Didn't it win some kind of foreign film academy award?
Great flick! I own it also. When they go down to the bottom and the rivets start popping, man o man...
Germany, at the time, was the most technologically advanced country on Earth. If you wanted to know physics or chemistry or engineering, you had better been able to read and understand German.
Back when it was in theatres I was ordered to see it by Congressman Larry McDonald. I showed up at the Buckhead area (Atlanta) movie theater and there was McDonald and his teen daughter. Larry had already seen it but was back to see it again. Das Boot would certainly make my top 20 movies of all time list.