Made the mistake of going "whale watching" while in Sri Lanka. (Galle)
The boats -- operated by "Sri Lanka Boat Oparator Society for the whale & Dolphins Protecting and Watching" (typos theirs) -- are packed with tourists (many of whom are required to sit on the floor -- for hours -- on thinly cushioned mats).
The tour itself, which can range from 2-6 hours depending on whether or not whales are sighted, will run you about $45 (Rs 6000).
During the course of the trip, customers are offered bottled water, sandwiches, bananas and crackers. But trust me, that gesture does little to assauge the utter discomfort and disappointment. (We did manage to see a few whales from a distance. But given that there were some 24 tourist-packed boats and other vessels pursuing the poor creatures, all vying for an optimal vantage point, our view wasn't that great and the whole experience came off horribly cruel and exploitive.)
I would pass if I were you.