Something slightly related, but mostly of a tangential interest:

https://en.wikipedia.org/wiki/Tamil_bell

The Maori population also having descended from the Pacific Island Polynesians.

Fascinating trivia: Madagascar was populated by the Polynesians

https://en.wikipedia.org/wiki/History_of_Madagascar#A_common...

No, it was people from Sunda Islands (now Indonesia) who are also austronesians.

Moari polynesian

It’s possible, but imagine you find a decrepit alien structure on the shoreline. You’ve never encountered it before. Do you think this broken down structure is going to easily give you answers? Do you think you’ll be able to recreate its building techniques without guidance to build a fully working one (even though this one may be incomplete)? I think this scenario is less likely than being trained by a fellow human. Unfortunately, unless there is evidence of genetic admixture it may remain uncertain.

The simpler theory is simultaneous invention.

Little hard to prove either though.

We do have a lot of tar washing up on the beach around here, which is a needed to make a Chumash canoe. Available resources determines what you can make, too.

The amount of stuff that drifted and washed up on BC, WA, OR beaches after the 2011 tsunami was quite varied. It's not entirely impossible that some canoes went adrift and later ended up on Pacific Northwest beaches...

True. That, too, is an interesting hypothesis.

Traders from Chile are another option.