Y-hang

Vertical caving terminology and methods > SRT basic terms

Y-hang

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Y-hang made from a bowline on a bight. The traverse line comes in to the middle of the Y.
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Y-hang made from a double loop figure of 8. The traverse line comes in to the middle of the Y.
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Y-hang made from a pair of alpine butterfly knots. The traverse line comes in to one side of the Y.
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Y-hang made from a pair of directional figure of 8 knots. The traverse line comes in to one side of the Y.
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Y-hang made using the multiple bowline technique. The traverse line, if there were one, would come in to one side of the Y, but in this example, there is no traverse line, so the upper knot is a stopped bowline.
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Y-hang set up for pulling through. The rope on the left is used for SRT, and the rope on the right is used for pulling the rope down the pitch.

A double attachment point, usually used at the top of a pitch, to share the load of the rope and caver, between two attachments instead of one. Provides redundancy, so that if one fails, there is a second one to take over. Allows fine control over where the rope hangs between two walls of a pitch. This is useful for avoiding rub points, or to avoid the knots rubbing against the rock. As long as the angle of the Y-hang (between the arms of the Y) has been set up to be less than 90°, which it is supposed to be, each attachment point sees less than the full load. On average, they will each see more than half of the load. At a perfectly balanced Y-hang with an angle of 90°, each attachment point would see 71% of the load, pulling towards the knot. At an angle of 120°, each attachment point will see the full load, removing one of the benefits of using a Y-hang. At angles greater than 120°, each attachment point sees more than the full load. This effect is particularly noticeable with the Y-hang used for a pull-through.

Calculating forces on a Y-hang.

Assuming an equally balanced Y-hang, the force on the anchors of a Y-hang can be calculated with the same formula as a Tyrolean traverse:

0.5 × load on the rope / sin( angle of the arm from horizontal )

where:

angle of the arm from horizontal = 90 - ( angle between the arms / 2 )

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