The buoyancy force for objects (or at least fuel tanks) in water is too weak.
The buoyant force for this two-cube construction corresponds to the craft being submerged in a liquid with a density of +/- 250 kg/m3.
This is with water physics set to high.
Hello! I really want to see the updated avionics set, we don’t have a course direction for planes, only you can do it :) I really need your help)