Trail Tool: Rock Sling for Moving up to 800 lb Boulders

A rock sling is a tool used for manually moving large rocks on the trails. They are very useful for trail building when the area is inaccessible to mini-excavators, or the cost of an excavator and driver is prohibitive.

With four or more people, a rock sling can be used to carry and move boulders weighing hundreds of pounds!

Combined with a rock bar for leveraging and moving heavy items onto the rock sling, a group of volunteers can build impressive rocky trail features.

Rock Sling

Rock Sling.jpg

Rock Bar

Rock Bar.jpg

Plans for the Rock Sling

Tom Erb designed a rock sling for GORC (Gateway Off-Road Cyclists) known as Spartacus. It was released under the Creative Commons license. The following are plans for the modified CANbike version.

Click here to download the Rock Sling PDF plans

Rock Sling for moving up to 800 lb boulders-page1Rock Sling for moving up to 800 lb boulders-page2

Specifications

Linear Chain Length: 36’
Weight: 13 lbs
Working Load Limit: 800 lbs
Diameter: 4’3”

Materials

  • 1/4” Quick Link (880 lb WLL) x 24
    Quick Link-WLL 800 lbs.jpg
  • 3/16” Grade 30 Chain (800 lb WLL) – 36 feet
    36 Feet of Grade 30 Chain.jpg
  • Rubber Hose – 11 feet
    i.e. Garden hose, rubber appliance discharge hose, etc.
    Handle-Hose.jpg

Costs

Canadian retail prices for parts were as follows:

Item Location Price Quantity Total
1/4” Quick Link (880 lb WLL) Rona $0.98 24 $23.52
3/16” Grade 30 Chain (800 lb WLL) Home Depot $1.29/ft 37 feet $47.73
Washing Machine Discharge Hose – 5’ Rubber Thrift Store $2 3 $6.00

Waiting for sales or buying bulk will reduce the cost.

Construction

Assembly of the rock sling was straight forward. Most of the time was spent counting the links for cutting and for connecting with the quick links.

Rock Sling Assembly

  1. The chain links to cut were marked with twist ties.
    Marking Chain Link to Cut.jpg
  2. The chain was then clamped tightly in a vise.
    Clamping the Chain for Cutting.jpg
  3. A hacksaw cut quickly and easily through the chain link.
    Cutting the Chain with a Hacksaw.jpg
  4. Cut pieces of the chain were then sorted out by size.
    The Cut Chain Pieces.jpg
  5. Quick links connected the pieces together to form the rock sling.
    Assembled Rock Sling2.jpg
    Assembly Tips
    • Inner Ring – Radial lines are spaced every 4 links.
    • Middle Ring – Radial lines are spaced every 12 links.
    • Outer Ring – Radial lines are spaced every 20 links.
    • Radial Chord Chain (18 Links) – Quick links are connected at
      • the 1st (inner ring),
      • the 9th (middle ring),
      • and the 18th link (outer ring).
    • Inner Ring Chain (50 Links) – Radial line is connected at
      • the 1st (outer ring),
      • the 10th (middle ring),
      • and the 20th link (inner ring).
    • Outer Ring Chain (178 Links) – Radial line is connected at
      • the 1st (inner ring),
      • the 9th (middle ring),
      • and the 20th link (outer ring).

Handle Assembly

  1. The hose was cut to 16” lengths.
    Cutting the Hose.jpg
  2. Links on the outer chain ring for quick link connections were marked.
    Marking the Outer Ring Chain.jpg
  3. A zip tie was tied to the starting outer ring chain link, and the chain was threaded through the handles.
    Threading the Chain Through the Handle.jpg

The completed rock sling

Completed Rock Sling.jpg

The completed rock sling folds up nicely for storage and for carrying over the shoulder.

Folded Up Rock Sling.jpg

Rock Sling in Action

Six people carrying a heavy rock over rough terrain during a trail maintenance.

rock sling in use.jpg


Creative Commons License
Rock Sling (800 lb WLL) by CANbike is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at http://gorctrails.com/spartacus.


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