While the effects men prepared the explosives for the movie attack, Fleischer rehearsed the sailor a dozen times saying ‘Boom’ for the explosion cue. The sailor was perfect every time. But would the splash land on him?

This would be a one time chance because setting underwater exlosives took an hour. Also many other scenes had to be shot that day. So the splash had to be perfect on the first take.

Finally, Fleischer rolled film and yelled action. Planes flew over, the explosions went off and the water splashed on the sailor perfectly. Fleischer waited for the line, but the sailor didn’t say a word. Finally, Fleischer had to cut.

“Why didn’t you say the line?”

“You didn’t say Boom.”