To study ancient seafarers, researcher built a replica ship and sailed it(washingtonpost.com)
washingtonpost.com
To study ancient seafarers, researcher built a replica ship and sailed it
https://www.washingtonpost.com/history/2022/09/17/seafarers-mediterranean-wind-david-gal/
46 comments
Yeah, I came to mention the Kon-Tiki: https://en.wikipedia.org/wiki/Kon-Tiki_expedition
These are things that National Geographic readers of a certain age were all very familiar with.
[deleted]
His (Thor's) books are a cracking read too.
He was the original gonzo anthropologist
I would like to mention Thor Heyerdahls expeditions
In 1947 he crossed the Pacific Ocean on the balsawood raft Kon-Tiki.
This was his first expedition to be captured on film, and was later awarded Academy Award for best documentary
In 1951. He later completed similar achievements with the reed boats Ra, Ra II and Tigris.
https://www.britannica.com/biography/Thor-Heyerdahl
https://www.kon-tiki.no/thor-heyerdahl/
https://en.wikipedia.org/wiki/Thor_Heyerdahl
In 1947 he crossed the Pacific Ocean on the balsawood raft Kon-Tiki.
This was his first expedition to be captured on film, and was later awarded Academy Award for best documentary
In 1951. He later completed similar achievements with the reed boats Ra, Ra II and Tigris.
https://www.britannica.com/biography/Thor-Heyerdahl
https://www.kon-tiki.no/thor-heyerdahl/
https://en.wikipedia.org/wiki/Thor_Heyerdahl
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...
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...
Along these lines let's not forget the Kon Tiki expedition. In 1947 Heyerdahl & crew wanted to show if, using a simple raft, South Americans could have reached Polynesia in the era prior to Columbus in 1492. Modern genetic analysis now seems to back up his idea long after he made his successful voyage.
https://www.kon-tiki.no/expeditions/kon-tiki-expedition/ https://en.wikipedia.org/wiki/Kon-Tiki_expedition
https://www.kon-tiki.no/expeditions/kon-tiki-expedition/ https://en.wikipedia.org/wiki/Kon-Tiki_expedition
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.
> 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.
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.
[deleted]
It took me a loooong time to intuitively understand how a ship can sail upwind. The diagrams and explanations made no sense to me.
I finally figured it out, though. Take a drafting triangle, which has 30-60-90 degree angles. Place the 30-90 side against a wall or something rigid. Take a block (wind) and press on the 30-60 side. The triangle will squeeze "upwind" in the direction perpendicular to the 30-90 side (in addition to a larger movement sideways towards the 60-90 side).
The keel of the boat plays the role of the 30-90 side against the wall, the sail the 30-60 side.
I finally figured it out, though. Take a drafting triangle, which has 30-60-90 degree angles. Place the 30-90 side against a wall or something rigid. Take a block (wind) and press on the 30-60 side. The triangle will squeeze "upwind" in the direction perpendicular to the 30-90 side (in addition to a larger movement sideways towards the 60-90 side).
The keel of the boat plays the role of the 30-90 side against the wall, the sail the 30-60 side.
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!
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!
Get it wrong and glub glub goodbye cruel world!
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.
“Modern” things ;)
It’s been 94 years since Uffa Fox built the (planing) Avenger and thoroughly destroyed his British competition on the Isle of Wight. And then took that little 14-footer across the channel to do the same to the French.
All because the elitist snobs didn’t want him to join their club :)
It’s been 94 years since Uffa Fox built the (planing) Avenger and thoroughly destroyed his British competition on the Isle of Wight. And then took that little 14-footer across the channel to do the same to the French.
All because the elitist snobs didn’t want him to join their club :)
The most mind blowing down “wind” sailing I’ve ever seen: https://m.youtube.com/watch?time_continue=13&v=q2il8Fagbyk&f...
> 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 is true for any rigid body traveling through a fluid. It comes up in ballistics too.
This is true for any rigid body traveling through a fluid. It comes up in ballistics too.
"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"
Is there a simple explanation for this to share?
Is there a simple explanation for this to share?
As a boat moves through the water it creates a bow wave. The wavelength (ie crest to crest) of the bow wave increases with boat speed. Once the wavelength of the bow wave equals the hull length, the boat will start climbing the front of the bow wave and will be sailing up hill. Unless you've got a lot of power and can climb on top of the bow wave and plane, this is the maximum hull speed.
Best explanation I have ever read for that.
Longer => greater surface area in contact with the water.
Friction and stiction due to area is a greater killer of speed than weight, which will only put you a bit lower in the water.
It is obviously a lot more complicated than that. Enough weight will sink you and more length will slow your descent to the depths a bit. Greater weight will increase inertia so acceleration will take a hit. Depending on how the weight is distributed you risk turn over due to your meta centre being in the wrong place in relation to your centre of gravity.
Friction and stiction due to area is a greater killer of speed than weight, which will only put you a bit lower in the water.
It is obviously a lot more complicated than that. Enough weight will sink you and more length will slow your descent to the depths a bit. Greater weight will increase inertia so acceleration will take a hit. Depending on how the weight is distributed you risk turn over due to your meta centre being in the wrong place in relation to your centre of gravity.
> Longer => greater surface area in contact with the water.
>Friction and stiction due to area is a greater killer of speed than weight, which will only put you a bit lower in the water.
The opposite is true.
The longer a hull, the faster a displacement vessel can travel. Here's an MIT explanation: https://engineering.mit.edu/engage/ask-an-engineer/what-is-t...
>Friction and stiction due to area is a greater killer of speed than weight, which will only put you a bit lower in the water.
The opposite is true.
The longer a hull, the faster a displacement vessel can travel. Here's an MIT explanation: https://engineering.mit.edu/engage/ask-an-engineer/what-is-t...
you might find this video helpful: https://www.youtube.com/watch?v=URgSFglbl5g
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.
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.
Thanks for this example, I had a hard time envisioning it, too.
In the Mediterranean Sea the winds predictably reverse (and have for centuries) so sailors would schedule around when they were blowing favorably in the right direction.
They might wait days within the cycle to get the best conditions.
You're welcome.
They might wait days within the cycle to get the best conditions.
You're welcome.
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.
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.
I have now actually read the article. It seems that no sailors were harmed in it.
I really don't buy this article's premise.
Even a vessel with run only sails can plot a course by working out which bit of land is affecting the patch of sea they are traversing. In the areas where land doesn't have a direct effect, you get to play the usual lottery with wind and weather. Even when the wind is against them, they should be able to manage slightly better than a "abeam close reach" so go slightly against the wind.
"Modern mariners can tack against the wind by setting the sails at sharp angles. That wasn’t feasible 2,400 years ago because sails were fixed then."
No they were not "fixed" at all - look at the picture of the replica - it is running close hauled. The sail is tied off fore and aft and not at right angles to travel. The article literally contradicts itself with photo evidence. If you look really closely at the modern yacht with a Bermuda rig - it's sails are luffing!
I really don't buy this article's premise.
Even a vessel with run only sails can plot a course by working out which bit of land is affecting the patch of sea they are traversing. In the areas where land doesn't have a direct effect, you get to play the usual lottery with wind and weather. Even when the wind is against them, they should be able to manage slightly better than a "abeam close reach" so go slightly against the wind.
"Modern mariners can tack against the wind by setting the sails at sharp angles. That wasn’t feasible 2,400 years ago because sails were fixed then."
No they were not "fixed" at all - look at the picture of the replica - it is running close hauled. The sail is tied off fore and aft and not at right angles to travel. The article literally contradicts itself with photo evidence. If you look really closely at the modern yacht with a Bermuda rig - it's sails are luffing!
Before the lateen sail.
https://www.britannica.com/technology/lateen-sail (and a deep keel)
https://www.britannica.com/technology/lateen-sail (and a deep keel)
Yet, without such favorable conditions to develop sailing, would the lateen have been invented? (technology ladder theory)
The more we learn about the Mediterranean, the more I am struck that it was the perfect crucible, and that it is no accident it was the epicenter of so much in human history.
The more we learn about the Mediterranean, the more I am struck that it was the perfect crucible, and that it is no accident it was the epicenter of so much in human history.
People were sailing out of sight of land at least 40,000 years ago around southeast Asia, and possibly even up along the Aleutians and down the West coast of the Americas.
What we are certain about is that they reached Australia. There was never any way to get there except via multiple such crossings.
Whether this happened via Sulawesi and Papua New Guinea, or via Bali, Lombok, and Timor, or both, nobody knows. But at the time Papua New Guinea, Australia, and Tasmania were all one island we call Sahul, and most of the sea between Indonesian islands was rich river bottom land, going on a million square miles of it we now call Sundaland, connecting with Taiwan and what is now all beneath the South China and Yellow seas all the way to Korea.
People lived there for tens of thousands of years before the sea began to rise 20,000 years ago, continuing until 8000 ya, 200m in all, with 80m between just 12,000 and 8000 ya. The oldest cave paintings we know of are in what were then the mountains of Sulawesi, hauntingly similar to what shows up all over Europe from Czech to Spain tens of millennia later.
When the water rose, people had to move uphill to where other people were already living. Australian oral histories still record resolutions of conflicts over that event.
What we are certain about is that they reached Australia. There was never any way to get there except via multiple such crossings.
Whether this happened via Sulawesi and Papua New Guinea, or via Bali, Lombok, and Timor, or both, nobody knows. But at the time Papua New Guinea, Australia, and Tasmania were all one island we call Sahul, and most of the sea between Indonesian islands was rich river bottom land, going on a million square miles of it we now call Sundaland, connecting with Taiwan and what is now all beneath the South China and Yellow seas all the way to Korea.
People lived there for tens of thousands of years before the sea began to rise 20,000 years ago, continuing until 8000 ya, 200m in all, with 80m between just 12,000 and 8000 ya. The oldest cave paintings we know of are in what were then the mountains of Sulawesi, hauntingly similar to what shows up all over Europe from Czech to Spain tens of millennia later.
When the water rose, people had to move uphill to where other people were already living. Australian oral histories still record resolutions of conflicts over that event.
Maybe, maybe not, but there are other ways to sail upwind, such as the proa https://en.wikipedia.org/wiki/Proa .
When it comes to basic applications of fundamental machines (this is ultimately a use of leverage), humans have a way of figuring it out.
When it comes to basic applications of fundamental machines (this is ultimately a use of leverage), humans have a way of figuring it out.
“Modern mariners can tack against the wind by setting the sails at sharp angles. That wasn’t feasible 2,400 years ago because sails were fixed then.”
From the picture it seems the sail on the replica can pivot around the mast but looks like it would take a lot of work (and time) with all the rigging.
So is this quote’s meaning that modern sailboats can change the angle of its sail fast enough to be useful while the ancient ones couldn’t?
From the picture it seems the sail on the replica can pivot around the mast but looks like it would take a lot of work (and time) with all the rigging.
So is this quote’s meaning that modern sailboats can change the angle of its sail fast enough to be useful while the ancient ones couldn’t?
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.
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"
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"
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.
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.
It's too much to expect an academic to engage SMEs
>Mappings of Potential Sailing Mobility in the Mediterranean During Antiquity
https://link.springer.com/article/10.1007/s10816-022-09567-5
https://link.springer.com/article/10.1007/s10816-022-09567-5
It's somewhat tangential but I heartily recommend the Poul Anderson short story "The Man Who Came Early"
I think this is pretty common.
They attempted to cross the Atlantic on papyrus boats, based on drawings and models from ancient Egypt.
Here's a good picture of their second boat:
https://upload.wikimedia.org/wikipedia/commons/0/09/19-08-28...
Here's the documentary:
Part 1: https://www.youtube.com/watch?v=EJDYiTYoaLE Part 2: https://www.youtube.com/watch?v=hb6Jsudv7lg