Submarines

[Fallschirmjager]

How are these represented?
Are they units or abstract points?
Can they attack both warships and shipping?
How are they combated against?

[SMK-at-work]

They're treated the same as other ships, except they can only be attacked by destroyer flotilla's.
 
Basically you put them on "anti-shipping" or "patrol" in an area, and sit back and see what happens.  "Anti-shipping" gives them a higher chance of hitting transports, "patrol" spreads teh chance more evenly if there's any warships in the area.
 
the only defence against them is to put destroyer flotillas into an area where you expect subs to operate and hoope they can hit it/them.

[Fallschirmjager]

Excellent

[flintlock]

For any interested, here's what that may look like:

Here I've selected the 1st (UB). You can read associated stats on the right:



Next, I'm going to assign the 1st (UB), docked at Wilhelmshaven, to patrol in the North Atlantic on an anti-shipping patrol:



Here's a result of one of those patrols:



It's abstract but seems to work quite well.

[Fallschirmjager]

One thing I think needs to be adressed is the issue of accidents

More U-Boats were lost to accidents than to enemy action
Also the British should be given the option of using some of their resources to lay minefields

Mines were the #2 cause of U-Boat losses

[SMK-at-work]

Mines and accidents are miles below the level of GoA's scale - heck IIRC somethign like 75% of aircraft losses were to accident too.....but again it's not important at this scale IMO.