[TEC] Torpedo loadouts (and external tubes?)

[AntEater]

Maybe this has been done to death allready, but I just found out you can vary default torpedo loadouts by time.
So for example, you can switch over the default load to Mk.18s in 1944, or make a mixed Mk.14/Mk.10 loadout in early 1942.
Now if only we had a way to limit the availability of torpedoes at base.

Second, it seems to be technically possible to add unreloadable tubes to a sub's config. This is important if somebody ever wants to make a british or dutch submarine or the Narwhal class.
However, I read that some of the porpoise class actually were fitted with two external bow tubes. Does anyone have any idea how that installation looked like?

Anyway, a lot more variation is possible.

[LZ_Baker]

You can see them in this picture:

http://www.navsource.org/archives/08/0817203.jpg

From Navsource.org

EDIT: More

http://www.navsource.org/archives/08/0817510.jpg
http://www.navsource.org/archives/08/0817512.jpg - Looks like they were added in '42
http://www.navsource.org/archives/08/0817706.jpg