If you put the player boat tails back in, all ships will have tails.
It's a single TGA and it affects all ships/planes. We have already said we will make a mod to return the tails but we're too busy enjoying our work.
I can understand people having trouble with close up navigation, maybe leaving port for example, however, I use waypoints to leave port or I manually navigate from the bridge. Shouldn't be too hard to do.
As for close navigation at sea or in a convoy, at a higher level of zoom, the U-Boat and the ships within visual range will be displayed on the map with their direction of travel indicated.