When we arrived to the take-off there was cloud as usual where wandering around all 125 pilots. First provisional task was changed after 2 wind-dummies bomb-out and finally task was 37 km elapsed time to goal along the main road. There was no interesting on take-off and another cloud with rain coming so small group of pilots decided to fly into the cloud. They was right - because only our group reached goal. First climb wait us on quarry, then it was easy to fly 10 km under small cloud-street with very high thermals (1.5 m/s =)) ). Behind 15 km to goal all normal thermals was off, so last my climb was 0.1 - 0.2 m/s (when it was 0.4 I thought "wow!! thermal core"). So only 11 pilots on goal with.. My incredible time of 37 km was 2h07m =))). Some analysis from XCSoar - working band 670-740, average thermal - 0.4 m/s =)