More on non-metallic armour

[Erpingham]

By a mysterious mixing of current archery and armour research and Justin's plastic armour spoof, I came across some tests of the effectiveness of ancient linen armour.  Now, the method of making the armour is controversial - it involves making linen reinforced glue sheets of up to 27 layers of linen and forming them into armour.  But it was found that it created armour that would protect a historian from another historian with a bow at 10 feet .  The connection to plastic armour is that the method they used was essentially that used in fibre reinforced plastics using ancient materials.

My interest was actually in a brief comment they made about non-glued layered linen armour, saying it was much weaker.  Non-glued sewn layered armour is what they used in the Middle Ages, which was my interest.  Unfortunately, the preliminary report I found online mainly concentrates on the glued linen, only mentioning their experiments with sewn layers.  I wonder if anyone has made a sewn-layer linothorax? 

Anyway, I shall return to my reading on medieval non-metalic armour (findings so far suggest that a historian wearing it should beware of other historians with longbows at much greater ranges).  If anyone else is interested, this article has some useful info.

[Duncan Head]

That first report is by Aldrete et al., the authors of the Linothorax book. The book also concentrates on the glued linen solution, but they do mention experiments using armour with the layers stitched - shooting arrows at a patch of textile armour rather than making a whole stitched cuirass - and my memory was that the results were not all that much different from the glued version. It was the stuffed and quilted "patch" that  was the weakest.

Mike Loades in the Composite Bow section of the Osprey Warbows compilation, which I was reading last night, describes the construction of a Muslim Near Eastern kazaghand armour based IIRC on a description by David Nicolle. The leather plates are coated in several layers of glue or varnish into which sand or grit has been mixed - so you've got a complex defence of multiple materials, including stone! Non-metallic armours are, clearly, not always simple or low-tech solutions.

[Erpingham]

my memory was that the results were not all that much different from the glued version. It was the stuffed and quilted "patch" that  was the weakest.

The article does say

Laminated test patches possessed about 15 % more resistance to penetration than sewn ones, while quilted patches were ineffective.

which is probably good enough for my purposes, though doubtless they recorded more detail.  I haven't found much on tests on "stuffed" armours (like the pourpoint and the jack) but I suspect that the density of stuffing would matter quite a bit.

Incidentally, to go with the description of Cuchulain's layered armour given in Jones' article, I also tracked this down, as an example of complex composite armour

Then rose the royal chief  of the fiana of Ireland and Scotland
and of the Saxons and Britons, of Lewis and Norway and of the
hither islands(Finn Mac Cumhall), and put on his battle-dress of combat and contest, even
a thin, silken shirt of wonderful, choice satin of the fair-cultivated
Land of Promise over the face of his white skin ; and outside over
that he put his twenty-four waxed, stout shirts of cotton, firm as a
board, about him, and on the top of those he put his beautiful, plaited,
three-meshed coat of mail of cold refined iron, and around his neck
his graven gold-bordered breastplate, and about his waist he put a stout
corslet with a decorated, firm belt with gruesome images of dragons,
so that it reached from the thick of his thighs to his arm-pit, whence
spears and blades would rebound.

This would seem like an upmarket 13th/14th century Irish armour, with mail over layered "cotton" (or linen?).  The breastplate would then then be a pisane but the leather corslet is interesting (Cuchulain has one as well).  Anyway, an example of the use of non-metallic armours in a composite "battle-dress".  And, yes, I could have gone with a knightly armour of mail over gambeson but where would be the fun in that? 

[PMBardunias]

That first report is by Aldrete et al., the authors of the Linothorax book. The book also concentrates on the glued linen solution, but they do mention experiments using armour with the layers stitched - shooting arrows at a patch of textile armour rather than making a whole stitched cuirass - and my memory was that the results were not all that much different from the glued version. It was the stuffed and quilted "patch" that  was the weakest.

Mike Loades in the Composite Bow section of the Osprey Warbows compilation, which I was reading last night, describes the construction of a Muslim Near Eastern kazaghand armour based IIRC on a description by David Nicolle. The leather plates are coated in several layers of glue or varnish into which sand or grit has been mixed - so you've got a complex defence of multiple materials, including stone! Non-metallic armours are, clearly, not always simple or low-tech solutions.

A substantial amount of Aldrete's book drew directly from a RAT thread I was on back in the day. He was very selective in his use of evidence, and some of his "pro" evidence is sketchy (I know because I first suggested mummies and masks).  If you are interested I wrote an article which was really a summary of that RAT discussion for AW back when Aldrete's book came out and we were all a bit miffed.  The article's title was "Don't get stuck on glued linen."  You can read the text here: http://hollow-lakedaimon.blogspot.com/2018/07/the-linothorax.html

[Erpingham]

Thanks for that Paul.  It did occur to me while reading it that the Greeks could have "pipe-clayed" their armour to keep it white.  Pipeclay is essentially kaolin, gum (or glue) and water.

My main interest, as you know, is in the arrow-resisting capabilities.  I found the experiments in the paper (and elsewhere) suggesting that Greek armour was essentially proof against contemporary archery virtually to spear-fighting distance.  Does this fit with your experiments?

[PMBardunias]

Thanks for that Paul.  It did occur to me while reading it that the Greeks could have "pipe-clayed" their armour to keep it white.  Pipeclay is essentially kaolin, gum (or glue) and water.

My main interest, as you know, is in the arrow-resisting capabilities.  I found the experiments in the paper (and elsewhere) suggesting that Greek armour was essentially proof against contemporary archery virtually to spear-fighting distance.  Does this fit with your experiments?

If the archer is using a bow of 45lbs or less and evidently really crappy arrowheads.  With a 60lb bow, you die, the girl dies, everybody dies, and Persians surely shot heavier than 60lbs. Below are the tables from his book.

See also attached, what should have ended the notion of glued linen as leading contender for material.  As a scientist, there are certain things we are beaten into us like religious tenents. One is that you cannot call something different unless it has some measure of statistical significance.  There is no difference between glued linen and simply layers of linen stitched together. Once he acknowledged that the discussion turned to focus on how glue might be easier to make than sewn layers, one anyone here would think highly unlikely I am sure.

They could surely have pipe clayed the armor, but that does not add significant protection. If you make it thick, it spalls off. Of course the craftsman who is making either pipe claying or working kaolin into the linen could easily discovered the other process, and pipe claying the outer layer could have been a means of waterproofing.

[Erpingham]

Thanks Paul.  I must admit, I'm not seeing a consistent 15% advantage of laminate over sewn there.  Did they do a statistical analysis?

I assume the duelling historians shot each other with a 25lb bow and the worst arrow.  Also, though eye catching for news broadcasts, perhaps a bit misleading on the effectiveness of the armour in combat - a more realistically powerful bow would have produced 40mm plus penetrations with numerous arrows at 7.5m or further.

It does show what the Jones study also shows - performance is very arrow dependent.

On sewn v. glued and ease thereof, I would note that, when medieval people came to make similar armour, they chose to use a sewn technique, even though they had the animal glue technology.  While making things with a sewn technique is labour intensive (although I don't know of any studies on gambeson-making, there is a time log for making a pourpoint, which shows it is very long task), it isn't technically that difficult. 

[PMBardunias]

Thanks Paul.  I must admit, I'm not seeing a consistent 15% advantage of laminate over sewn there.  Did they do a statistical analysis?

I assume the duelling historians shot each other with a 25lb bow and the worst arrow.  Also, though eye catching for news broadcasts, perhaps a bit misleading on the effectiveness of the armour in combat - a more realistically powerful bow would have produced 40mm plus penetrations with numerous arrows at 7.5m or further.

It does show what the Jones study also shows - performance is very arrow dependent.

On sewn v. glued and ease thereof, I would note that, when medieval people came to make similar armour, they chose to use a sewn technique, even though they had the animal glue technology.  While making things with a sewn technique is labour intensive (although I don't know of any studies on gambeson-making, there is a time log for making a pourpoint, which shows it is very long task), it isn't technically that difficult.

yes, there is no significant advantage, that 15% is wishful thinking. There are too many variables in this experiment to make it standardized enough to find significance without a very tight distribution for each armor type. Was the bow pulled back exactly the same each time, did the arrow hit at exactly the same angle each time, etc.  It is best to just stick to a qualitative assessment in a study like this. I used No, Whole, and Partial pentration when shooting at linen patches.  Getting into mm of penetration without controls is hazardous unless you show me the variance within each test.

The elephant in the room with his book is a technique that I was one of the first to bring up for the T-Y based on an Etruscan find, but has since been very well presented beyond anything I could do. Essentially it is heavy linen fabric made by a twining process. We do not commonly use this today other than in making rugs or mats. This is the technique used to make the linen undergreave or greave from Dura Europis.  Gleba has a great paper on this, and it is to my mind the only technique that makes sense of the 2-ply and 3-ply corselets we read of.  It can be woven very thick, and if you want multiple layers, you can weave them together directly.  I have come to believe that the linen T-Y was woven whole to form. Probably the tube and first layer of pteruges, then the yoke and second layer added, but the layers could have been woven together directly.


Watch the questions at the end of this: https://www.youtube.com/watch?v=SLBMupbqo2I

[Erpingham]

It is best to just stick to a qualitative assessment in a study like this. I used No, Whole, and Partial pentration when shooting at linen patches.  Getting into mm of penetration without controls is hazardous unless you show me the variance within each test.

Good scientist as you are, I'm sure you minimise variables within your control (like standard target, shot distance) to back up your qualititative assessment.  I would also expect you have definitions of "whole" and "partial" penetration?  I find there is a useful simplicity in modern armour standards defining success or failure as to whether a defined depth of penetration has occurred.

[PMBardunias]

It is best to just stick to a qualitative assessment in a study like this. I used No, Whole, and Partial pentration when shooting at linen patches.  Getting into mm of penetration without controls is hazardous unless you show me the variance within each test.

Good scientist as you are, I'm sure you minimise variables within your control (like standard target, shot distance) to back up your qualititative assessment.  I would also expect you have definitions of "whole" and "partial" penetration?  I find there is a useful simplicity in modern armour standards defining success or failure as to whether a defined depth of penetration has occurred.

Yes, I kept to one arrowhead, the modern razor broadhead that caused Aldrete so much trouble, and one distance- point blank, 2m, so as to minimize arrow drop.  But more importantly, I did not pretend it was a scientific study , but more a demonstration to show that Kaolin added protection.  In fact, Aldrete could have lost his position for firing those arrows at a human. The level of pre-screening and oversight that you have to go through to do any sort of "experiment" on a human when employed by a university is daunting.

My definitons by the way were, no point showing through the material, the arrowhead showing, but the blades not through the material, and the blades through the material.  In general, depth of penetration is less useful than you might think if we do not know the angle of impact. At some point I may do an experiement, but we have protocols for this, none of which involve bows and arrows, but controlled penetrations as in the paper Patrick posted. The converse of course is that knowing what an arrow does under controlled conditions does not automatically correspond to real settings.

[Erpingham]

Even the standardised tests on stab vests allow variation between different impacts using the same test set up.

Then you get the significance of various penetration depths.  Aldrete and co. seemed to attach significance to 40mm, from the highlights in the table.  By contrast, the latest British stab vest rules allow no more than 9mm penetration as "safe". 

[PMBardunias]

Even the standardised tests on stab vests allow variation between different impacts using the same test set up.

Then you get the significance of various penetration depths.  Aldrete and co. seemed to attach significance to 40mm, from the highlights in the table.  By contrast, the latest British stab vest rules allow no more than 9mm penetration as "safe".

Somehwere I have a paper on the actual depths of organs as determined by ultrasound. Major organs like the liver are very shallow. 

[Erpingham]

Even the standardised tests on stab vests allow variation between different impacts using the same test set up.

Then you get the significance of various penetration depths.  Aldrete and co. seemed to attach significance to 40mm, from the highlights in the table.  By contrast, the latest British stab vest rules allow no more than 9mm penetration as "safe".

Somehwere I have a paper on the actual depths of organs as determined by ultrasound. Major organs like the liver are very shallow.

To quote the abstract of one of the papers used for the stab vest standards
Connor, S.E.J., Bleetman, Anthony & J Duddy, M : Safety standards for stab-resistant body armour: A computer tomographic assessment of organ to skin distances (1998)

The minimum distance from the skin to the vital organs was measured. No organ would have been breached at 5 mm of knife penetration deep to body armour. 41% of pleurae, 61% of livers, 64% of femoral arteries, 25% of spleens and 6% of hearts would have been breached at a depth of 20 mm of knife penetration.

Aldrete etc. used this study

Anthony Bleetman & Jules Dyer : Ultrasound assessment of the vulnerability of the internal organs to stabbing: determining safety standards for stab-resistant body armour (2000)

to determine that the "safe" penetration from the front of the armour is 45mm (p.115).  This allows a rear face penetration of 18mm.  Note they have gone for an "average" depth before striking a major organ.  The originally quoted study gave the minimum depth of a major organ (a liver) as 9mm (which explains the Police standard).  Given the 61% of livers within 20mm of the surface in the first study, Aldrete et al are perhaps insufficiently conservative with their 18mm.