Wednesday, November 18, 2009

What are the parts of a Toggling Harpoon?

Here's a quick look at the parts of a Dorset Palaeoeskimo toggling harpoon and some of the tests to find a good ballistics gel seal to do harpoon experiments with.


This style of harpoon is used to attach a line to a seal. The hunter gets close enough to the seal to jab it with the harpoon, the harpoon head detaches and toggles beneath the skin of the seal. The hole where the line attaches to a toggling harpoon is near the middle of the harpoon head, so when the seal tries to escape, the harpoon head toggles, or turns sideways. A toggled harpoon head is bigger than the hole it made going in and is firmly embedded in the hunters prey. The line is used to haul the seal out of the water so that the hunter can finish it off.

That toggling action is one of the things I'm trying to illustrate with the ballistics gel seal. This particular video still doesn't show the harpoon head toggling, but I did learn a lot from it. One thing it illustrates is that the skin and fat layer of the ballistics gel seal work very well. They offer the right amount of resistance and are good approximations of the outer layers of a seal. The Dorset Palaeoeskimo harpoon heads from Newfoundland that I have modelled this harpoon on have a single line hole, and I believe that the line must have been secured to the harpoon head with a big knot of sinew on one side. On the test in the video, the sinew knot bulged out of the smooth contour of the harpoon head. It created a raised bump a couple millimetres high, but it was enough to snag on the rawhide skin. The resistance from that tiny snag was enough that the harpoon was bound up and the whalebone foreshaft broke. I learned two things. First, if I'm going to use a sinew knot to secure the line, it needs to be flush with the surface of the harpoon head and secondly, the forces involved in the experiment are great enough that things break when they go wrong. Which is also good, because examining how things break is very useful information when studying broken and discarded tools in the archaeological record.

video

After the foreshaft broke, I pushed the harpoon head down into the gel manually and it did toggle for me when I pulled on the line. In the photo below, you can see the gel tube suspended from the toggled harpoon head and line. The gel is still a little opaque to see everything that's going on, but you can make out a few interesting details. In the overhead shot, you can see the hole that the endblade made and the shadow of the harpoon head lying beneath the rawhide skin. In the inset shot you can see the endblade, which detached when the harpoon head toggled. It marks the depth that the toggling occurred, although the harpoon head itself squished up through the ballistics gel "fat" layer and is actually snagged just below the skin. You can see the rubbery rawhide skin flexing upward under the tension.
Photo Credits:
First, Second: Tim Rast
Video: Lori White
Third, Fourth Photo: Lori White

Photo Credits:
First: Labelled parts of a Middle Dorset Harpoon Reproduction, Elfshot 2009
Second: Showing the detached harpoon head
Third: Detail of video frame showing the sinew knot in the harpoon head line hole when it grabbed the raw hide.
Video: Testing the ballistics gel. The foreshaft breaks when the harpoon head snags on a knot in the sinew
Fourth: The harpoon head toggling in the Ballistics gel.

7 comments:

  1. Great demonstration Tim!

    From watching the video many times over - and frame by frame - I think the foreshaft broke because of how you stabbed at the target. From the direction of the thrust, and the flying foreshaft (toward the camera) after impact, it appears the foreshaft bent and ultimately snapped under the force of your thrust and the resistance of the gel.

    I'd propose that in order to avoid foreshaft breakage, that the harpoon needs to be used in a jabbing motion. As such, the more skilled Dorset seal hunters would know: (1) how much force to apply, and (2) when to pull out.

    I suspect that if you pulled out at maximum resistance you would have saved the foreshaft and left the harpoon head at maximum depth. In this regard, I don't think it necessarily was equipment failure, but rather, hunter error.

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  2. I think the seal's own response to being harpooned (diving) would also determine the maximum depth of the harpoon head.

    Given the limited surface area of the gel seal shown above, and the restricted space of our kitchen, I don't think it was possible to use the appropriate force (and varied angle) that might be used if you were harpooning a life-size target in an open area. I hope you get the chance to harpoon a 1:1 gel seal target on your next R&D trial!

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  3. I think Lori is right about the seal being responsible for the tension in the line. That will be a challenging thing to replicate in the experiments. I don't think the hunter jabs in and then out, I think he would have just stabbed once and the line would go taut when the seal immediately recoils from the shock of being harpooned.

    There was some resistance in the gel, but the endblade cut through that easily. The snag was definitely on the rawhide between the sinew knot and the skin. If I would have anticipated it, I might have been able to change the direction or angle of the harpoon thrust to avoid the contact.

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  4. If we could make a thick enough gel seal "blanket", perhaps we could wrap up one of the nieces or nephew and put them in the pool. You'd have to make sure it was a REALLY thick blanket... I'm attached to all three kids.

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  5. Edit: I added a screen grab to the post of the moment the harpoon head bound and the foreshaft broke. It shows the knot where it grabbed the raw hide skin a little more clearly than in the video.

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  6. I think you need to head north to a community where a person living a traditional native lifestyle with the appropriate hunting permits can take part in this experiment! There must be someone still using similar techniques?

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  7. Yeah, harpoons are still being used in the north, although they tend to be made of tougher materials than antler and whalebone these days. A few years ago at the Folk Festival, an elderly Inuit man from Labrador picked up one of my Palaeoeskimo harpoons and he said I was on the right track, but he pointed out a few design improvements in the harpoon head and overall heft of the implement. All of the suggestions he made were changes that his Thule ancestors made in their harpoons over the earlier Paleoeskimo designs.

    If I can get the bugs worked out of my reproductions in the ballistics gel tests, I'd love to do some field trials with Inuit hunters who have experience with modern harpoons.

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