Hi was there in Havelock a week back .If its a sudden plan the flight will cost you around 30k for 2. If you book in advance wil cost 23k around . From portblair up and down ferry 5500 for 2 .
3500 is min cost for a night. If its 3 nights around 11k .
Other transports 4k . water sports u can spent 10k for 2 .
Havelock is expensive