Currents and depth charts a possibility?

[Sailor Steve]

Originally Posted by Hartmann

I think that in WWII technology don´t was enough accurate to allow the use of charts and underwater terrain to hide from scorts , only a rough estimation of depth

Exactly true. They hid from active sonar by sitting on the bottom, where the sand (not the rocks) absorbed both the beams and the depth charge blasts, making it somewhat safer. It wasn't perfect - we don't know how many tried and failed, because they aren't here to tell us.

It was impossible with the technology of the day to "see" anything underwater, so the sub couldn't know where rocks or ships were that they could hide behind, and they ran just as much risk of hitting those objects as they did using them for cover.