“We don't build new boats from scratch any more,” says 68-year-old Govindan Ashari, a boat builder for almost half a century, whose boat yard is perched along the palm-studded western shore of Kerala's Lake Vembanad, across from Coconut Lagoon. "But when we did, we'd first scrape a rough outline on the ground for the prospective owner, then prepare a more refined 'blueprint' on a plank of wood. The formula is always calculated in the same way, starting with the desired width: the length is roughly six times that, the depth about one-half the width."

Seasoned, naturally curved logs of anjili (the jackfruit artocarpus hirsutus) are used for replacing worn planks. As a concession to modern times, bolts are now used to secure the ribs, but the rest is still stitched in the traditional manner, the coir rope threaded through the base of a large 'needle' carved from a palm frond. Other primitive tools are still in use in the trade after all these centuries, including the notched branch of a tree uses as a vise for aligning planks.

“We punch holes every 7.5 cm (3 inches) along the length of each plank, 2 cm (three-quarters of an inch) from both edges," Ashari explains. "To join two planks we first make a diagonals stitch to the left, then one to the right, and then make a vertical stitch." This process is repeated along the entire length of the boat, using hand-spliced four-meter (12') sections of coir rope. Hand-rolled coir plugs are hammered into the holes and a combination of raw coir and coir rope, later soaked in sardine or cashew oil, is rolled to the desired thickness and laid along the lateral seams for caulking. In an earlier era boat builders made their own rope: nowadays they buy it. The kettuvallams converted in Ashari's boat yard are now operated as exclusive single-stateroom houseboats by Spice Coast Cruises.