[Kip336]

I have mixed feelings regarding diving deep.
Later in the war, depth will not help much in regards to not being found with the improved ASDIC.

In 1943 (I believe, atleast, 'later' in the war) U-boat commanders where ordered to stay at periscope depth so they would be able to use the periscope to improve their, and keep their situational awareness.
That's very handy (I do that sometimes)

On the flip side, diving deeper gives you a few seconds more to dodge any incomming depth charges as they take longer to fall to the correct depth.

I end up using a mix of both, depending on how close they are, and how many there is