Ok, now I have integrated the tk2dcamera and the ships do still overlap.
Btw the documentation of the tk2camera could be a little bit more exhaustive. ;-) In the first moment I was a little bit lost, until I realized, that I have to think in pixels and not in "units" anymore.
Are there some best practices documented somewhere on how to support the different resultions?
Update: Ok, the resolutions are clearer now, I learned that i have to press play to get the view adjusted for the changed resolution. Is the tk2camera always pixel-perfect, or is there also a zoom factor somewhere? Changing the size parameter seems to not change anything.