[Gildor]

Look at the multiplayer game as a "campaign". It is set on a world map. That everyone views. Sort of like an intellegence map. it is broken into the sectors, e.g. BE3922.
layers.

Now, the players have a set amount of time to plot strategy. Most of the time it will be a movement. A player is given a "boat", a base, flotilla, etc. In base, you get a set amount of fuel as "expenditure points". You use this to get to your assigned sector. Before you leave port you view an overhead map and you plot your course to your sector ( or wherever you wish to go) and this plot uses your fuel EPs.

Once the time period is done. (say 2 min a day) the game calculates the movement of convoys, individual ships, player ships, aircraft, etc. If any "conflicts" are calculated, that player is dropped to 1X combat to deal with the situation. If there are other players within a set distance, they can join in at that distance, (say 50 kms).

The rest of the game continues on with the "campaign" stratagy screen. Once the player finishes his combat, he joins back to the campaign screen(CS).

If a player is in combat it shows up as report on the CS. Players could plot a course to intercept and join the multiplayer "hotspot", simulating wolfpacks.

If a player wants to crusie around in a sector he can set his sub to "patrol" and drop into the game. Other players would see an icon that the sub is on patrol and could join if they wanted and are given permision to join that player. The beauty of this is its by invitation, and you can set up for a wolf pack ambush if a convoy shows up.

There is no actual date in the game. It is just a map, with possible convoy/shipping routes. Players just use the campaign screen to move, see the status of sectors(who is patrolling in it).

There could even be a "BDU" moderator that issues orders.

With a server setup, and custom software, you could probably even use SH3 or SH4 to allow the campaign screen to drop players into the game (or multiplayer) if applicable. The CS software dropping the applicable game status info right into the "client" setup.

Basicly, the Campain software would be an interactive multiplayer lobby that uses a server-side databse of convoy routes to update a screen.

Anyway, Im not a software engineer, and I probably didn't explain what I envision very well, but I think it is do-able.