Uboot firing of torpedoes by Radar at 50 m depth

[Empty B]

I found this document:

http://www.uboatarchive.net/BDUOrder69.htm

But it doesn't make sense.
Radar didn't work while an uboot was submerged.
Any ideas?

Thanks.

[Sailor Steve]

Probably something as simple as the translator not knowing what he was talking about. It's obvious that 'sonar' is what was meant.

Or maybe the document's original author didn't know what he was talking about.

On the other hand that was American pre-war policy, and they quickly dropped it as it never worked, even once.