Port Villa to Luganville? or reverse?

G'day, we are headed to Vanuatu in a month or so and landing at Port Villa.
Thinking of flying to Santo (Luganville) for a few dives and a look around and then boating it back to Port Villa.
Any tips on local ferries, boats available to island hop back down and/or any idea how long a straight boat trip back might take?
Thanks in advance.
CJ and Angie

The boat trip from Luganville to Santo is about 24 hours. It's filthy, full of animals, people, cargo piled to the ceiling and there's NO place to sleep :) It's often delayed or canceled and costs about half the air fare. On the other hand it's a great way to meet locals. Your choice :)

The boat I took took 3 days to get to Santo.
To avoid unpleasant delays, it is probably better to take the flight back to Vila!

Thanks for the information.
We decided after all the input we got to Fly direct to Santo, transfer to Villa and a Unity Flight to Tanna and back.
Cheers,
Cj adn Angie