OK. I see what you are talking about now.
Try changing the collision mesh with the one the city GR2 has.
I'd do it but I'm not home and don't have all the needed programs with me.
If that solves the issue create a new collision mesh with a broad base but deep enough to not hit a sub or ship in the area.
I'm looking out the window of my temporary apartment in Cleveland, Ohio right now.
All that view needs is a VIIA in the river. LOL