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  #91  
Old 11-27-2013
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Re: Open letter to yachtdesigners of the world

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Originally Posted by bobperry View Post
Nothing goes to weather like 40 Vikings on oars.
No, this Greek one points as well (on oars) but it is way faster:



Of course a quinquereme is even faster. I would like to see a replica of one of those. If this one with three rows was already difficult imagine one with 5 rows of remes (oars). They had 300 men at the oars....but that is nothing compared with a Tessarakontere. That means 40 and probably was the biggest men powered boat ever built. It had four hundred sailors, just for the sails, and four thousand rowers. It was a warship and it carried more three thousand soldiers.

Well, it seems that regarding this one they went too far and the ship was difficult to move

And since we are talking about warships, enjoy a favorite documentary among what was the more important naval battle with rowing boats: Salamina. If the winners were not the Greeks today's world would be very different.



regards

Paulo
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Old 11-29-2013
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Re: Open letter to yachtdesigners of the world

[/QUOTE][/QUOTE]

about the ship art of the bayeux tapestry, it should be noted that the tapestry is an example of early medieval representational art. it was an early attempt at 'realistic'' art, which includes foreshadowing. the quality of such art, at the time, was very poor. much like MS I.33, which often shows hands on backwards, the art of the tapestry shows a lack of understanding of the techniques that show perspective. if you look at the art that you posted, you will note that it is supposed to depict ships running before the wind, which 'shortens' the appearance of the width of the yard because of perspective. thus, if viewed straight on, the yard would appear longer.

secondly, look at the sail, it was this very art that made some speculate that the vikings may have used lateen sails because the artist's attempts to depict perspective in the sail ( seen from the edge of the sail ) reduces the foot of the sail to nearly a point, making it look as if it might be some sort of a three sided sail. furthermore, if you wish to use this art as a realistic indicator of dimensional proportions, the sail, itself must have hung down a few yards below the water line, when there was no wind in it. look how long it is, like a bridal train. this is about the worst period representation of viking ships that you could have found. it is totally unreliable as a gauge of proportions.

now, compare this actual viking age art.



notice that the sail, in each representation, from the crudest to the most intricate, indicates a sail that is longer than it is tall. in fact, in each image, the yard is nearly the length of the ship. for all of this art, from different sources, to depict similar proportions can not be a coincidence. in none of these images, is a tall narrow sail depicted.

beyond the evidence supporting the sail used on the reproduction, from the site i linked to, there is the unarguable performance evidence of replicas built with the usual tall, square sail that is attributed to the vikings ( the unsupported sail shape you are willing to accept as historically accurate ). the sailing performance of these vessels, with even this type of sail, far exceeds what you claim could have been possible.

note that, in the following video, depicting smaller versions of longships being tested for the qualities of various hull and sail variations, that the yards are all, to some extent, angled down in the front, much like a dipping lug, when sailing to wind. we know that lug sails can sail efficiently to wind. notice the tight luff on these sails; nothing like the loose luffs you often see in the tall ships of later periods. the way the vikings set their sails, including the use of the beitas, gave them much better control over sail shape.




watching that video, it is interesting to note that the sailing qualities demonstrated by these boats is not at all primitive or crude.

this next video shows the beitas, up close, and shows how the vessel was tacked. you get a really good view of the sail shape. the sail, on this boat, was woven using techniques evident from sail fragments that have been found. it still has the tall, narrow shape because only fragments of sail have been found; nothing to indicate actual shape. good informational video. pay attention to the steering oar. i will mention that later.


http://www.provector.dk/showsingle.a...d=14066&iid=12 i apologize for the link instead of the video. despite my best attempts, i can't get this video to post like the others. it's worth the effort, to watch, though.


this next video shows, again, the beitas and the control over sail shape that was achieved using viking age methods, even with the tall, square sail. at one point, while it is sailing, you can clearly see the flag, which is blowing in the apparent wind. it is obvious that it is sailing close hauled and not on a reach.




this last video clearly shows the ship sailing close hauled. at 4:22, look at the wind vane on the prow. it is clearly indicating that the boat is not on a reach, but is close hauled.





now, compare the angle of sail trim to a 'modern' square rigger.




at 1:00 in the video, you see the ship sailing 'close hauled'. note that the square sails are not trimmed in nearly as tight as on the viking ships, showing that the vessel is not pointing as high. it can't because the sail shape is not as controlled as on the norse ships, which also have hulls that are far more efficient, on the wind.


finally, the under water 'foils'. it should be noted that the viking keel is not straight from stem to stern, as many think. it is deeper in the middle and is shallower at the ends, to help in turning.

also, although they knew nothing about lift, they carved their steering oars in a foil shape. what's more, they understood enough to know that the steering oar being off center would effect the handling, so the foil shape, of the 'rudder' is asymmetrical, to account for this.

the viking ships were far more sophisticated than most people believe, and had/have far greater performance than modern sailors will be comfortable to admit. already, replicas have circumnavigated the globe numerous times and the seafaring accomplishments of the vikings wouldn't be equaled for a few hundred years. the first european born on this continent was Norwegian, hundreds of years before columbus set sail.

if you look on any sailing blog, you will see someone who wants to bash the sailing qualities of these boats. i have seen it a lot; not just in this thread. it must be remembered that much of what the general public 'knows' about the people and technology from these earlier times is wrong; little more than urban myth, much like the idea that vikings wore horned helmets and crude animal furs or the idea that their swords were heavy, poor quality bashing weapons.

if you mention the weatherly quallities of viking age vessels, you often get jokes about '40 vikings rowing up wind'. however, viking war ships, which often had 80 men or more, didn't use their oars due to lack of windward ability. they used them for stealth. a big sail is very visible when you are doing a quick surprise raid. during such activities, the sail and mast would be lowered and they would row in to shore. in comparison, the knarrs/knorrs that were the work horses of the viking age, boats that were used to cross oceans, had only 4 oars even though these were not small vessels. they didn't row up wind. they sailed up wind. the oars were only for moving around the dock. such vessels were lightly manned and had no use for stealth, so they didn't need a lot of oars.

Last edited by captain jack; 11-29-2013 at 02:26 AM.
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Old 11-29-2013
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Re: Open letter to yachtdesigners of the world

I find your analysis of Viking design interesting C. Jack. I would be wary of extrapolating too much from Viking ship burials. They could of been built with the sole intention of the ritual (a form of ritual that dates to the Iron Age) so might not have the attributes of working ships. I would also be somewhat wary of the comparison to the tapestry, as Paulo pointed out, the ships were Norman, the conquest by Rollo took place over 150 years previously and they were thought to be quickly assimilated into the local culture.

What you point out as the crude design of the tapestry could actually have symbolic meaning we know nothing about. The intention of the tapestry was to illustrate a story to the illiterate masses like the stain glass found in churches later.

The 'Dark Ages' might not be as dark as you mention. Viking runic inscriptions are a derivative of Latin text. The Viking Age ring forts found in Denmark used a measurement system derived from the Romans. The danevirke could be a variant of Hadrian's/Antonine walls. The motte and bailey system used by the Normans during the conquest appears to be a form of a Roman marching camp. So I think the Dark Age is a misnomer due to the production of goods was greatly curtailed due to the general lack of a large centralised government (Rome).

Given your interest I would suggest you visit Roskilde where they found Viking Age ships used to block up a portion of the Fjord and now are in a museum. They also have a large shop building replica ships using the tools of the time.

Last edited by ScottUK; 11-29-2013 at 03:51 AM.
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Re: Open letter to yachtdesigners of the world

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Originally Posted by ScottUK View Post
I find your analysis of Viking design interesting C. Jack. I would be wary of extrapolating too much from Viking ship burials. They could of been built with the sole intention of the ritual (a form of ritual that dates to the Iron Age) so might not have the attributes of working ships. I would also be somewhat wary of the comparison to the tapestry, as Paulo pointed out, the ships were Norman, the conquest by Rollo took place over 150 years previously and they were thought to be quickly assimilated into the local culture.

What you point out as the crude design of the tapestry could actually have symbolic meaning we know nothing about. The intention of the tapestry was to illustrate a story to the illiterate masses like the stain glass found in churches later.

The 'Dark Ages' might not be as dark as you mention. Viking runic inscriptions are a derivative of Latin text. The Viking Age ring forts found in Denmark used a measurement system derived from the Romans. The danevirke could be a variant of Hadrian's/Antonine walls. The motte and bailey system used by the Normans during the conquest appears to be a form of a Roman marching camp. So I think the Dark Age is a misnomer due to the production of goods was greatly curtailed due to the general lack of a large centralised government (Rome).

Given your interest I would suggest you visit Roskilde where they found Viking Age ships used to block up a portion of the Fjord and now are in a museum. They also have a large shop building replica ships using the tools of the time.
man, would i absolutely loe to get the chance to do that! if i do get the chance, you can believe i will. that's for sure. the ship meseaum in Norway, as well. it's interresting you mention the vessels sunk near there. Ottar, from one of the videos, is a replica of Skuldelev1. anyhow, that would be the trip of a lifetime, for me.
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Re: Open letter to yachtdesigners of the world

Yeah the Viking Ship Muesum is good too because because one of the ships was a burial so it includes most of the grave goods and is fairly intact. At least the Oseberg ship is. There is a good folk muesum nearby and they relocated a lot of older building from around the country near the muesum including a stave kirk.

You mentioned the Sutton Hoo ship burial though as I recall the only remnants of the boat were discoloured soil and the nails outlining the approximate form. The collection from the excavation is located at the BM in London and is not to be missed.

Kenneth Clark did a series on art for the BBC years ago and as I recall he spoke about the Viking ships near Oslo. Here is a link to the episode. You might want to give the entire series a go.

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Re: Open letter to yachtdesigners of the world

Quote:
Originally Posted by captain jack View Post
....

note that, in the following video, depicting smaller versions of longships being tested for the qualities of various hull and sail variations, that the yards are all, to some extent, angled down in the front, much like a dipping lug, when sailing to wind. we know that lug sails can sail efficiently to wind. notice the tight luff on these sails; nothing like the loose luffs you often see in the tall ships of later periods. the way the vikings set their sails, including the use of the beitas, gave them much better control over sail shape.




watching that video, it is interesting to note that the sailing qualities demonstrated by these boats is not at all primitive or crude.

this next video shows the beitas, up close, and shows how the vessel was tacked. you get a really good view of the sail shape. the sail, on this boat, was woven using techniques evident from sail fragments that have been found. it still has the tall, narrow shape because only fragments of sail have been found; nothing to indicate actual shape. good informational video. pay attention to the steering oar. i will mention that later.


http://www.provector.dk/showsingle.a...d=14066&iid=12 i apologize for the link instead of the video. despite my best attempts, i can't get this video to post like the others. it's worth the effort, to watch, though.


this next video shows, again, the beitas and the control over sail shape that was achieved using viking age methods, even with the tall, square sail. at one point, while it is sailing, you can clearly see the flag, which is blowing in the apparent wind. it is obvious that it is sailing close hauled and not on a reach.




this last video clearly shows the ship sailing close hauled. at 4:22, look at the wind vane on the prow. it is clearly indicating that the boat is not on a reach, but is close hauled.



....
....
the viking ships were far more sophisticated than most people believe, and had/have far greater performance than modern sailors will be comfortable to admit. ....

if you look on any sailing blog, you will see someone who wants to bash the sailing qualities of these boats. i have seen it a lot; not just in this thread. it must be remembered that much of what the general public 'knows' about the people and technology from these earlier times is wrong; little more than urban myth, much like the idea that vikings wore horned helmets and crude animal furs or the idea that their swords were heavy, poor quality bashing weapons.

if you mention the weatherly quallities of viking age vessels, you often get jokes about '40 vikings rowing up wind'. ....
No, you only hear that kind of jokes about an extraordinary wind pointing ability with oars, at least coming from a NA that knows rigs hulls and sails, when you say that a Viking boat with a rig like the ones that you have showed and with baggy linen hand made sails could make 45º to the wind without having such a leeway that would make that angle pointless. We are talking about a useful sailing angle.

If you have a good eye you can see that none of the boats you posted is making 45º to the wind, not even close. I would say 60º or more and they have modern canvas sails, not hand made cloth sails.

Nobody is bashing Vinking boats that were a big achievement for its time particularly in what regards seaworthiness and hull design. It is you that are justifying all types of jokes when keep saying that a Viking boat has the same pointing ability of a modern yacht, with a modern rig since 45º to the wind is the typical performance of a modern cruising sailboat.

Regards

Paulo
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Last edited by PCP; 11-29-2013 at 12:30 PM.
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Re: Open letter to yachtdesigners of the world

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Yeah the Viking Ship Muesum is good too because because one of the ships was a burial so it includes most of the grave goods and is fairly intact. At least the Oseberg ship is. There is a good folk muesum nearby and they relocated a lot of older building from around the country near the muesum including a stave kirk.

You mentioned the Sutton Hoo ship burial though as I recall the only remnants of the boat were discoloured soil and the nails outlining the approximate form. The collection from the excavation is located at the BM in London and is not to be missed.

Kenneth Clark did a series on art for the BBC years ago and as I recall he spoke about the Viking ships near Oslo. Here is a link to the episode. You might want to give the entire series a go.

01 OF 13 - Civilisation: The Skin of Our Teeth (ENTIRE SHOW) - Kenneth Clark BBC TV 1969 - YouTube

thanks for posting the video. definately of interest. you are right about sutton hoo. the soil, at the site, had eaten all of the wood. they wre able to lift the lines of the vessel but the actual depth of the keel remains a mystery. was it as deep as a viking ship or was it just deep enough to be the back bone of the vessel? they can't tell. that's why, when they did a reconstruction ( the sae wylfing ), they opted for just deep enough to be the back bone. they didn't want to jump to conclusions. it still saileds to, i believe, 60 degrees to the wind. been a while since i read about that reconstruction. tey used a sail like waas commonly useds in Roman areas, having no actual sail tro go by. it would be awesome if another, better preserved, anglo-saxon vessel would be found. it wouldn't have to be as rich a find as sutton hoo if the ship was in a better state of preservation. perhaps some day. they discover more, around te world, to advance our knowledge of the past, every year. you just never know what they might find.
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Re: Open letter to yachtdesigners of the world

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No, you only hear that kind of jokes about an extraordinary wind pointing ability with oars, at least coming from a NA that knows rigs hulls and sails, when you say that a Viking boat with a rig like the ones that you have showed and with baggy linen hand made sails could make 45º to the wind without having such a leeway that would make that angle pointless. We are talking about a useful sailing angle.

If you have a good eye you can see that none of the boats you posted is making 45º to the wind, not even close. I would say 60º or more and they have modern canvas sails, not hand made cloth sails.



Regards

Paulo
not linen. actually, the fragments they have found were wool. tightly woven and 'greased' with animal fat, colored with ochre. Ottar originally sailed with woolen sails constructed like the fragments. they were very expensive to make so their replacements were not made that way. however, they discovered that the ochre tightened the weave dramatically and the grease helped to water proof the sail as well as make it more windbreaker-like, in quality. been sailing, all day, and it's chilly out ( 40 degrees as a high ). brain isn't working enough to come up with the words to explain that better. hopefully you get what i mean. anyhow, if you watched the video, you'd notice that Ottar's sail was not baggier than any of the other sails, despite it's hand woven nature. it took as good a shape as the others.

but i've no wish to argue the point. i think the evidence of the reconstructions speak of a better performance than you will allow was possible, especially the sigrid storrada. however, until an intact sail is uncovered and an accurate reconstruction of a real viking sail is made, and tested, the point will remain as conjecture...

much the same as with the sutton hoo ship. sae wylfing is a great reconstruction and is a valuable piece of experimental archaeology, however, until an intact hull, showing the actual keel, is found, it is impossible to say what kind of performance anglo-saxon vessels were capable of, with real certainty. too much remains unknown.

but understanding is advancing. previously, historians believed that the anglo-saxons did not have sail power. on study by people familiar with sailing and longships, however, the fact that the vessel was braced for a steering oar showed that it must have been sailed as none of the smaller, oar only, vessels were designed for a steering board.

there are ground breaking new discoveries, every once in a while, that really open our eyes. at one time, historians claimed that the saga tale of finding north america was just a legend....until they found the remains of the settlement.

it's kind of useless to argue on the basis of certainty, rather than just possibility, with so much yet unknown.

Last edited by captain jack; 11-29-2013 at 05:10 PM.
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Re: Open letter to yachtdesigners of the world

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... at one time, historians claimed that the saga tale of finding north america was just a legend....until they found the remains of the settlement.
...
You have a point there even if after having read Eric's Saga (parts of it) I had no doubt they had been in America, long before those settlements were discovered. It happens the same regarding the northwest passage that was made by a Portuguese pilot 200 years before the "official date" and even if that is documented even more precisely than the discovery of America by Eric, in what concerns the Saga, historians keep doubting it

Regards

Paulo
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Old 11-30-2013
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Re: Open letter to yachtdesigners of the world

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You have a point there even if after having read Eric's Saga (parts of it) I had no doubt they had been in America, long before those settlements were discovered. It happens the same regarding the northwest passage that was made by a Portuguese pilot 200 years before the "official date" and even if that is documented even more precisely than the discovery of America by Eric, in what concerns the Saga, historians keep doubting it

Regards

Paulo
yeah. there is always stuff like that. it's kind of a flaw in 'experts'. it doesn't matter if it's historians, scientists, paleontologists, whatever experts you can name...they want to prove their theories correct. it doesn't matter what the truth is. they want to be right. they are authorities and they seem to think that means they can't admit that they might be wrong.
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