We got it. Sounds like a distress signal from a small freighter between Ellesmere Island and Greenland. One Mayday, then nothing.
8 seconds sound clip from the The Atomic Submarine movie soundboard.
You can hear this line at 00:35:24 in the DVD version of the movie.
Quote context
[...]
- Yes, it's an American tactical expression.
- On July 13th, at 1600 hours, it came.
- All right. This is where Cyclops knocked off the freighter.
- This is the way he has to head for home, the Pole.
- Here we are, right in his path.
[...]