Tuesday, May 6, 2014

Calculating the draw weight of a Beaker bow (Part 2)

This is the second part of several pieces I'll do on the Beaker bow.

In the first part, I tyrannically cast away all doubt with regards to Beaker wrist-guard functionality.

But we still are not done with wrist-guards...

Broadly speaking, there have been proposed three rough shape classes of wrist-guards associated with Beakers (most recently by Folkens et al, 2008)

This is important because this could yield three major bow-classes used by Beaker archers.  We may be able to infer the size of the bow and the weight of the bow depending on how the bracer was worn.  So I will modify some of the previous classifications from papers dealing with the subject to how I view wear of the wrist-guard and with which bow size & weight is most appropriate.

Radial bone guard #1

This bracer was worn to protect the radial bone on the inside of the weak forearm.  One end is widened to allow for wrist movement, the other end for the increase in forearm. 

2200 - 2000 BC, Kellythorpe Barrow, British Museum

It may suggests that the wearer of the guard fired his bow vertically with a locked wrist, as in the picture below, and not like a longbow.

 The depth of the bow would be a mid-size, vertically-held bow because the right arm draws the string across the upper body and the left radial bone is exposed due to the required midcarpal supination locking required from a heavy bow.  Locking the wrist allows us to project great force with our hands, such as when using tools like a hammer.  Modern compound bows alleviate the force on the locked wrist because the breaking weight in draw is reduced but with the benefit of substantial acceleration on release.  

Fig. 19 (Van der Vaart, 2009)

You can see how the archer draws the bow with his right arm and the left arm and wrist are locked.  The bow used in the picture is probably between 30-40 lbs and may inflict a painful lash, but not a dangerous one for the occasional sport shooter.  

 Modified Fig. 19 (Van der Vaart, 2009)

I added a red circle to the second picture where the radial bone is located and where the radial bracer would need to be placed for a substantially more powerful bow.  A combination of the stone core and the leather outer cuff may have also provided rigidity for higher tension forces on the forearm.

Large Longbow guard #2

By "Longbow" I'm referring bows generally taller than the archer and much more powerful.  (The definition seems to vary)  Given the width of this bracer and where it would need to be placed, I'd suggest that the wearer of this bracer fired his bow in a canted manner, such as many of the larger longbows.

2280 - 2030 BC, from Barnack, British Museum

Simple wrist guard #3

I would guess without knowing actual numbers, that the very vast majority of Beaker bracers fall into this simple group with varying size and quality.  Unlike the two cuffed versions above, this one was probably worn exactly like Jayne's wonderful illustration of the Amesbury Archer below:

"Amesbury Archer" thanks to Jane Brayne

The coloration of these Class #3 wrist-guards seems to have had some special significance.  Some natural red or greens were sought out and transported widely (1) and some were colored red with ocher in slate Dutch examples (3).


The Bracer's tell us very broadly about three major types of Beaker bows.  We can tell from the bracer how each bow was held and with the robustness of the bracer, have a general idea of the size of the bow it supported.


(Fokkens, Achterkamp, Kuijpers, 2008) "Bracers or Bracelets? About the Functionality and Meaning of Bell Beaker Wrist-guard"

Smith, Jonathan (2006) "Early Bronze Age Stone Wrist-Guards in Britain: archer's bracer or social symbol?"

Van der Vaart, Saaja (May 2009)  "Bell Beaker Wrist Guards Reconsidered:  A Research into their Functionality and Possible Uses"

*When yew is cut right, it makes a natural composite with inner heart and outer sapwood forming the 'perfect bow'.  So its hard to imagine any kind of composite laminating being required at any point in European bow history.

**Google 'Mary Rose archers' and you'll find reference to an on-going study on the skeletal adaptations and large forearms of heavy medieval archers.


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    Wrist and Forearm Splint Right-Left

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