Anybody have any idea what the heck this is? It is a hard point under the fabric. I have not noticed it on any other 7 or 8 series aircraft. Based on location I am guessing it is related to the fuel lines or sump. On my aircraft, it protrudes beyond the surface plane of the fabric and creates a stress point. The avgas from the vent above it has trashed the dope, and the fabric stress and UV are damaging the fabric. Gonna have to be repaired soon; might get away with stripping and re-doping, but I suspect I'll need to cut out that area and patch with heavy duty fabric and anti-chafing tape. Is there any way I can fix the protruberance?