A Navigator on the Map to give navigation a more realistic feel, and help with open sea patrolling and getting patrol groups, convoys etc together.
Navigation buttons on the map for...
Position: a mark showing my position on the map with Caribbean time (max 5 on map; 1 minute timer between each to stop spamming)
Clear: clears all Position markers
and...
Protractor: shows distance in km next to the heading. The course line from the protractor could have 10km marks on it or similar.
Sextants, compasses and ship's logs were standard kit so it isn't ahistorical. I was rather put off when I started playing to find a sailing game with apparently no concept of distance.
I think this would improve look and feel and get me away from the coasts more often. Don't see it would be too difficult as no new data or complex calculation is needed - there are already NA maps on the interwebs that do all this from F11, and the Trader Tool already calculates distances at sea to the ports. I have already posted this under Suggestions, but a few other people were discussing it in-game so why not try again...