A molded tablet from Mohenjo-daro ca. 2300 BCE, below while above, flat bottomed ferry boats are still used today to help travelers cross the Indus River near Mohenjo-daro. The boat on the seal is part of "a three-sided molded tablet, with boat, gharial and script. One side is a flat-bottomed boat with a central hut that has leafy fronds at the top of two poles. Two birds sit on the deck, and a large double rudder extends from the rear of the boat." (Kenoyer, Ancient Cities, p. 192)
See also An Indus Boat Seal and Indus-style Boat.