Mute the engine when we are in the periscope of attack and observation?

[Dagoland]

Could someone guide me, how to silence the engine noise when you are looking for the two periscopes, the noise is unreal, and it behaves like a microphone to listen to outside the sub.
If someone can guide me where to start, to try to fix that, or maybe someone already achieving.
And I have another question on a different subject.
It is possible that when the sub up to surface, making water drops through the hatch of the turret, would give a very realistic touch when the sub surfaces and open the door of the hatch and drop water into the submarine, just ask if it's worth it.

Thanks