Olives stink like sulfer

Help! Maybe somebody here knows:
I have previously successfully cured olives in the old traditional sea water method (living on a boat makes this technique very attractive), however today i came to drain and refresh them and a very strong sulfer smell comes of one of my jars... no other sighns of spoil.. (mold, slime, etc...)
What happened? Are they spoiled? What did i do wrong? Can i rescue them?

There must have been sulfur bacteria in your water producing hydrogen sulfide gas you are smelling. If that's the case, heating your water to 160 deg F will kill the bacteria. If its just one of the jars and not all of them, I would suspect some other type of bacteria that may be more harmful.