In the five and a half years of WWII, German shipyards built 1,156 U-boats, of which 784 were lost from enemy action or other causes. In terms of human lives, 28,000 German U-boat crew of the total 40,900 men recruited into the service lost their lives.
We have always assumed that those depth charges broke the submarine's hull and their crews drowned, but this study of the Hunley crew's remains indicate otherwise.
No soft tissue to confirm their point.
I’ll look at it with an open mind but ......