Mast Climbing Setup

What follows is a description of the system I use for mast climbing, recorded here for my own reference.

Any equipment, system and technique you choose to use is your personal choice, and you use at your own risk, whether influenced by the information on this page or not. You alone are responsible for making choices that relate to your personal safety.

HUGE THANK YOU to climbing instructor Ross Ayer for all his invaluable input and insight!


  • Fully redundant safety
  • Solo operation
  • Head above top of mast


Main System

Backup System

  • 50′ semi-dynamic 10.2 mm climbing rope for backup
  • 2x Sterling Auto Block 6 mm x 13.5″ loop (for Prusik knots)
  • Petzl Grigri 2, stowed in reserve if needed (i.e., for self-recovery after failure of primary Grigri)



  • Figure eight on a bight on halyards with 18″ tail
  • Figure eight on a bight on ascension ropes with 8″ tail
  • For each halyard-to-ascension attachment: Two carabiners, oriented 180° from each other, positioned so that the pull of gravity tightens the screw gates
  • Hoist halyards and secure well
    • Tie a knot around winch?
  • Thread ascension rope into Grigri, climber side is toward the top of the mast
  • Attach Grigri to harness using Attache carabiner (small elbow for Grigri)
  • Attach ascender to ascension line
  • Connect foot loops/steps to ascender with carabiner
  • Tie Prusik on backup line – use three wraps
  • Connect Prusik -> carabiner -> 60 cm nylon runner (doubled over to 30 cm) -> carabiner -> harness; Prusik connection to harness is above connection to Grigri
    • Alternatively, tie a basket hitch by threading runner through both hardpoints of the harness (where the belay loop connects) and putting the ends into a carabiner attached to the Prusik.

Technique – Ascent

  • Double-back the harness waist strap
  • Test running & jamming of rope through Grigri to verify it is threaded properly
  • Get hanging so that feet are not touching ground
  • Use legs to “stand up” in foot loops while simultaneously pulling up on Grigri braking line
  • Never let go of Grigri braking line unless it’s secured with a knot right at the device
  • When weight is back on Grigri, slide ascender up rope
  • Slide Prusik up as far as possible so there is no slack in connection
    • Hold bitter end in Grigri braking hand to assist sliding
  • While ascending, tie overhand-on-a-bight every few feet to limit drop potential of Grigri
  • At the top, tie overhand-on-a-bight right at Grigri, and connect bight loop to harness belay loop with a (separate) carabiner
  • Always be deliberate to make sure there is never a way to “fall” on the Grigri or the Prusik – at all times they should be snug with no slack so they can hold your weight, but do not rely on them to brake a fall (something will likely fail under the shock load)
  • Do not unscrew the Grigri or Prusik carabiners once in the air

Technique – Descent

  • Use Grigri to bear full weight
  • Detach ascender from rope and stow
  • Keep Grigri braking line firmly in right hand at all times
  • Using left hand on Grigri lever, gently and smoothly lower to the next knot
  • Stop, untie the knot, and replace right hand onto braking line
  • Slide Prusik as needed
  • Repeat until fully descended


  • Immediately replace any suspect piece of equipment
  • Replace “soft goods” (harness, runners, ropes, etc.) after five years of service regardless of apparent condition

References & Resources

✨ Join the Journey ✨
✨ and Enjoy Exclusive ✨
✨ Access and Benefits ✨

Leave a Reply

Your email address will not be published. Required fields are marked *