Schnorkel usage - Pros and Cons

[panthercules]

I finally had one of my Kaleuns make it far enough along in the war to get a schnorkel for my new Type VIIC that I got upon my return to active duty in mid-1943 after a 6-month tour as an instructor at the U-boat school.

However, the more I've thought about it the less inclined I am to actually use the thing. As it has turned out, I've only used it once, when I was barely able to sneak away from some persistent escorts and was running out of air and batteries but was still too close to the escorts to risk surfacing since they would most likely spot my surfaced boat on radar. I figured then that if they did spot my schnorkel I would be able to tell via the hydrophones that they were approaching so the reward (continued life) was worth the risk.

However, I can't bring myself to use the schnorkel for routine operations. The way I see it, if I'm surfaced and there are aircraft or ships that wander by, I've got a pretty decent chance (at least during decent weather) of spotting them in time to take evasive action and/or dive to safety. However, if I'm cruising along on the schnorkel, with no reasonable aircraft detection capability myself, the first way I'm going to know I've been spotted by aircraft is when the bombs/DCs explode, and it'll probably be too late to do anything at that point.

If the weather is bad enough to mask the schnorkel (and its associated wake) from visible detection by aircraft (and I'm not even talking radar detection yet - I'm assuming that we Kaleuns would not consider it likely that the Allies' radar could detect something as small as a schnorkel at this point in the war anyway), I suspect it would be bad enough to make operation using the schnorkel impractical, so I'm having trouble thinking of a situation when I'd actually use this thing (other than the emergency one I already encountered as noted above).

If you cruise with both the schnorkel and the obs scope raised, would doing so give you a reasonable chance to detect enemy aircraft before they reach you and drop their bombs (would you get any "aircraft sighted" type report from your crew this way)? Do you just use the schnorkel instead of surfacing at night, when the aircraft would be less likely to spot the schnorkel/wake (and your lookouts would be less likely to spot any approaching aircraft anyway), and basically stay submerged the whole time at this point in the war?