Red hatched areas off of North American coast?

[Nethog]

I have a german ship on one of the red hatched areas off of the north American coast. During the turn I see a message that production was disrupted for a mine and a city. What is the specific effect on the enemy?

[Ktonos]

The mines close to the port get hit for some damage. So next turn his production is reduced for this amount. Now this isn't something dramatic but if you continue unopposed for several turns mines and ports will drop to 0 humbering his production for many mpps, plus even when left alone each resource can only recover 1 pt per turn.

[BillRunacre]

It will reduce the strength and therefore supply and income value of some enemy resources.

[Nethog]

Hmmn I see. Thanks. So is it better to raid the red zones or the actual convoy route?

[Ktonos]

I always prefer the convoy routes. The mining sites need continuous sub presence for long periods to make a difference, and they are visible and static during this period opening them to an allied massed destroyer attack. I've seen this used successfully only twice, both times against me, once as a misdirection for Sea Lion where I send said massed destroyer group to Canada and wasn't able to defend subs in the Channel, and the second time as a preliminary operation from Fafnir before his invasion of the Americas.