regarding the pipe freezing freezing the amount of volume the pipe can hold will effect this as the vent pushes into the pipe it increases the pressure to the point where you can get freezing damage one way round this is to increase the pipe volume to give the passive vent/cowl chance to vent out you might want to try a pipe tank as even the small one will add 100ltr to the pipe volume
Chief, now you can make ur sub a “real “ underwater sub. For the pipe creaking, you can connect an active vent directly to a passive too
regarding the pipe freezing freezing the amount of volume the pipe can hold will effect this as the vent pushes into the pipe it increases the pressure to the point where you can get freezing damage one way round this is to increase the pipe volume to give the passive vent/cowl chance to vent out you might want to try a pipe tank as even the small one will add 100ltr to the pipe volume
Ahh I will give that a try.