At this point, the speed increases from 4 to 9 knots.
5 seconds sound clip from the All Through the Night (1942) movie soundboard.
You can hear this line at 01:30:55.898 in the Blu-ray version of the movie.
Quote context
[...]
- And we can only accomplish this by an action as daring and as bold as the one planned for tonight.
- What vessel is he talking about?
- Quiet.
- At this point, the speed increases from 4 to 9 knots.
- And according to our plan, the vessel will reach the minefield at approximately 5:15.
- So the vessel will reach the minefield at 5:21 exactly.
[...]