The exact location of the sunken launch has not yet been identified since the time it capsized with over 150 passengers in Padma River near Mawa ghat in Munshiganj on Monday morning.
With the help of side-scan sonar, the rescuers are striving to find out the spot where the launch sank, BIWTC Director Md Hossain said.
Till filing of this report at 12am Tuesday, the rescuers couldn't identify the place underwater where the launch was.
Rescue operation is being hampered due to strong currents and gigantic waves in the river, Hossain said.
The rescue ship Rostom has reached at the spot at 9:30pm, he added.
The rescuers are trying to trace the sunken launch from 1 km to 2km in the south from Mawa ghat in the Padma River.
The launch was heading towards Mawa ghat from Kawrakandi, said the BIWTA official.
The divers' team of Navy, fire service and coast guard are conducting a search and rescue operation.