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Comment by curtis | Hacker News Reader

The winds in the South Pacific predominately blow east to west. Since Polynesian voyaging canoes have a very limited ability to sail into the wind, it seemed impossible for them to have colonized Polynesia from west to east. This appeared to be a pretty strong argument for a colonization of Polynesia from South America, since South American voyagers (either intentional or accidental) would be sailing with the predominate winds, not against them.

However, it turns out that during El Niño years the direction of the winds can change so they are blowing from west to east, making it much easier to sail east across the South Pacific.[1]

In 1947 Thor Heyerdahl didn't know about this possibility.

[1] Anomalous Westerlies, El Niño, and the Colonization of Polynesia - https://www.jstor.org/stable/677659?seq=1#page_scan_tab_cont... (I can't find the full text of the paper online, but I think this is the one I remember.)

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They sailed west to east on purpose, because it made it easier to get home if they didn't make landfall.

The canoes they used were not tacked, they were shunted, which made it much easier to said into the wind.

To get back home, they memorized a bunch of zenith stars for their home latitude, went north or south till they put those stars at zenith and then just let the wind carry them home.

Non instrument navigation to Hawaii, for example, involves overshooting the island chain by going a bit too far east, putting Hokulea (Arcturus) at the zenith then sailing west till you make landfall.

I should have thought of it before, but it occurred to me that Hokule'a (the canoe) has been all over Polynesia, so they had to handle sailing east for part of those trips.

This led me to this article about their first trip to Easter Island, sailing from Mangareva:

http://www.samlow.com/sail-nav/giftofthewind.html

They expected the voyage to be difficult because it would be almost directly into the prevailing winds, but it turned out that they were able to sail pretty close to due-east the entire trip and they arrived at Easter Island 10 days early.

This was in 1999 which was not an El Niño year, but rather a La Niña year following the really large 1998 El Niño event.

I don't think shunting buys that much. The crab claw sail is still limited in how close it can sail to the wind. It's always going to be easier sailing when the wind is favorable. And it turns out that in some parts of some years, the winds are more favorable for sailing east in the South Pacific. Of course sooner or later the prevailing winds will return, and then it will be easier to get home.

IIRC shunting meant that they could keep the outrigger down wind at all times, which is supposedly more efficient than sailing an outrigger canoe 'the wrong way' half the time.

I had to look "shunting" up -- I'd heard of it before but then forgotten.

The big oceangoing voyaging canoes like Hokule'a are double canoes so they are symmetric, unlike outrigger canoes. There still might be an advantage to shunting depending on what kind of sail the canoe is using. According to Wikipedia, some types of lateen sails (of which the crab claw sail is a variant[1]) suffer from a "bad tack" due to the position of the mast[2], which shunting would address.

I don't think hokule'a is shunted, but I'm not actually clear on that. Hokule'a isn't a perfect replica anyway since it's built of modern materials.

[1] https://en.wikipedia.org/wiki/Crab_claw_sail

[2] https://en.wikipedia.org/wiki/Lateen (look for "bad tack")

Hokulea is not shunted, but it is a decent replica of a double hulled Polynesian ocean canoe.[1]

The craft that were shunted were the smaller outrigger canoes.

[1] When it is rigged with lateen sails. It often is rigged with a Bermuda sail.

>The canoes they used were not tacked, they were shunted, which made it much easier to said into the wind.

I googled "canoe shunted" and these were some links:

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

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

Interesting technique (shunting - need to read more about it), as is tacking. I remember first reading an explanation of how tacking works, i.e. of how ships and boats are able to sail (almost) towards the wind, in terms of two resolutions of forces (which I had just learned about somewhat recently in high school physics), one being of the wind against the sail (which is at an angle to the wind), and the other being of the movement of the boat at an angle against the keel, or something like that. If it had not been for the explanation of the two resolutions of forces and the result (enabling tacking), I would not have believed that a ship/boat can sail upwind (unless I had seen it).

Also, adding my 2c to the discussion about Polynesian navigators (I posted about this in an HN thread some months / years ago): the National Geographic magazine had done an extensive study years ago, in Polynesia and maybe Micronesia, about these ancient navigators and their methods, such as using the waves and patterns in the sea, swells, land, mirages, sky, clouds, birds, etc., to navigate and find their way between those islands separated by thousands of kilometers. They interviewed some of the surviving descendants of the ancient navigators, some of whom were themselves still navigators.

And related, the other point I had mentioned on HN (in a similar context) earlier, was the novel The Navigator, by Morris West, which is a great adventure story, involving threads talking about such ancient navigation practices, psychology in practice, social experimentation and other interesting stuff, all well woven together into the narrative by the author, who also wrote The Shoes of The Fisherman and a few other bestsellers.

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

Also:

Hōkūleʻa:

https://en.wikipedia.org/wiki/H%C5%8Dk%C5%ABle%CA%BBa

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

You might like the book 'Vaka Moana' if you haven't read it yet.

Just saw this (among other things) after searching for Vaka Moana:

https://okeanos-foundation.org/vaka-moana/

https://okeanos-foundation.org/foundation/

Vaka Moana means 'ocean canoe.'

Got it. I like the sounds of the Polynesian languages.

Thank you, will check it out.

Another good source, mentioned above, is Pathway of the Birds https://www.goodreads.com/book/show/41112497-pathway-of-the-...

Something I recall from reading "Sail Performance", the crab claw is way better then most people expect. In fact for a smaller boat it may just be the best shape when averaged over all the points of sail. Modern sail plans are targeted more towards large boats and racing boats, which does not reflect the reality of what most people are sailing most of the time.

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

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