That’s the best the Wiki can do to explain what a “kettuvallam” is. To me, “kettuvallam” is a taste, an experience!
On your way from Kaloor junction to kadavanthra, set amidst a wide range of potholes and “very similar to ponds” kind of road (a common scenery seen right after you pass coimbatore on NH47 right up to Kanyakumari), is “kettuvallam” a nice food joint that specializes in sea food. The ambience there is wonderful, because the restaurant itself is designed like a house boat (that’ll be the first thing you’ll notive about it), and with a nice illumination work done, gulping down tiger prawns curry and kerala style porotta will sure be an experience you’ll enjoy.
I’ll very much recommend these guys if you are looking for spicy kerala style sea food, and yes, they have everything printed on the menu card readily available anytime, unlike most restaurants.
More photos here