Today I would like to clear the fog , so to speak, between a number of different types of rope or cordage. The overall umbrella of this group of lines is known as HMPE or High-Modulous Polyethylene. HMPE fibers are grouped and spun together to form strands. As explained in another discussions these strands are spun together in “S” strands and in “Z” strands. You can think of these two different strands as right hand twisted strands and left hand twisted strands. In the USA, The Honeywell Corporation produces this fiber and it is call Spectra. In Europe this same fiber is manufactured and is known as SP75. Spectra and SP75 for all intents and purposes is basically the same. This fiber is very unique and has some very interesting characteristics. First and foremost , it is very strong. In the USA the Spectra fiber is braided primarily into 12 strand rope or 12 strand Spectra. In Europe the SP75 fiber is braided into 12 strand rope as well and is called Dyneema. Spectra and Dyneema are basically the same.

In the USA , The Cortland Puget Sound Rope Company has the Patent Rights on a heat treating / recrystallization process whereby the Spectra is heat treated and the result is a line they call Plasma or 12 Strand Plasma. Just as steel gains a lot of strength through heat treating , so does Spectra. In Europe , the SP75 fiber or Dyneema is put through a similar process and becomes Dyneema HS or Dyneema Heat Set. Again the HS is a much stronger version of the former.

So for a comparison, Lets compare 5/8” Spectra / Dyneema and 5/8” Plasma / Dyneema HS to 5/8” stainless steel wire rope or cable. 5/8” stainless steel wire rope has a tensile strength = 31,400 lbs. Spectra / Dyneema has a tensile strength = 36,600 lbs. And Plasma / Dyneema HS has a tensile strength = 51,400 lbs. As you can see, massively stronger than Stainless cable.

Should you have further questions regarding HMPE lines, please see the attached spec sheets or email your questions to info@ropeforboats.com