Convoy Interdiction Query

[mcaryf1]

This is a somewhat long post about what I am trying to achieve and it ends with two questions about how the game engine will treat the convoys I am describing.

I have been experimenting with a Pacific Convoy route to represent the US Lend Lease Aid that went that way to USSR. In fact a very significant proportion went by that route and was unmolested by Japan whom I guess did not want to get into trouble with USSR by that stage of the war.

For those of you who have not looked at how convoys work this seems to be the way of it. Each minor country can send a convoy to its major partner and each major country can send just one convoy to any of its major Allies. There can only be one convoy route active from each country (major or minor) at any specific moment. The scenario designer can specify several alternative routes in case, for example, the first route's destination port has fallen into enemy hands. The game selects each convoy route in the sequence they appear in the convoy script and only looks for the next one from a country if the initial route is unavailable.

In the standard scenarios there is the possibility of the US using a Pacific route to send Lend Lease to the USSR but it would require the US to UK route to be out of action (e.g. UK Government in Canada or Australia) and a potential US to Arctic Russia convoy also to fail. I have not seen it actually occur but that is what the convoy script specifies.

In fact the Pacific route saw the greatest traffic for US goods to USSR but as the US can only have one outbound convoy it obviously has to go first to the UK so it is the UK that effectively passes some of this aid on via its convoy routes to USSR.

In order to create a convoy route between the US and USSR via the Pacific I decided that I would make one for the (mostly) empty ships on their return journey from USSR to USA. This seems to operate satisfactorily. I set up a Decision Event for the Allied player to agree to set up a regular payment to the USSR from the USA and part of that effectively comes back again in the USSR to US convoy. There is a risk to the Allied player as two interlocking DE events effectively take a charge from the US and credits it to the USSR for the rest of the game regardless of whether the USSR has actually survived. To make it a bit of a gamble I charge the US in its DE forty MPP per turn but I credit the USSR with sixty MPP of which it sends about twenty back again. Thus if things work out it costs the US 20 MPP but the USSR gets 40. Of course there is always the risk of the convoy being interdicted so there might be losses and in the worst case the US loses 40 MPP for every turn for nothing if the SU is defeated.

I am finally getting to the question I would like to be resolved - if Japan is at war with USA but not USSR how will convoy interdiction be handled for a USSR convoy to USA? Clearly German submarines ought to attack it but will Japanese ones?

Finally a general question about convoys - does the game engine automatically direct AI raiders to convoy routes or is that something that the AI naval scripts have to take care of?

[Bill101]

Hi Mike

If Japan is not at war with the USSR it could still interdict the convoy routes, just as German U-Boats can interdict US ones to the UK before the USA enters the war.

In answer to your second question, naval scripts will be needed to direct attacks against them. That won't necessarily stop all AI naval activity against them though, but it will probably prevent any large scale offensive against them.

So the lack of such scripts could reflect reality, where Japanese submarine doctrine didn't really envision them for use against merchantmen.

Bill

[mcaryf1]

Thanks Bill

Mike