Solution: Carry all the crew and heavy equipment as far forward as possible. Try to go under, if not possible add one bucket of water.
Result: Finally you pass the bridge with 4 millimeters tolerance. Yes, that's correct, 4 mm!!
Cumbayera's air draft measured 3,51 meters without flybridge windshield, the highest point being the rudder wheel (when having the gear coupled). By moving the "cargo" to fore you gain 3-5 cm.
Have a look at the video.
Still one has to remember that the flood in central Europe has made those waterways lower than they should be.