The DNA evidence suggests the opposite, in fact.

Many lines of evidence, linguistic, genetic, cultural suggest that polynesia was colonized west to east, probably originating in ancient Taiwan.

Heyerdahl pulled of an impressive feat, but his raft was a real dogs breakfast compared to a voyaging canoe or flying proa.

Doesn't the DNA evidence now suggest both? The article says that polynesian populations show a DNA connection with the Americas (especially around Columbia) from sometime around 1200. It would seem that the polynesians sailed from West to East until they either hit the American continents or peoples from the American continents came out and met them. Or both.

The article also suggests some think it might just be the effect of their most recent common ancestor in Asia somewhere, and not from any kind of transplant.

The American continents are kind of hard to miss. After sailing east from tiny island to tiny island, it is kind of hard to believe that they didn’t run into the continents at some point while looking for new islands.

Maybe, maybe not. Easter island is one of the most isolated islands in the world and is also one of the easternmost islands in the Pacific. It's still a long way to go to get to South America from there. Maybe a few family units arrived and then forgot about boat building and navigation for a few generations because the islands land resources were so plentiful. I think something similar happened to native people on Tasmania - they took a boat to get there, but forgot how to build boats eventually and so were stuck on their island without the ability to go to mainland Australia.

David Lewis’s book, We the Navigators, provides an in-depth study of polynesian/melanesian/micronesian boats and navigation methods and is the best source I have found on the subject

It's my understanding that serious anthropologists have little but laughter and disdain for Heyerdahl. Perhaps because his methodology was less than exactly scientific, but also due to a number of later spurious claims he made with no evidence.

While that is true, a whole lot of anthropologists when he went on his first expeditions also laughed at the idea of pre-European contact across the pacific, and whether or not he was right about who visited who the evidence that his claim that there was pre-European contact was true keeps piling up.

Of course he certainly went too far with respect to many of his claims, but he's not the only one with egg on their face in that respect.

I don't know how else people think maori's got their kumara but im keen to hear it.