Crab Bow Measurements

[Bede]

These are the measurements I have taken of a crab bow. The measurements are read directly off a digital micrometer. The paint surface was largely intact. I have included the measurements of one limb. The limbs were symmetrical and of equal length. There were minor discrepancies due to sinew bindings below the nocks.



This is under construction while I try and get the Table with the measurements to format correctly. I will add some pictures and sectional profiles as well.

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Inches		
Distance from Nock	        Width	Thickness
-0.5	                     0.362	0.467
0	                        0.509	0.551
1	                        0.515	0.580
2	                        0.604	0.642
3                        	1.184	0.662
4	                        1.306	0.666
5	                        1.383	0.701
6	                        1.440	0.727
7	                        1.475	0.770
8	                        1.519	0.821
9	                        1.530	0.753
10                          1.576	0.589
11                          1.591	0.560
12                          1.594	0.519
13                          1.600	0.494
14                          1.606	0.475
15	                       1.599	0.469
16	                       1.592	0.444
17	                       1.580	0.428
18	                       1.547	0.441
19	                       1.482	0.488
20	                       1.366	0.518
21	                       1.184	0.611
22	                       0.927	0.807
23	                       0.758	1.027
24                          0.867	1.148
		
		
Width of tip insert              0.140	
Nock depth	                    0.195	
Nock internal width	           0.164	
Base of nock to tip	           0.912
Total length  nock to to nock       48.0
Total length tip to tip             49.824
                             	

[Bede]

This a view of the bow from the side.

[Bede]

The grip. Please note that there are no external bindings. They are usually repairs, not normal additions to the bow. Tips have fine sinew reinforcements under the decoration. This is known from some Turkish bows as well.

The bow is decorated and has fine sinew covering both the belly and the back of the bow. From a damaged part of the bow, it appears that the sinew is first laid on longitudinally and then an extremely fine sinew is wrapped around the limbs from one end to another before the paint was applied. However, this might be an illusion caused by the the first layer of sinew being roughened tangentially.

[Redhorse]

Thanks, the best crabbow blueprint I have seen.
It's thinnest at the working area close to handle, can you see if the sinew, wood or horn is thinner?

[Dusan]

Thanks Bede. Very helpfull information.

[PjSingh]

Thank you Bede,This more than helps out,I have been looking forward to these measurements for a long time.I have just finished a bit of research in to the pigments used for these bows and the methods of how these were applied,I will post them here soon for everyone.
Thanks
P.J.

[Jos?Dom]

Thank you for the info and pictures. I don?t know much about these bows, known as crab bows, North Indian bows, Mughal bows or sometimes Lahore bows. So I?d like to ask some questions:

1) These bows are always covered with sinew over the horn on the belly? Are there more alternatives?
2) Those 3 crossed lines on the grip section seem to be present on most samples I have seen through pictures. I wonder if these are leather bands glued? is this just a decoration?
3) We have an idea about corresponding draw lengths to each type of bow. For example Turkish bows were known for short draw (in the 28-29" draw) and Chinese Manchu bows have a long draw (maybe from 34 to 36"). The crab bows are designed for something in the middle?
4) They seem to be inspired by the Turkish bows, except the abrupt transition from sal to kassan and straight tips. How would you compare these bows with the Turkish counterparts? maybe the same or inferior weapon in terms of performance and stability.
5) What about the material used for covering the back, leather, barl or just painted sinew?

[Bede]

I will try to answer as many questions as I can.

1. 1. All bows of this type that I have seen that are in good condition have sinew covered bellies. Adam in an article points out that the sinew is applied longitudinally. The bow in the picture has a damaged section on the bending part of the limb. I could see the sinew fibres running lengthways. I thought I could see a very fine layer of transverse sinew, but it may have been an optical illusion caused by residual brush strokes.
   2. The three bands are either the edges of leather or bark strips or sometimes strings applied under the surface. They may have been a standard way of joining the pieces or the normal way to mark the centre of the bow.
   3. Arrows associated with crab bows are always in the 27-29 inch range. The relationship to Turkish draw lengths is obvious. Mughal paintings often show draw lengths similar to the Turkish.
   4. I have not shot an old bow or a modern reproduction of horn-sinew-wood so I have to go on reports from people who have. These bows are probably older in design than Turkish bows. There are some parallels with mediaeval bows in Central Asia and North China into the Ming Dynasty. McEwen told me that well made crab bows performed like Turkish bows. He said that they were very stable because of the relative width of the bending section of the limbs. He was not referring to flight bows. They came in various qualities and the good ones performed well and the poor ones were sluggish.
   5. Adam, in his article described various processes. Sometimes there was a layer of silver foil under the paint as a moisture seal. I have seen ones with both thin bark under the paint and others with thin leather. Two I have appear to only have paint.

I will have more details from another bow I have X-Rayed and information on the horn soon.

[Jos?Dom]

Thanks, that's valuable information.
Here's another sample of this style of grip:

[Andrew Hall]

Bede

Thanks for the measurements and photos.

The raised lines in the grip could have been used to get a more consistent hand position. Assuming that they were not just decorative - they often seem to be incorporated into the decoration.

I have seen a semi-dismantled crab bow that appeared to have had some sinew wrap around the sharp bend of the limb/siyah transition. The Society of Archer-Antiquaries Museum contains a Sind bow in poor condition that definitely had a short section of wrapping at a similar point. Strangely, the bulk of the sinew backing was on top of the wrap on the Sind bow, so the wrapping would have had no effect at stopping the backing pulling away from the limb as it dried.

I wish more information was available on the links between the bone-reinforced early medieval bows and the Turkish, crab and other later designs. Unfortunately as most of the earlier archaeological evidence is based on bone plates alone, the evidence stops as the plates fall out of use.

Figure 423 in Nicole, Arms and Armour of the Crusading Era 1050-1350: Islam, Eastern Europe and Asia, Greenhill Books, 1999 shows a line drawing of three bows of Turkish looking shape found in a collapsed room in upper Mesopatamia, one of which was carbon dated to 1195. So the Turkish design may be quite early.

Andrew

[Bede]

Andrew,
You and I both know that someone cannot get a precise date from Carbon 14 that is accurate down to a year at 1,000 years into the past. Dr Nicolle sometimes includes information of more precision than is technically possible. In more recent works, particularly about the Tibetan material in the Metropolitan Museum Art in New York, spreads of several hundred years are given for more recent material.

I too have seen bows with various types of bindings at weak points. Sometimes they were sinew and other times crude rawhide. In Korea, highly reflexed bows are often repaired by bindings. In some cases they are bound before any issues have appeared. In modern Mongolian bows, nylon bindings can be applied at the end of the manufacture. Your description of the Sind bow is unusual even in this context, but Sind bows are the ones with the most points of failure. One of the Sind bow shaped Afghan bows in the Grayson Collection has two iron rivets through the hand to prevent the horn lifting.

Getting back to the other point of your post, the origins and relationships of the various "modern" composite bows, I have found crab bows as very interesting. Firstly, the lack of reflex between the kasan equivalent and the bash equivalent combined with the strong reflex at the kasan to sal boundary initially suggests a connection with early non-contact siyah design.

However, the internal construction of the crab bow is much more complex and clearly not in a direct line of descent. The X-Ray images I have and the dissected bow I examined at the Koppedrayers' house show that the ear section is nearly rectangular for most of its length and the ridge is mostly sinew with a tiny wooden spine contributed by the core. The Koppedrayer bow had the splice for the siyah was in the last section of the bending part of the limb before the change in angle. The thin horn on the belly did not even reach the angle and just covered the splice. This core shape has more in common with the bows excavated in China with birchbark coverings. In these bows the triangular section of the kasan has not yet developed.

It looks to me that horn on the bow I illustrated here was not as wide as the limb. This is consistent with the Koppedrayer bow which had a horn strip almost a third of the width of the limb. In a communication from Edward McEwen, I was informed that many crab bows had the horn wrap around the curve of the angle between the siyah and the bending section of the bow. It did not continue much up the siyah from that point.

The construction of the cross-section of the Koppedrayer bow at the bend had the belly built out with sinew. The published cross-sections in The Grey Goose Wing show much more wood in the siyahs which I think would be more efficient in limb mass. Sinew is heavier than wood. It makes me think that the bowyers in one case were trying to make their bows look like the more efficient type by building out the belly.

On the back, building the kasan up with a ridge of sinew would be an efficient way of stiffening it without changing the core. It seems to me that the Turkish and Persian solution of shaping the core into a stronger triangular section is a more advanced development by way of reducing the mass while still achieving the required stiffness.

The question then becomes, did the crab bow come first and represent the transition between rectangular kasans and triangular ones or is the ridge on these bows a retro-fitting by adding sinew to copy the ridges on other bows.

Many Sind bows have sinew ridges on the back of the bending part of the bow which take much of the tensile load. This may be an old tradition lost elsewhere or it could be an innovation to improve performance. Either way, it shows that Indian bowyers were masters of many techniques and were capable of complex design.

I am trying to find a way to scan my X-Ray images. I will post them here if I succeed. Otherwise you will only get drawings.

[jack farrell]

Nice bow Jose. Where did the pic come from? Is that a gem type thumb ring? Yokhua told me he thinks the thread decoration on the grip is a stylized representation of a remnant lashing to help keep the horn down. Makes some sense.

Then what about the nock tips? I see some of them are solid horn.

[Jos?Dom]

Sorry, I didn't mention the source. Here it is:

http://www.jfsantiquearms.com/stephens_ ... on/o4.html

[jkekoni]

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          DIST /cm         Width      Thick
                 -1,27       0,92       1,19
                     0       1,29        1,4
                  2,54       1,31       1,47
                  5,08       1,53       1,63
                  7,62       3,01       1,68
                 10,16       3,32       1,69
                  12,7       3,51       1,78
                 15,24       3,66       1,85
                 17,78       3,75       1,96
                 20,32       3,86       2,09
                 22,86       3,89       1,91

                  25,4          4        1,5
                 27,94       4,04       1,42
                 30,48       4,05       1,32
                 33,02       4,06       1,25
                 35,56       4,08       1,21
                  38,1       4,06       1,19
                 40,64       4,04       1,13
                 43,18       4,01       1,09
                 45,72       3,93       1,12
                 48,26       3,76       1,24
                  50,8       3,47       1,32
                 53,34       3,01       1,55

                 55,88       2,35       2,05
                 58,42       1,93       2,61
                 60,96        2,2       2,92
                                 
                                 
Width of ti                  0,36
Nock depth                    0,5
Nock intern                  0,42
Base of noc                  2,32
Total lengt                121,92
Total lengt                126,55

[Bede]

A close examination of one of the X-Rays I have of the grip of one of my crab bows shows a very fine line that appears to be part of a V-splice. The published diagram of a Persian bow that was in Turkish Archery and the Composite Bow had the grip section applied like a riser on the back of the centre of the bow. In the belief that there was a strong relationship between the later bows used in Persia and the late bows in India, I had thought this easy method of construction would have been used there (India) too. After all, the Manchus and the Koreans used this system. However, the X-Ray looks different and, taking into account the wider limbs of the crab bow, the position and size of the splice is very similar to Turkish bows.

The crab bow seems to have much thinner wood and horn sections than other composite bows of similar lengths. This is obviously a necessity when you consider how little of the bow limbs bend.

Regarding the lines on the grip, string-under-leather decoration is very common in Turkish and Persian sword scabbards. The wooden cores of the scabbards are decorated with string laid in patterns on glue and then wet leather was glued over it and pressed into the designs. Considering the grip area is much more stable than the transition between the grip and the bending limb, there is little need for a strengthening binding. It would be useful for locating the hand and centring a cloth cover for the handle. Swords often had wrappings on the grips made from silver bullion tape that prevented the hand slipping due to sweat (or blood). The tapes could be unwrapped and washed or replaced when they became dirty. I have seen pictures of composite bows with the handles wrapped in the same way. I don't know if this was common, but many grips show no sign of wear.