An extinct boat of Bengal called Betnai that was seen in the Sunderbans till about 2006 occupies a pride of place at the pandal of Ultadanga Bidhan Sangha.

The boat was used to transport materials like golpata (leaves from mangrove bush) and goran wood (wood of mangrove tree) to the mainland.

A large boat of length 60 feet or so, with a wide girth, tall sterns and stems, and with a double sail in its single mast, it would navigate the choppy waters of the river.

However, with the turn of the century, the Betnai, a tidal boat, had no use as forest officials stopped the transport of mangrove trees.

Banijye Basati Lakshmi (the goddess of wealth resides in trade), the theme for the Ultadanga Bidhan Sangha puja, speaks of the entrepreneurial activities in Bengal during the time of Chand Saodagar and later.

“We wanted to have a boat as part of our pandal because the boats then were symbols of trade. Chand Saodagar had a saptadighi,” said Moloy Das, the theme-maker.

He approached social anthropologist Swarup Bhattacharya asking him what boat would be perfect for the theme.

Bhattacharya, who has been researching the indigenous boats of Bengal, said: “Officials of Ultadanga Bidhan Sangha wanted a saodagari nouka (a trade boat). I thought of the Betnai,” he said.

“It is a boat used for trading purposes,” he said.

The golpata, for instance, was used for thatching purposes. Goran wood is a very heavy and durable wood. Bhattacharya said it would be used to make beds and furniture.

The boat was thus built to size so it could carry the leaves and the wood. The high sterns and stems protected it from the high waves. The double sail on single mast would help it navigate the waters.

“The outer sail is called dunki, which is a smaller square piece of cloth than the main sail,” said Bhattacharya.

The Betnai boat at the pandal was made by boat-maker Amal Das of Basirhat. He took about 35 days to make it with the help of five craftsmen.

“I had seen betnai boats being made by my father and grandfather. I have also helped them make one,” he said. The sails were made by master craftsman Shyamsundar Debnath from Geonkhali.

Das has created a port in his pandal with a lighthouse, a ghat which has the Betnai tied to it and markets at the port to depict how maritime trade happened.