Kettuvallam Houseboat Architecture of Alappuzha Backwaters

The Kettuvallam (literally "boat made of knots") is the iconic houseboat of Alappuzha's backwaters, originally a cargo vessel used to transport rice, spices, and other goods through the 1,500 km network of canals and lakes. The vessel is constructed without nails — the hull planks are tied together with coconut coir rope and caulked with a mixture of tar, fish oil, and cashew resin, a technique developed by traditional boat builders (Mudaliar craftsmen) over centuries. The structure above the hull uses a bamboo and palm frond framework. Modern tourism has transformed Kettuvalloms into luxury floating hotels, but the coir-lashed hull construction method is maintained as a cultural heritage technique by the Alappuzha boat builders' association.