Splicing an Eye into Spectra, Amsteel, Dyneema – 12 plait lineMarch 10, 2011
One of the popular new ropes and lines on the market is HMPE, High-modulus polyethylene fibers produced by gel-spinning ultra-high molecular weight polyethylene (UHMWPE). HMPE is manufactured under trade names such as Spectra, Amsteel, Dyneema as well as others. This process makes rope as strong (or stronger than) steel for its size. It is also really light weight; enough so that it floats.
This HMPE rope does have a few characteristics that make it more challenging for splicing. It is a ‘slippery’ product and subject to ‘creep’. The rope is also most commonly served as a 12 plait braid. Having noted these two characteristics, the HMPE rope is perfect for use in the marine industry and any service industry trying to match the strength of steel in a floating product. Dyneema is so strong that it was used to install the first span of the New Tacoma Narrows bridge in place.
There are two types of eye splices for HMPE rope. The Brummell splice, which when done correctly retains 80-90% of the rope strength; but requires more skill and patience. The Samson “tail in rope” splice which retains 90-100% of the ropes strength, holds with a load on it, but easily comes undone without a load if it does not have a lock stitch
The most common – and strongest eye braid is the Locked Brummell Splice. New England Ropes demonstrates the Brummell Splice well.
Brummell Splice part 1
Brummell Splice part 2
A simplier eye splice is the Samson 12-strand Class II eye splice. This is a simple, all-purpose eye retains 90-100% of average new rope strength. An eye is formed into the rope and the tail is buried into the standing part. The key to using this simple splice is to make sure that you use a lock stitch.
The following video compares a Brummell splice with a tail in rope eye splice (with NO locking stitch).