What is Dyneema all about?

The underlying fiber, and the rope itself, is getting stronger, but the fiber still exhibits creep. Creep is a physical phenomenon similar to elasticity but does not recover when the load is removed. The modern versions of the fibers have dropped creep down to very manageable levels. In critical applications like standing rigging, creep is practically eliminated by upsizing the rope.

Most of the rope on the market today is made with SK60 and SK78 fiber, with SK78 being 20% stronger and with lower creep than SK60. We are starting to see SK99, with even more strength and less creep. The cost of SK60 and SK78 is converging, and SK60 is beginning to phase out.

Dyneema is used in two primary constructions: 12-strand single braid or double braid rope with a 12-strand core and a Dacron cover. We are going to concentrate on 12-strand single braid.  

Single braid is used as a replacement for wire rope in applications like boom vang cascades, backstay adjusters and anywhere wire rope was used. With proper implementation, Dyneema performs well enough to be used for standing rigging.

Common examples of Dyneema rope are Samson Ropes Amsteel (SK60) and Amsteel Blue (SK78). New England Ropes makes Endura Braid with SK78 fiber. SK75, a predecessor to SK78, is still used in heat-treated ropes. Newer fibers don’t heat treat as well. Hampidjian makes a heat-treated SK75 single braid called DynIce Dux. The heat treating allows for more fiber to be packed into the same diameter, strengthening the rope, and dramatically reducing creep. New England has a similar heat-treated rope called HSR-75 made with SK75 fiber. --B.P.