In the past, before the advent of motor vehicles on land, large barge-type cargo boats were used in Southern Kerala Backwaters for transport of cargoes like coconuts, copra, coir, fish, pepper, ginger and general merchandise to and from towns and villages on the shores of the extensive lagoons, rivers, estuaries and natural and man-made canals.

Typical cargo boats, called 'Kettu-vallom' in local language (Malayalam) were 20 - 25 meters long and 4 - 4.5 meters wide, with a load-carrying capacity of about 30 tonnes. Two or three truckloads of cargo could be accommodated in a single cargo boat. These transport vessels were moved by rowing with oars or paddles in places where the lake is deep and by long bamboo poles where water is shallow.

For centuries, the waterways in Kerala served as routes for travel and transportation. Roads and carts linked the hinterlands of Kerala with the boat jetties at different places in the villages and towns in the lowlands. The importance of the waterways declined with the advent of motor vehicles in Kerala in recent years. Cars, buses, trucks, two and three wheelers, with their advantages of speed and convenience, became the preferred means of transport and travel, leading to neglect of the waterways.

Now, the waterways are renovated, widened and deepened to facilitate inland navigation. Old cargo boats are finding new uses in the tourism sector, in the form of houseboats.