On the Trail of Sail History – the Vikings

We left off somewhere around 1350 BC, when the Mycenaean kings may or may not have been requiring plain linen cloth to be woven as a tax or tribute intended for sail use.  Or possibly for tents or soldiers’ under-armor.  But that is the best information I have so far about early sails.

As we get closer to the present day, there is a little more information.  Here is Julius Caesar in 56 BC, describing the boats of a people called the Veneti, that he was battling off the coast of Brittany:

…anchors are held by iron chain instead of rope. Their sails are of hide or softened leather instead of canvas, possibly because they have no flax, or don’t know how to use it, but more likely because they figure canvas won’t stand up to the violence of ocean storms and the force of the winds there or drive such heavy vessels efficiently.  In a clash with a fleet of these craft the only advantages our boats had were their speed and the fact that they are driven by oars; in every other respect the enemy’s type of ship was better suited and adapted for these waters with their strong winds.  (quoted in Illustrated History of Ships and Boats, by Lionel Casson, 1964, Doubleday and Company.)

I would never have thought of making leather sails!

I don’t know about you, but my respect for Julius Caesar just went up about 100%, because he wasn’t just out there running battles, he understood the details that went into it.  He knew about flax!   I also appreciate that his comparison shows us that the Romans were using linen canvas at this time, and rope to hold their anchors.

So then!  We get to the Vikings!

Viking ship on a picture stone, at the Fornsalen Museum in Gotland. Now I want to know about that diamond pattern in the sail. source

The Vikings used another material I would never have thought of – wool!

Hmmm! you’re thinking.  Wool!  It would be a lot less brittle than linen, more stretchy – so maybe that would help it last better in strong winds…but wouldn’t those same winds just blow right through it?  Can you get wool to be air tight?

It turns out you can, IF you rub a mixture of horse fat (from under the mane, don’t ask me why), water, and ochre into it, followed by some coats of hot liquid beef tallow. This is called smörring. The sail will develop a good draw, and won’t be as likely to rip in a gale the way linen would.  And the ochre is an anti-bacterial which helps keep the sail from rotting.

And how do we know all this?

In the 1060s a settlement called Roskilde, on a little fjord in Denmark, was faced with attack by sea.  They decided to make it harder for anyone to get into the fjord by scuttling three ships, and ten years later, they added two more.

The ships sat there, forgotten, until 1924 when a fisherman brought up a piece.  In 1956 an archaeological survey was done, and it was decided to excavate and preserve the ships.  They are now in the Viking Ship Museum of Roskilde, where they have been studied extensively, reconstructed, and sailed.

When the ships were brought up in the 1950s and 60s, no traces of the sails remained, but the archaeologists knew that the Vikings used woolen sails, from writing and pictures from that time.  Lengths of sail fabric could be used as currency and a means of taxation (just like the theories about sailcloth in the Mycenaean era!)

Also, sometimes the Vikings buried someone important in a whole ship, with all necessary belongings, and  some textile fragments have been found in those.  (For a fascinating look at those, look at this extensive study.) And, a few people still used woolen sails into the 19th century.

In the 1990s, an alert archaeologist heard that while a medieval wooden church was being repaired, old textile fragments had been found.  He investigated it and ten other churches, finding that in one church, woolen material had been found packed between the roof planks.  One piece had a reinforced eyelet for a rope, evidence that it was a sail.  It was carbon-dated to 1280 to 1420, making it the oldest sail fragment found to date.

You can see it on the third page of this article (which is where I got most of this information) and I strongly advise you to go look.  You will not believe how it is woven.  It is made of singles, not plied yarn, and it is woven like very loose burlap.  With the little I know about sailing, I would never imagine this kind of cloth would work at all.

But researchers analyzed those fragments, and reconstructed the sails, and analyzed again, and they did work.  The Viking Ship Museum has put these historically accurate sails on seven of their replica ships and sailed with them.

The ancient sail fabric was made from two different yarns, spun from one primitive hairy breed of sheep.  The warp yarn used the long hair, spun tight with a Z-twist, and the weft yarn was more softly twisted from the hair and short fiber.  That in itself shows lots of knowledge and skill – being able to create different types of yarn for different tasks.

Then these were woven in a 2/1 twill* on an upright warp-weighted loom, with 8-9 warps per centimeter (that’s 40-45 ends per inch)!  There were 4-6 wefts per centimeter (20-30 picks per inch).

If you’re unfamiliar with weaving, let me assure you that that is phenomenal weaving.  Wool is very sticky to work with – I think most modern recommendations for handweaving wool would be about 10-12 warps per inch.

warp-weighted loom

Warp-weighted loom at the National Museum of Iceland – this is the type of loom the sails were woven on. source

When the sails were reconstructed, the researchers could find the right breed of sheep, wild Vilsau sheep, still existing only in Norway.  (And there are no images of Vilsau on the web!  I guess when I am making my visit to Denmark to see the Viking Ship Museum I will have to make a side trip to Norway to find these sheep.)

They had the yarn commercially spun, and used modern horizontal looms, but they still estimated the cost for the sails for one reconstructed ship to be one million Danish crowns, or 2000 British pounds per square meter!  In American money at today’s rates, that about $3,360 per square meter.

Once they had the fabric woven, the researchers did all kinds of tests on it, testing it for tensile strength and ability to absorb bursts of wind.  They used smörring to modify the sails and then tested their efficiency again.  After lots of math, they determined that the woolen sails would likely outperform the hemp and linen sails that were used later.

The article that I drew most of this information from is from 2002 – the Viking Ship Museum has a page full of updated information on woolen sails here.

Of course as I have been reading so much to try to learn about sails, I am also picking up a lot of information about hulls, rudders, masts, and rigging.  And what strikes me the most is how ingenious people can be, how brilliant they are to use the materials around them to accomplish one basic purpose with such a myriad of designs.  When I get interested in some little weird side-road of history, it doesn’t matter what it is, I am always amazed on other people’s creative insights, and that gives my own creativity a little boost.

* Our blue-jean material is woven in a 2/1 twill – the weft goes over two warps and then under one, giving more stretch and flexibility than plain weave, in which the weft goes over one warp, under one.