score:5
in kanyakumari, if you want to see the normal places like Vivekananda memorial etc, ferry services are available from morning 8 to evening 5 but depends on low tide/high tide and timing changes.
For your personal seeing in the seas, there are very few options there and you need to negotiate everything else from timings to fare etc generally. Last time, I visited Kanyakumari 6 months back, i did not found any place where they take you on personal tours in sea.