WorcsWuss

So the force applied to the tail makes no difference. Which is where I get lost again..... If that follows then the force applied to the anchor should be double the climber's weight no matter where he's anchored..... Hold on, is that where dynamic forces come in? To just hang there ddrt it's 100kg. To start hauling yourself up ddrt you need to exert 100kg of force on the tail to lift the 100kg dead weight on the standing line which is the climber. So when hanging ddrt the anchor is subject to 1kn of force, but when climbing it's subject to 2kn of force.... And a base anchor always exerts 2kn of force because the load is never split between the same point...... I'm going to just switch the lights off and lie here in the dark for a few minutes......

This is where I become confused, because if we're talking force on the end of the line, which is where a base anchor comes in, adding wraps round the tip reduces the force which must be exerted on the tail of the rope to support 100kg of weight by using friction, but the 100kg is still exerting 1kn of force on the anchor point...... So you could have 100kg suspended, but by taking 3 or 4 wraps round the limb, only have to exert 0.25kn on the tail of the rope to suspend it. So, are you exerting 1kn, 2kn or 1.25kn of force on the anchor....?

Still don't get it, I never was much cop at applied mathematics and engineering....! What I can't fathom is how one end of the rope being attached back to the climber makes any difference to the force applied to a limb when compared to one end of the rope attached to a static point.... I'm having a thick day! Ref the tie in point, if a limb is suspended by natural rigging with a rope thrown over a branch, a small amount of friction is generated to aid controlled lowering. If the piece you're lowering is heavier, you take a couple of turns round it to reduce the amount of force needed in the tail of the rope to lower it, same principal as a capstan. So the force on the tail (or theoretical base anchor) is reduced, but the force on the limb you're rigging from remains the same. So while i understand the reasoning, i can't understand the maths which mean a 100kg suspended on a loop from a point exerts 50kg down each leg, 1kn in total, but if you unclip it from itself and fix it back to a static point all of a sudden it generates 2kn of force on the limb...? (Have I got the units right there?) This is why I use structural engineers when I'm designing a building!!

There's only one way to find out.......

Not arguing by the way, just want to make sure I fully understand the principles behind it! Explanation appreciated!

True, but presumably a large limb with say 400mm of rope in contact with it will exert an amount of friction on the rope which will reduce the force required to resist the force, the same principal as using friction to lower cut timber....? And I guess a smaller diameter limb would create less friction requiring more force to counteract the exerted weight. Only over a friction free pulley would the force be the same both ways. But I would still have thought half the exerted force, the main principle behind ddrt?

Presumably the amount of friction around the limb will affect the amount if force necessary on the opposite side to counter act the force from the climber?

Just for my own curiosity, can someone do the maths for me? I just can't see how it can be the case.... Secondly, is there a necessary clearance and minimum tether length for the rw to work? I've been browsing all the off the shelf stuff as a starting point and the best stuff I find is around 20 / 25 cm... Is this too short...?

Deja vu.... :lol: How much was it....? I still prefer the rw concept though I reckon....

And there was me thinking it was the 'SCAM ITEM, ACCOUNT HACKED' title....!

Ooh now I do fancy a uni.....!

What makes you think that.....?

You could launch yourself up with that lot Dan..... I tidied through my gear yesterday, made a list of the next tranche of purchases.... RW is in the shopping basket, do I don't I.....

Without seeing it i have no idea really, but in general it depends if it could hit something, always better to have control. Rather than having a free flying tag line you could control it yourself through a friction hitch. You've got a haul back line then as well..... Depending on the angle and size of the bits you're dropping you could lock it off with a prusik rather than portawrap....?

Interesting..... Another nail on the zig zag coffin for me....

I believe zigzag, bulldog and unicender can all be used in their own. Spider / lock jacks need additional friction management....

I concur....

Tempting, very tempting.... On the birthday list I reckon....

Both Chris, depends what I'm doing. Both my current strops have vt's on them, one is 9mm boa, super long one which i also use as a second line now has 8mm OP, both on isc micro pulleys. I make strops up regularly out of odds and ends I find lying around.....! Cheers Paul, I might give one a go...

2 things.... I'm making up a new lanyard (as discussed elsewhere... ) and I think I've settled on 5m of 10mm OP with 8mm Sirius or similar... For now I'm going to hold off on a cinch. Any who, I dislike clutter, particularly on my bridge, so rather than a micro pulley like I have on my other strops, I'd like to use an hc or skywalker so I only have one krab on my bridge. I like my hc but it seems a bit over the top for a strop and quite bulky, so I'm thinking of trying a skywalker. Does anyone have both and could you post a photo of them together so can get an idea of any difference in size? I'm hoping the stein pulley is smaller..... Second....best solution for base anchor? I tend to use plain ended cut lengths of rope for everything, but I'd prefer something a bit more purpose made to attach my new static rope to the bottom of the tree. The cheap and cheerful solution is a length of 16mm bull rope..... What's better....?

You might drop lucky and find a MS460 for that, if not maybe an 046...... I love my 460, 25" bar, great saw..... I sold a nice 460 for a shade over £300, but it was a nice one. You ought to find something a bit more tatty within your budget....

Good call! Sacked the saws off the bench, time to wax the base and polish the edges!

I'm in a similar situation, but I just can't help myself, I love having the gizmos....! I spent a few quid on a closed hitch setup comprising hitch climber rapide, 75cm Yale beeline 8mm eye to eye cord, pair of DMM Ultra o crabs and a multi-saver, it's a lovely way to climb. Just got a pulley saver today to replace my practically unused multi saver as well..... Would recommend it. Going to order a rope wrench now so I can use it for SRT as well....

Where do I start....! Camera SUCKS BIG TIME. Battery life stinks. Call handling and signal retention a bit hit and miss. Tiny memory Grossly overpriced.... I could probably come up with a load more in the morning.....!

I'd like to do a db one if the dates fit Nod....