Some of my rules:
1. No TC above 128 (and my crew fatigues at that TC)
2. I do not transfer external torpedoes unless the winds are at 6 m/s or less. I also only use my schnorkel in these conditions.
3. Speaking of schnorkels 1/3 speed is the fastest I travel with it extended while I'm sumberged and in "hostile" waters which is pretty much everywhere about the time they come out. I keep my Obs. scope up while the schnorkel is up.
4. Hydrophone checks every four hours.
5. When I am submerged and I have my periscope up (either one) I only travel at slow speed (3 kts)
6. In severe weather I try to stay submerged as much as possible. and I have to research this but I read that attacking in severe weather (heavy seas) was damn near impossible. I might have to make a rule up about that.
and after reading this thread I have a few more new rules.
I have a question. First, my definition of a hydrophone check is to dive to 30 meters stop for awhile, run for a short time submerged, go to periscope depth and check before you surface again. Then surface. The whole process usually takes me 1/2 hour (game time). My question is: Is that what a hydrophone check is? Because as Heibges quotes from a Uboat commanders handbook:
"Per the Uboat Commanders Handbook, regular hydrophone checks only at dawn and dusk."
What did they do for the rest of the day? Just run on the surface looking for ships?