tonight on discovery canada

[Sailor Steve]

Originally Posted by Capt. Shark Bait

i'm thinkin that could be a translation thing, but yeah, "blow ballast" would result in submerging. in U571 the order givin was the same or blow all ballast, or something similar

I don't know about WW1 Germans, but in WW2 and later "blow ballast" is the order given to empty the tanks, forcing the boat to surface.

In U-571 Harvey Keitel also gave three blasts on the klaxon and said "Dive, dive!" Three blasts is to surface, two is to dive. I wouldn't use that movie as an example of anything, except maybe how to make a bad movie.