Any hope for shallow water victim?

[johnno74]

Originally Posted by jimbuna

Sitting on the bottom does not afford you any advantage
Once/if detected your best chance is staying on the move

This is realistic. Active sonar (known as ASDIC in WW2) works because sound waves tend to be reflected when they hit something with a different density - the larger the density change, the stronger the reflection.

So yes, the sonar reflects off the seafloor - but the density change going between the sea and the seafloor is much smaller than the density change between your u-boats pressure hull and the air inside it.

This means your u-boat acts amost like a mirror for active sonar - while the return from the seafloor isn't nearly as strong.

Sitting on the bottom will reduce the noise produced by your sub as there are no motors, propellors or pumps running, making you almost impossible to pick up on passive sonar (hydrophones), but makes no difference at all to active sonar.