To study ancient seafarers, researcher built a replica ship and sailed it

Yeah, I came to mention the Kon-Tiki: https://en.wikipedia.org/wiki/Kon-Tiki_expedition

His (Thor's) books are a cracking read too.

He was the original gonzo anthropologist

A similar attempt to recreate a historic to happened recently with a descent of the Grand canyon on a tule reed boat of sorts.

https://www.blm.gov/blog/2021-02-24/tule-reed-boat-runs-gran...

There's a video here https://www.adventure-journal.com/2021/03/did-indigenous-pad...

I think modern genetic analysis has proven Thor Heyerdahl wrong. From the linked article:

> Heyerdahl's hypothesis of Polynesian origins is overwhelmingly rejected by scientists today. Archaeological, linguistic, cultural, and genetic evidence all support a western origin (from Island Southeast Asia) for Polynesians via the Austronesian expansion.

There was a great movie shot by the sailors before and during their voyage, I think called Kon-Tiki, and released in 1950 ( https://en.wikipedia.org/wiki/Kon-Tiki_(1950_film) ). It used to be up on Youtube, but I can't seem to find it. If anyone can dig up a link, it's very worth a watch. IIRC, they're almost hilariously casual about the whole thing, and they just went and crossed the Pacific on a raft of logs, with little support.

It was a bit more than "could have reached Polynesia."

As your Wikipedia link points out:

> Heyerdahl's hypothesis was part of early Eurocentric hyperdiffusionism and the westerner disbelief that (non-white) "stone-age" peoples with "no math" could colonize islands separated by vast distances of ocean water, even against prevailing winds and currents. He rejected the highly skilled voyaging and navigating traditions of the Austronesian peoples and instead argued that Polynesia was settled from boats following the wind and currents for navigation from South America.

As a sort of mirror image of Kon-Tiki, the 1976 Hōkūleʻa trip from Hawaii to Tahiti - using traditional non-instrument wayfinding methods from one of the last Polynesian master navigators, Mau Piailug - conclusively demonstrated that viewpoint wrong.

I got into sailing for a bit (poor man’s sailing in a 16’ sailing kayak), and it took a lot of mental processing for me to realize how the keel (or a form of hull acting as a keel) is essential for sailing upwind. The physics are really interesting.

I used to sail and fairly quickly got the understanding for sailing up-wind. The thing that blew my mind, and continues to, is that the top speed you can reach is dependant upon the length of the boat and not the weight. This obviously excludes modern things like motorised craft, planing, foiling etc.

When it comes to explaining how keels allow sailboats to point close to the wind, I always liked "squeeze a watermelon seed, it shoots forward" as a way to make it more intuitive.

If you look down on a bermuda rigged (big triangle) sail from above, it looks suspiciously like an aerofoil and those things fly. There is an angle away from the wind coming towards you which is as "close as you can get to the wind". At that point you are "close hauled", Try and go closer to the wind and your leading edge will collapse (luffing) and you will slow down rapidly and it gets a bit rubbish.

As you move away from the wind your speed will increase because of several things: less of the wind vector is trying to blow you sideways and more is actually pushing you. The aerofoil lift thing is less important compared to being pushed. The sweet spot is at around 120 degrees off the wind - there is loads of push and loads of "lift" and a minimal amount of sideways force being counteracted by the hull. This is called a "broad reach".

When the wind is behind you "running", there is a lot of push and no "lift" but instead you get drag due to the break up of laminar flow over the wing errr sail. However, in a run you send up spinnakers and "big boys" which are all basically bloody great bags to capture the wind and massively increase speed. Even a small yacht can "goosewing" by putting up two of the front sails - one on each side to increase sail area.

I've done about 30mph on a wind surfer in a broadreach - my mum drove along a road parallel to the beach and the wind was just right to do a broad reach roughly parallel to the beach and road. A car speedo is usually 10% shy of reality.

Sailing is great fun and can be really complicated but once you know your halyard from your sheet and all that stuff and get to the point where you can feel the wind and can see the conditions on the water and all the other things going on it is rather rewarding. The point of going from novice to supervised fun is quite quick - a weekend or so in a dinghy. A couple of weekends to be confident solo inland and a bit longer at sea. You do need to think safe.

Get it wrong and it can be a right old downer!

Thanks for this example, I had a hard time envisioning it, too.

Before the lateen sail.

https://www.britannica.com/technology/lateen-sail (and a deep keel)

The Middle of the World sea is mostly land locked. Close to land the winds run off shore (away from the shore) in the morning and then back to on shore (point towards the shore) in the afternoon. This is because in the morning the land is relatively cool and in the afternoon it is relatively warm. The thermal gradient above the land and sea then determines the wind direction. This pattern is mostly seen in the summer and less so in the other three seasons, when it gets a bit more random.

Now it all gets a bit complicated depending on which bit of sea is being affected by which bit of land. On top of that the Med has weather systems just like everywhere else and they can get a bit feisty. Early in the (Christian) New Year you get the big old winds like the Ghibli and co dumping sand into your Brandy Sour.

I lived in Cyprus for two years back in the 1980s and spent quite a lot of that time in and on the water.

square rigged vessels cannot make way upwind; they are limited to approximately 60 degrees either side of the wind, and would have terrible sailing characteristics in this position that would push them downwind to the level that they could probably not travel a true course within even 90 degrees of the wind.

lateen (think dhow) sails were around from about 200 bc but only became widespread later. They are more efficient efficient upwind and permit a boat to point close enough to the wind to move a meaningful distance "upwind"

There was more to it than just sails. Keel and rudder tech had to evolve too. Tacking a ship upwind is a special thing that involves every aspect of sail and hull to accomplish. And the equipment to do it comes with drawbacks.

lol.

You are quite correct - that boat isn't the same as a modern one and you've spotted it. The sail is fixed fore and aft (sheets) and it looks like you move the sheets around as you need. It has a yard which we assume works like our usual square rigged vessels but it doesn't. That vessel can work upwind a bit.

Zoom in on the modern yacht in the photo. It's staysail (front triangle) is luffing slightly (laminar flow is broken). That means that the old boat is working fine at the same point of sail as the modern boat. The old boat probably doesn't have a decent keel so will slide sideways a bit.

This sort of analysis needs proper sailors involved and it looks like none were.

Run!