Vallamkali is the famous boat race conducted along with onam festival. Vallam Kali include 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. At Aranmulla, where there is a temple dedicated to Lord Krishna and Arjuna, thousands of people gather on the banks of the river Pamba to witness the exciting Snake Boat races. Nearly 30 Chundan Vallams or snake boats participate in the festival. Owned by villages bordering the river from the hills to the low lying plains- a stretch of about 40 kilometres - these boats are steered by oarsmen dressed in white dhotis and turbans. Singing traditional boat songs, the oarsmen splash their oars into the water to the rhythm of the songs. They guide their boats to cruise along, seemingly like a fish on the move. The golden lace at the head of the boat, the flag and the ornamental umbrella at the centre make it a spectacular show of pageantry. Though ostensibly a competitive event, the festival is more a visual extravaganza.
To date on the eve of Thiru Onam, the boat Palliodam floats down from Katoormana to the accompaniment of blowing of conch shells, music and drum beating. Torches are lit and snake boats accompany the procession. The colorful boat festival is held on Uthruttathi or the fifth day after Thiru Onam.
Each snake boat belongs to a village along the banks of the river Pamba and is worshipped like a deity. Only men are allowed to board or even touch a boat and that just barefoot. Every year the boat is oiled mainly with fish oil, coconut shell, and carbon, mixed with eggs. The black mixture keeps the wood strong and the boat slippery in the water. Annual repairs are carried out lovingly by the village carpenter and people take pride in their boat, which represents their village and is named after it. Tradition demands that the Nambudiri Brahmin be at the main rudder oar about 12 feet long. There are four main oarsmen who control the movement of the boat. And in minutes the boat can turn around just by the twist of the hand by the chief oarsman. In the old days the villagers used to sit in the boat in order of their castes but today the order is changing though a certain pattern can still be distinguished. Everyone- the carpenter, the barber, the goldsmith, the blacksmith as well as the agricultural labourers - all have a place on the boat. And in close harmony and magnificent synchronization they pull at the oars.