Splicing an Eye into Spectra, Amsteel, Dyneema – 12 plait line

March 10, 2011

100% AmSteel Blue SK-75 Dyneema

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).



  1. My application, using Amsteel as a centerboard pendant for my sailboat, won’t allow for the Brummel splice because the eye is made through a hole in the centerboard. How can the Class II eye splice be made more secure, or is there yet a different way to splice in this application?

    • Hello Ed, yes there is another way to splice the Amsteel line and according to Sampsn Rope, it is actually used quite a lot. Here is a link to their instructions for the Eye Splice for Class 2, 12-Strand Ropes: http://www.samsonrope.com/site_files/12S_C2_EyeSpl.pdf It is a direct bury type of splice with a taper and stiching.

      It references a fid length of 3-1/2 lengths for the bury which is based upon the common fid for the line. If you are not using a common fid it helps to know that this is based upon the standard fid being 21 times the line diameter. For instance, if the your 12 strand line is 3/8″ diameter, the fid would be 7.87 inches long and the bury would be 3-1/2 times that, which is approximately 27-1/2 inches long. Hopefully that length will be workable for you. Don’t gorget the stiching!

  2. I loved your demos – very clear and informative. What size fids should one use to splice into 7/64″ Amsteel line? Thank you and be well. Doc

    • One of the many nice things about splicing Amsteel is that the fids used are not as rope diameter dependent as the other types of rope. This means that a relatively small set of tools can be used for a wide variety of rope diameters, whereas double braid requires one fid for each rope diameter.

      There are two types of fids used to splice Amsteel. One is for the tucking and one is for the burying. For the tucking aspect, a ballpoint pen can be used for the small diameter Amsteel, or a 1/4″ double braid fid. Basically, anything that can pierce the 12 strands (6 on each side of the fid) to provide an opening large enough to tuck the rope through itself.


      For the burying step, the best way to splice 7/64″ Amsteel is to use a 2-3′ piece of seizing wire (monel or stainless), bend it sharply in half and put a pigtail on the ends for tugging. This “fid” will fit nicely up through the hollow core of small diameter Amsteel and allow you to pull the bury down through the standing part.


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