@Young:
What if the convoy Disruption phase was in the turn sequence of the nation doing the disruptions? For example:
After Germany’s non combat movement phase (let’s say they move a sub into 109 which is empty), they enter the disrupt convoys phase but instead of enemy ships rolling against them at this time, they would roll disruptions against their enemy (roll against UK for the sub they just moved). Would this be to powerful or would it make convoy zones more significant?
The difference, YG, is presumably that the willingness to risk the sub is increased.
According to my maths, on average a sub will achieve 2 ipc damage via convoy disruption. i.e. 2 rolls x ((1 x 1/6)+(2x1/6)+(3x1/6)). That assumes no ceiling to the potential disruption caused, which is incorrect, of course.
That in itself is insufficient to risk certain death.
But it will change things at the margins. When the sub has a slightly less than evens chance of survival, the 2 ipc convoy damage may warrant the risk.