Thank you @sagar.
I spoke with the boat operator when he was enjoying the sunrise.
Actually the boating should start at around 10.00AM, but we somehow managed to start a bit early. He also gave us ticket for the ride which is 650 rupees for two, charged by PTDC. Explored Yanam well but could not go deep as its a sudden plan. Yanam has really a very good potential to expand. But I think its better left untouched preserving its natural beauty. There are many unexplored places, small and beautiful islands, thick mangoves around the place. Will explore all those and write a detailed trip report soon.