissioned U-166 touring around the harbor! You can see some of the still photographs here:
http://128.146.17.149/previous-programs/U166/U-166.htm
For many years, the presumed fate of the U-166 was that it was sunk in less than 200 of water by a depth charge dropped from a Coast Guard patrol plane off of Fourchon, LA, which is west of the Mississippi River. The actual aircraft which made that attack is on display in the Pensacola Naval Aviation Museum.
Link: http://128.146.17.149/previous-programs/U166/WhiteandBoggs.htm
The U-166 gave rise to an incredible number of wild stories, barroom tales, and even at least one book! As a native of New Orleans and a longtime diver, I heard MANY such tales! All of them had a similar plot: Well, I know a guy that my dad dove with who actually found the U-166, but when he went back to the spot, he couldnt locate it again! But, he REALLY found it! His camera was broken though. Stories like this ran rampant in the dive community, from Texas to Florida. I myself heard one directly from my wifes uncle, who claimed that while in the Coast Guard, they saw a spooky image on sonar of WWII German submarine, drifting along completely silent, like a ghost ship. He said that the U-166 was undoubtedly still partly full of air, and was drifting all over the Gulf! I had to bite my lip in order to suppress my laughter. Supposedly some Rambo wannabe actually published a book describing his amazing secret adventures. They included the nail-biting tale of how he alone discovered the U-166, and actually entered the submarine. He told how the bodies of the crew were still there, preserved by the diesel fuel. Of course, he could not divulge the location of the submarine, because the government will not allow him to do so.
The discovery of the actual wreck site in 2001, located east of the Mississippi in over 5000 feet of water put all of this nonsense to rest. However, it also did raise the question of what submarine was spotted and attacked by the Coast Guard airplane. I asked my archaeologist friend about that, and he had the answer, at least with as much a degree of certainty as is possible.
At the same time as the U-166 was on patrol in the Gulf, the U-171 was also. She survived her wartime cruise, but while returning to port, struck a mine off the coast of France. The boat was lost along with much of her crew, as well as the ships log. The captain survived and was court martialed. During his trial, he was asked to reproduce the log from memory, to the best of his ability. My friend is fluent in German, and actually read the transcript of his trial. One of the incidents described by the captain was being attacked off the coast of Louisiana by an airplane which dropped a single bomb as they were diving to escape. His testimony noted that no damage was done. The details, location, and time all matched very closely to the Coast Guard pilots report, so it is extremely likely that they attacked the U-171.
Be sure to take a look at http://uboat.net:8080/boats/u166.htm
I didn't see those two points on Nova. They had the speculation about the depth charge landing on the sub's deck, but didn't mention the cratering of the deck. The didn't mention the hatches being blown outward either, which would have required a powerful internal explosion. They just used the where the bow was broken off as proof that the torpedoes detonated inside. It would have been a stronger show if they had used that evidence.
Wow, great post! Second ping to the list.