CascadeClimber

The article is excellent. But it doesn't discuss the situation in question here. The closest illustration is #3, where the force generated by the fall is 5.7kN, but the top draw experiences 8.9kN. This illustrates the additive effect I was pointing out. But what is doesn't do is show that the force on the belay without the gear would be equal to the force of the fall. If the rope is run from the belayer to the belay anchor to the climber and the leader falls with no other protection in place (or the second falls at all) the resultant impact force on the belay anchor is significantly higher (double, ignoring friction) than if the rope is not run through the belay anchor. So if I am belaying on a shitty swedgie anchor, or bad screws, I don't run the rope through the belay, inorder to minimize potential impact force on it. If the anchor is bomber, I do, because it is more comfortable and the force of a fall on me is less, due to friction. However, if the force is high enough, I could do a face-plant into the rock or ice which would make me even uglier than I already am! -L

The force on the draw, and thus the anchor is STILL 1060, or thereabouts. Agree? No. The force on the anchor is not the same. It can't be if the sum of all the forces equals 0. The point I was trying to make, perhaps in an unclear manner, is that running the rope from the belayer through the belay anchor will result in the (near) doubling of the force on the belay anchor if the leader falls with no gear in above the belay (or if the gear fails), or if the second falls. A fall of either type tranmits twice the force to the anchor, less frictional forces, as it does if the rope is not run from the belayer to the anchor to the climber. So if I mistrust the belay anchor, I don't run the rope through it when I am bringing up a second or belaying a leader. Maybe this is better settled over a beer...

Here, from the Beal web site: In case of a fall, the anchor sustains a double load: that of the climber and that of the belayer. These two forces combine in a pulley effect. If the rope does not absorb enough energy, the load on the anchor point will be very high, with increased risk of failure… Rope with a low impact force is the key to limiting the consequences of the pulley effect. -L

Alex- You are right, the sum of the forces in x, y, and z planes must be zero, or some part of the system must be in motion. Where you are mistaken is in your assertion that the force on the anchor is constant. It is not. The constant in the system is the force related to the fall of the leader or second. Surely you can see that the y-vector downward force created by the fall cannot change as a result of the anchor system. F=MA, the mass of the climber times (in the case of a fall) the acceleration of gravity, 9.8m/s^2. What you are saying is that the force of the falling leader is different if the rope runs through the anchor. The orientation of the rope has nothing to do with the mass of the climber and the acceleration of gravity. It is counter-intuitive in this presentation, but if you think of it as a C-pulley, with the anchor as the victim, you know that the force required to hold the c-pulley in a static position is 1/2 the weight (in newtons or pounds-force) of the victim (ignoring friction). I'll go dig through my Statics book to find a reference if this still seems wrong to you. -L

What Forrest said. To look at it another way, it is a C-pulley system. 2-1 mechanical advantage, except it is a 2-1 mechanical disadvantage in this scenario. -L

Because to keep the system static, the anchor must absorb the force of the falling leader plus the equal force of the stationary belayer (less static and dynamic friction). This is the best pic I could find quickly: If you remove the rope from the quickdraw, the equal and opposite force on the anchor is only that of the falling leader. This also applies to belaying a second through the anchor. -Loren

It is worth noting that running the rope through the belay can effectively double the impact force on the belay in such a situation. If the belay failed you would end up with a much bigger problem than a tib-fib fracture. Sometimes I run the rope through the belay, and sometimes not. It depends on my opinion about the strength of the anchor system and the potential for a factor-2 fall. -Loren

<spray> Ice was found, fear was felt, fun was had, ice was climbed. </spray> -Loren

Looks good, Tim & Jon. The threaded mode is nice.

Make sure ta eat a pastie and take a sauna while yer der, eh. -Loren another former Michigander

quote: Originally posted by iain: what's with windshield repair places? How can they pay up to $100 off your insurance deductable and give you 25 free dinners to Shari's? Just how badly are they taking you to the cleaners? Call one of those places and ask how much for a windshield. Then ask them how much if you don't have insurance. The difference pays for those dinners and other perks, plus a tidy profit. It's quite a racket.

Washinton should subcontract its state government to Oregon. In the ten years I've lived in Washington, we've spent billions (BILLIONS) on roads and mass transit with very little to show. Sounds Transit has redefined futility and fiscal irresponsibility through unparalleled analysis paralysis. Meanwhile Portland has rebuilt their airport (almost from the ground up), extended their light rail to the new airport, and drilled a light rail tunnel entirely through the west hills to Beaverton. I actually heard a representative of the state of Washington on NPR last week. He was advocating reducing the sales tax and implementing an income tax. His logic: "Oregon has an income tax and they get better value per transportation tax dollar than Washington residents." I can't see how the form of the tax that generate a 'transportation tax dollar' impacts the skill with which it is spent, but I am sure than *any* proposal to tweak taxes will both increase the overall tax burden, and further bloat state government. Taxes are low in Washington. But we pissed away a tax windfall from the dot-com bubble and lost Boeing to boot. Until the state government demonstrates both competence and accountability, I'll never vote for another tax increase. Man, I really need to find some ice to climb. Maybe we could make the ice season longer by sprinking salt on it?? [ 11-25-2002, 11:20 AM: Message edited by: CascadeClimber ]

Water containing dissolved sodium chloride has a lower freezing point than 'plain' water. The idea is to create a wet salt-water layer on the road so that falling snow melts rather than compacting on the road. They add rock salt to make up for the salt-water that runs off into nearby streams and lakes. How much lower the freezing point is depends on how much salt is dissolved in the water. About once every five years in Michigan it would get cold enough to freeze the salt-water on the roads. That made for really great entertainment, as the roads became sheets of ice and there was nothing they could do (they didn't use sand/gravel at all).

<RANT> I've lived 11 years in the Northwest preceded by 23 years in southeast Michigan. Salt does far more damage to cars and roads than sand and gravel. The first two cars I owned rusted through the wheelwells, trunk, and the floorboards in a few years. The salt also eats the roads, causing large and plentiful potholes. The ruts caused by studs are bad, but not as bad as potholes. And salt washes into waterways and causes problems there, too. This is really bad news. And the state government is astonished that voters are pissed off and distrustful. Go figure. Maybe if they hadn't pissed away billions on Sound Transit with almost zero meaningful results, they'd have a few thousand dollars to buy de-icer. </RANT>

Top Five Highlights - Leading the third pitch of Icy BC (in admittedly easy conditions). - New route on Formiddable - Finally climbing Little T (aka Choss-daddy), car-to-car with great skiing. - Lots of ice mileage - Not getting killed, maimed, scared out of my wits, divorced, or going broke. Failures - East Couloir on Cutthroat. - Got completely spanked on a new line that I'd been scoping for a long time. I totally underestimated the "easy" section. I'll be back...

Pub Club at The Reynolds' Bar! True Story: We got back The Reynolds after dinner one night last season and some of the windows were broken out and being boarded up. I asked the woman at the front desk, "So, what happened with the windows?" "Someone at the bar didn't want to leave." And I guess Pub Club-Lillooet would technically be an east-side event, too. ice ice ice ice ice ice ice ice ice ice

quote: Originally posted by JayB: Anyone else recall what they felt and or any changes in their perception of ice climbing after their first stiff lead? Yep. I perceived that I needed a change of underwear. -Loren

Can you elaborate a bit more? "In" as in climbable with no gear? Which of the pitches? Any news on the stuff up in the Bridge? TIA- Loren

I called and made a lost & found report: Make, model, where they were last seen, etc. Someone down there compares the lost list to the found pile and sends matches to the owner. No charge for shipping, either. Quite a nice little system. -Loren

I seem to have particular problem with poles, which I go through like potato chips. But lately I seem to have lost the time and motivation to climb. If anyone finds my mojo could you please send it back to me? ;-) Loren [ 10-29-2002, 11:51 PM: Message edited by: CascadeClimber ]

Well, exactly one month after my post I come home and find a box on the front step from MRNP. Inside are my missing shoes. I'd sure like to know where they've been... My thanks to whomever turned them in. -Loren

Phair Creek! Phair Creek! Phair Creek! Phair Creek! "Let the powers that be keep the Phair Creek road open. Cause 'A Phairwell to Arms' just looks totally dopin!" Ice! Ice! Can someone sedate me until mid-December, please? -Loren

I've only been up there once- December 23, 1996. Clear, blus skies and plenty warm. But then we were able to park directly across from the 'trail'. I take it that the spur road is now gated or undriveable? -Loren

I suspect some the hazardous enigma value has been mitigated by liberal use of flagging tape and a pair of loppers. Did you solo down the gully or rap? It looked nasty loose to me, but maybe not? -Loren

This is terrible, sad news. My sincerest condolences to family and friends. I live in Issaquah. Please let me know if there is anything that I can do. -Loren