Although it looks form like a surfboard but the buoyancy is almost zero. It was supposed to be a simple system: you lay on the board and kick the step then a tail fin will open, impelling force will be generated, if you let the step go, the spring will return it where it is.
It had a prima-facie ladder and the rider was able to swim in water like a dolphin….but the board turned round and round, if we kick the step, the step didn't go down but our body moved forward. We reached the stage where we could almost finish up but abandoned the project because we could not bare being laughed at in local pools.