I think there is a need for convoy zones in AA global games. They kinda introduced it in AA50. There are several ways to do it.
Have all powers include sz in their NO’s like w/Italy in AA50.
Separate sz from the NO’s and create new NO’s for the sea. That way you would have land NO’s & sea NO’s.
**NO’s have been introduced into the game, and would keep things sorta simple. I’m not sure I like that though because it would be an all or nothing deal.
Have certain sz worth 1 ipc or so (as Bardoly said) and basically let each power fight over them. Sorry still not to crazy about Germany being in what would be considered a UK zone and getting paid for it.
Assign sz to each power and if those zones are in enemy hands it cost you $ or damage markers at your capitol.(could be determined by dice but might cost to much with SBR & rockets) this makes sense because loss of ships would cost $.
Assign 3-4 sz to each power as describe by myself and others. If you keep these zones clear of enemy war ships you collect a bonus per sz (1 ipc each) or have the chance of a larger bonus if all sz’s assigned to you are clear. You could in rare cases assign the same sz to 2 powers to add some spark (for Bardoly). In this case it is assumed each power gets more income but by not keeping your convoy zones clear you lose it, results from the ships being sunk.
**As I was typing this out I noticed it might be cool to combine #4 & #5. Say on Germany’s turn it takes control of 2 sz’s assigned to the UK. Uk places 2 damage markers on its capitol. On Uk’s turn it clears those zones so now it gets a bonus to help pay for damage. On second thought I think that would defeat the whole purpose, but in AA their is a counter balance for most things lol.