In the end we had a very nice time in Tubuai. The anchorage in the west was so calm that we could get some work done and then we met a friendly Polynesian while hitchhiking: He offered to take us up Mt Pahatu (we had failed on our own) and it turned out, there is indeed no path–but Grandpa Viri made one for us with his machete 
Today at noon we left with northeasterly winds. The passage to Raivavae (105 nm) will take us over the Tropic of Capricorn, so we’re officially leaving the tropics.
