The hull is a series of wooden planks, long cut and carved by the expert hands of the carpenter, tied together using coir with coconut fibers stuffed in between. Kettuvallam is steered by two persons in deep waters by means of oars. Long bamboo poles or 'punts' are used to propel in shadow areas. Bamboo beams sprouting off on the sides are used as foot holds for the same a senior oarsman and a helper control the Kettuvallam by singing songs and chants for inspiration. A box of sand, a few bricks in interior facilitate cooking on lower racks, with storage on the upper ones. Food and necessary items are stored in shelves sleeping quarter is on the uppermost racks, which have the best ventilation and accessibility. The interior space can also be used for the same when there is no cargo. Fresh water is stored in earthenware pots.
Basically Kettuvallam was designed to transport cargo to various destinations in Kerala. When it was used for tourist purpose, there new problem cropped up like - No free movement was possible because the floor area of the hull was very less. The space below the hull was more compared to the space above. There were no openings, which provided enough of light, air or view towards outside. The tourist felt it difficult to walk through the length because the curved shape of the hull with Manikals coming across. The roof was made of thatch, which was not properly done so during rain leakage was likely. Due to the low head clearance of the Valavara it was only possible to sit on the padi of the hull. Since the Valavara was low, the airflow through the Vallam minimum. The hull is curved and for the beginners it was very difficult to balance when the vallam was in motion.