Its possible to make nocks that will hold a string on so that the string angle can exceed 90 degrees, and there are bows made in the Arctic with flaring or T-shaped nocks that were probably designed for just that purpose, but the Tuktut Nogait bow didn't appear to have that style of string nock.For the bow string, I made a 2 ply cord of twisted sinew. The sinew fibres are separated into very fine silky threads that are twisted together while wet into a thread that is about 1/8th of an inch thick. This thread is made a little over twice as long as the finished string needs to be. I let that thread dry over night and then looped it in the middle and twisted it into a simple two ply cord. While that was drying I twisted the two ends together to create a second loop at the opposite end of the cord and let it dry under tension.
To add tension to the cord backing of the bow a sinew twister is used. The antler sinew twister is slid through the middle of the cord bundle and used as a wrench to twist the cord into a cable. To hold tension in the cable, I tied a leather lashing through the middle of the cable around the handle of the bow before removing the sinew twister. While the bow is strung, I can put two full twists in the cable, however, if I unstring the bow I can twist the cable three times.
I shot the bow with some store bought arrows yesterday. The first attempts were with the sinew cord untwisted and the bow string just tight enough to brace the bow (bracing the bow means stringing it so that the wood is flexed and it has the classic D-shaped profile). The arrows were travelling about 50 paces. I unstrung the bow and added a half dozen twists to the bowstring to make it shorter and added a couple full rotations of tension to the cable. With those two little changes the bow started shooting arrows 85 paces.
Tuktut Nogait Bow
from top; the original Inuvialuit artifact, with the Parks Canada reproduction sitting behind it.
The unstrung bow with the cable backing on (Western Yew, 50 inches, 127 cm long).
The braced bow.
The bow at full draw - 24 inches.
The effects of the cable backing are shown in the graph below. This time I was testing the draw weight of the bow by drawing the bow using a fish scale, and recording how many pounds were needed to pull it to 12 inches, 14 inches, 16 inches, etc. The red line shows the draw weight of the bow with no twist in the cable and the green line shows the draw weight of the bow with two twists in the cable. In both tests the tension in the bow string was the same. Without twists in the cable the draw weight of the bow at 24 inches is 28 pounds, with two twists in the cable the draw weight of the bow at 24 inches is 32 pounds - a 14% increase. The 3 twist test was done this morning, so the tension in the bow string might be different, but the results are consistent with the first two tests, this time it draws 34 pounds at 24 inches - a 21% increase. At the moment, 3 twists is pretty much the maximum tension that I can get in the cable.
nocks on the store bought arrows don't fit on it properly, so they break a lot.
Photo Credits: Tim Rast
First: The bow string at 90 degree angle to the limb - any farther and the string slips off.
Second: Holes in the wall and a dent in the chair from the bow flying across the room when the string slipped off.
Third: 2 ply sinew bowstring loop
Fourth: drying the twisted sinew bow string with tension
Fifth: Sinew twister in the braided sinew cable
Sixth: Tying down the cable using leather lashing
Seventh: Composite photo of the Elfshot reproductions and the original Tuktut Nogait bow
Eighth: Graph showing the effect of cable tension on bow draw weight
Ninth: Wrapping the sinew backing. 70 feet of braided sinew was used.