A pair of historical questions..

[Aviv]

I have a pair of historical questions I thought of in the last week, so I thought you old sea-dogs could give me some information and feed my curiosity.

First, in my reading I read that a lot of submarines (especially uboats) were sunk by aircrafts. Why didn't they just dive straight when they detected the airplane on radar? For example in the game, I can detect and dive to 30 meters before he can even close to me and is over the horizon. Why did air attack cause such a problem to submarine crews? How frequent were the air patrols?

Second, I was reading the other day (bored recently) about how crews can escape from submarines. I learnt that those two small hatches at the back of the submarine (with one at almost 45 degrees) is part of the system which allows sailors to escape; the "escape trunk" (more information on Wikipedia). I wanted to know how successfull was that to allow people to escape and survive sunked submarines?

I guess that's all!
Thanks!