The Vaeanu and Hawaiki Nui ferries are cargo ships with passenger cabins. The Vaeanu is very old, but it is larger, carrying 90 passengers. The Hawaiki Nui is the smaller one, carrying only 12 passengers.
Fares are for deck or cabin. We strongly recommend getting a cabin. These ships do not dock at the passenger ferry port. You’ll find them on the other side of the bay on Motu Uta (see a Map of Pape'ete). It's a bit far, and you'll need to take a taxi.