Hi Colman,
We are working on a solution for showing all tracks in the same window, in colour, with the depth colour of each trackpoint determined by the relative depth within the whole track collection. Quite a few people have requested something like this. For performance reasons we can't just show all tracks in the normal way (editable track points etc), but we should be able to create a static representation as an overlay.
One option available at the moment is to open up another window (say a contour map view of a project) and show the boat position on that as well. That way you can see your live track, and have another window (maybe at a different zoom level) showing your mapped area. Admittedly that might be difficult if you are running a small laptop display.
cheers,
Matt