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General Climbing Discussion

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dynamic belaying? confused! 4-Nov-2005 At 10:35:15 AM Ronny

Message

>On 3/11/2005 JCP wrote:
>>in response to patto:
>>
>>>By introducing more slack into the system the fall factor and thus the
>>forces involved increase
>>
>>NOOOOO!!!! etc etc...
>
I think you guys are talking about different things.

I think patto is saying that if you just poured on a couple of armfulls of slack to 'increase potential stretch' and then belayed as normal, then this will tend to increase the fall factor. This is right. (This isn't strictly true, the fall factor will approach 1 - but as the type of falls we're talking about are generaly <1 then that doesn't really matter). The thing is that the increase is very small, but this will make a difference to how hard you're pulled into the rock, so its probably good anyway.

JCP on the other hand is keeping the rope length the same and jumping. This won't increase the fall distance, but will increase braking distance. (fall factor becomes irrelevant because as a tool for comparing forces it is only useful when the only thing that affects braking distance is rope stretch - but the jump has changed that.)
So JCP is right - less force.

I think a 'dyniamic belay' will generally do a bit of both of these. The jump more than accounts for the increased fall distance due to the slack, the climber doesnt' slam into the over hanging wall - and everyone wins (except the guy who falls on a slab and slides 5 more metres down the sandpaper than he has to)
J