New Tom Hanks movie "Greyhound"

[Jenson71]

Originally Posted by Frazod

The subs of that era could only operate submerged for limited amounts of time. While completely underwater, they ran on battery power, as the diesel engines required air to function. They would run out of both breathable air and power if they stayed under for too long.

A History channel website says they could be under water for about 2 hours. That blows my mind. I honestly thought they were roaming around for about as long as their food/ammunition supplies could last.