A FANTASTIC story, as dramatic and compelling as any high altitude mountaineering epic.
I had no idea deep wreck diving was so thrilling.
Hitler’s Lost Sub was a NOVA TV special first aired in 2000:
In 1991, professional diver John Chatterton discovered a sunken German U-boat from World War II, lying undetected only 60 miles off the New Jersey shore, its unexploded torpedoes and the bodies of its crew still aboard. This two-hour special follows Chatterton and his dive partners in their dangerous quest to identify the missing U-boat, a pursuit that takes six years and costs three lives. The U-boat’s history involves unusual coincidences and a startling twist of fate. …
Of course Hitler lost hundreds and hundreds of submarines, but this one has a particularly compelling story.
Highly recommended too is this book on the adventure:
Actually, there is a follow-up book contesting the book I read: Shadow Divers Exposed: the Real Saga of the U-869 by Gary Gentile. I will not read that one. Sounds to me it is dull, badly written and perhaps a work motivated by jealousy.

I LOVED Shadow Divers. Amazing story. Crazy people.
I am happily surprised you have read that one. I thought it was little known.
Heard the recommendation on TWIT, I believe it was.