But if you make abstract convoys, again the fun is flushed down the toilet. Part of the whole thing is actually steering your fleet around the ocean (like sub wolfpacks) and sinking cargo vessels. Desperately trying to find enemy cargo ships to sink, inflicting serious attrition on them in wartime. How much fun is a line over the ocean (there is no such thing anyway) where you just assign ships to either protect or attack? And how would the enemy be able to see this line anyway, it doesn't exactly run a long set of nav bouys across the seas where you just wait until an unsuspecting vessel goes by. I think supply trucks or caravans would add unnecessary micro management because on land we have roads. The ocean is a place to roam freely, now please let me do that instead of any abstraction you can't do much about.