It's our screws. At our declination angle, running in reverse, they're pulling the Shark and cyclops right to the bottom.
9 seconds sound clip from the The Atomic Submarine movie soundboard.
You can hear this line at 00:44:00 in the DVD version of the movie.
Quote context
[...]
- We did it, boys. Dove right through the saucer's side.
- Reactor room, give me all reverse, full.
- Take a look at this depth gauge.
- 180 fathoms? We can't be sinking that fast.
- And we're at safe maximum depth already. Full stop.
[...]