Vallam Kali includes races of many kinds of traditional boats (paddled longboat) of Kerala. The race of Chundan Vallam (snake boat) is the major event. Hence Vallam Kali is also known in English as Snake Boat Race and now in recent years has become a major tourist attraction. Other types of boats which do participate in various events in the race are Churulan Vallam, Iruttukuthy Vallam, Odi Vallam, Veppu Vallam (Vaipu Vallam), Vadakkanody Vallam, Kochu Vallam. The Nehru Trophy vallamkali winner for the 2008 is Karichal Chundan (chundan = snake boat.)
Snake boat races are the highlight of the Onam Festival in August/September, particularly the Aranmula Boat Race, which takes place mid way through the 10 day celebrations. Many other boat races are also held during the festival along the backwaters at Kottayam, Payippad, and Champakkulam. The Champakkulam Moolam is held in June/July, and the Payippad Jalotsavam is held in September.
Vallamkali boat are no ordinary boats and there are fixed measurements to it. It is about 100 feet long and has a seating capacity of 150 men. The boats are usually made of anjili (Artocarpus hirsuta), though sometimes teak and kadamb (Naucleacadamba) wood is also used. The curled ends of the boats are shaped like cobra hoods and it is from this shape that boat has derived its name. Each boat is meticulously crafted by skilled craftsmen and a lot of patience and hard work goes into making and decorating it. The boat is treated as a deity and a holds a lot of emotional value for the village folk. Only men are allowed to touch the boat that too with bare feet. Each boat belong to individual villages located near the river Pamba.
Vallamkalis are tastefully decorated with green and scarlet silk umbrellas. The number of umbrellas attached to a boat holds significance as it signifies the affluence of the family to which they belong. To render a more maginificient look to the boat gold coins, ornaments and tassels are also added.
Great care is also taken for the upkeep of the boat. A carpenter repairs the boat on an annual basis. The boats are lubricated with fish oil, coconut shell and carbon mixed with eggs. This also helps to keep the wood strong and boats slippery in water. This way one can always find a boat ready for a swim