Type VII U-Boat Torpedo Questions

[AncientDresden]

Hi everyone - I have a few questions I haven't been able either to confirm or find answers for:

1. For Type VII U-boats, how long on average did it take to:
(a) load a torpedo from the dock onto the boat?
(b) reload a torpedo from the internal storage?

2. For G 7e torpedoes, I understand they needed on-board maintenance about every five days:
(a) on average, how long did it take to complete this maintenance per torpedo?
(b) did this maintenance include pre-warming?
(c) if not, on average how often did the G 7e have to be pre-warmed and how long did it take to do so?

3. For G 7a torpedoes, am I correct that they did not require regular on-board maintenance or pre-heating?

Thank you in advance!