sac anchors ii lecture chris mcguinness 11/08/06
DESCRIPTION
SAC Anchors II lecture Chris McGuinness 11/08/06. (Original slides by Clint Cummins, modified by Chris McGuinness). What we’ll cover. 0. Knots 1. Placing Gear 2. Constructing Gear Anchors 3. Multipitch Climbing Sequence 4. Multiple Rappels - PowerPoint PPT PresentationTRANSCRIPT
SAC Anchors II lecture
Chris McGuinness11/08/06
(Original slides by Clint Cummins, modified by Chris McGuinness)
What we’ll cover
• 0. Knots
• 1. Placing Gear
• 2. Constructing Gear Anchors
• 3. Multipitch Climbing Sequence
• 4. Multiple Rappels
• 5. Where to go from here (transition from toprope/bolted to gear climbing)
What we won’t cover
• Actual climbing techniques (jamming, chimneying, etc.)
• Leading
0. Knots
• Overhand on a bight
• figure-eight on a bight
• water knot
• Double fisherman
• girth hitch
• clove hitch
• Munter hitch
• prusik
Double Fisherman
Clove Hitch
1. Placing Gear
• General concerns:
• rock quality (hardness, fractures / thin flakes / loose pieces, sand/dirt/leaves/moss/grass)
• surface area contact
• direction of pull
• ease of removal
Gear types
• Fixed:– Trees– Rocks (horns/boulders, tunnels)– Bolts + Pitons
• Removable:– Nuts (Stoppers, Hexes)– Cams (Camalots, Friends, TCUs, Aliens)– Tri-Cams
Trees• Preferably living• Ideally the size of your
leg• Sling as low down as
possible
Horns, Flakes, Tunnels
• Pay special attention to rock quality• Girth hitch feature securely, and be aware of the
possibility of the sling getting pulled up by the rope
Fixed Gear
• Inspect gear before just clipping– Pitons get old, rusty and can break– Fixed nuts are often not as fixed as they appear
• Generally a visual inspection, followed by a good tug while observing if the piece wiggles around is sufficient
Bolts
From ASCA (American Safe Climbing Association)
Hex nut - surface area
More Hexes
Stopper - sizing + orientation
Cam - placing or removing
Camalots - selecting size
Good - Strong + stable Not so good - unstable Bad
Friends - selecting size
good Not so good bad
Friend sizing - smaller crack
Too tight (hard to remove) good Not so good
Clipping gear in anchor or lead
• Orient biner so gate does not touch rock
• Do not load biner over rock edge - use sling
• Do not girth hitch sling directly to cable of nut or narrow bolt hanger - could be cut
• Do not load solid shaft of Friend over edge
• Avoid loading cable of TCU over rock edge - could be bent permanently
Tri-Cams
2. Constructing gear anchors• SRENE =
– Solid (invididual placements)– Redundant (independent)– Equalized – No Extension (if piece fails)
• Add: – Efficient (simple, fast)– Stable (robust to movement / changes)
Standard placement counts
• 3 strong placements, at least one multidirectional for lead anchor
• say 1/100 chance of random failure due to unobserved factors. If placements are independent, then:
• 1/10,000 chance of failure for 2 placements
• 1/1,000,000 chance of failure for 3 placements
# of anchor pieces - exceptions
• 2 “good” bolts:• good = 5/16” or larger, not rusty• suspect = surface/smooth rust or 1/4”• bad = corroded/pitted rust and 1/4”• 1-2 good trees (still use 2 slings/biners)
• more than 3 pieces? Too complex, unless some are weak; violates Strong rule, but is sometimes unavoidable
Joining pieces A: Clove hitch
Joining pieces B: slings
Joining pieces C: Cordelette
Joining Pieces D: Equalette
Joining placements in anchor• A. Clove hitches on climbing rope• +: strong, quick, no extra gear needed• -: questionable equalization, must retie if not swinging leads• B. Slings (with knots or clove hitches to adjust)• +: good for toproping, 1-2 points to clip on leads• -: reduces slings available for next lead, hard to equalize well• C. Cordelette• +: single point to clip, good for leading in blocks• -: requires carrying extra 1-2 pieces of gear, may not be long
enough to reach all placements• D. Equalette• +: Same advantages as cordelette, but better equalization• -: Takes additional time if limiter knots must be retied
3. Multipitch climb sequence
• Safety on approach (rope up on demand)
• Tie in and check knots/harnesses
• Bottom anchor if exposed ledge, leader outweighs follower, or ledge fall possible
• Location of belay anchor (to side)
• Clipping to belay anchor
• 2 Clove hitches, or Daisy chain + 1 clove
3. Multipitch sequence (cont’d)
• Stacking belay rope (and second rope)
• Lead belay position
• Feed out rope; some slack for quick clips
• Space to bring braking hand to side/back
Special risk - Factor 2 Fall
• Problems:
• A. High force on belay anchor - could fail
• B. Difficult to hold leader fall. Friction of rope running over biner makes 50% easier!
• Solutions:
• A. Clip rope through quickdraw on anchor
• B. Leader places 1-2 strong pieces early
4. Multiple rappels
• Four main risks:
• A. Rappel anchor fails
• B. Rappel off end of rope (sometimes due to uneven length ropes)
• C. Loose rock knocked by rope onto climbers
• D. Ropes hang up during pull
Munter Hitch
5. Where to go from here
• Transition from toproping / bolted climbing to gear climbing
• Practice placing gear• Practice crack climbing skills• Make a list of climbs you want to do• Find partners with similar abilities and
goals (or more experienced, occasionally)• Start leading easier climbs