We're on a 2002 Bav 40.Troubleshooting an engine issue and wondering about how the diesel tank vents. Anyone else out there with the same system? It seems to have two hoses that go to the same hole. One is the diesel fill hose and the other is a thinner vent hose. Both go to the diesel fill opening on the transom that have a metal, screw-on cap with a little chain holding it on. It seems that the diesel tank can only vent then when the cap is off and you are filling the tank? It is a very strange set up compared to most boats, and even other Bavarias we have seen have a separate hole outside for the diesel tank vent.