The elongation of a rope made with Dyneema® is minimized through this treatment called Heat Prestretch Setting which is irreversible. It regulates the tensioning of the fibers that make up the rope and sets them in an optimal way, bringing them to a high-temperature and subjecting them to a constant load for a given time. The result is a rope with a very high specific modulus, without construction elongation and a higher Breaking Load if compared with non prestretched products.
Without HPS treatment
Single braid Dyneema without HPS treatment: this braid is soft and “airy”
After HPS treatment
The same braid after the HPS treatment: the fibers are oriented and the rope is more rigid and compact
Ropes with the hps treatment
As mentioned above, the advantages of this treatment are obvious.
It is clear that the HPS treated rope is much more compact, less flexible and therefore also a few tenths of a millimeter thinner than a rope with the same non prestretched core. Therefore, when choosing a rope, we must carefully consider the technical level of our boat because, the higher the technical level of the selected rope, the higher and more appropriate the technical level of the deck equipment and of the crew should be.
For which running rigging is the hps treatment recommended
It really depends on the type and on the technical level of the boat. In any case, the HPS treatment is to be preferred on halyards. In this application, the slightly higher stiffness of the ropes will not be a problem, as they are used much less than other lines. On high-level racing boats, almost all the running rigging is made with prestretched ropes. These prestretched ropes can, however, be composed of different fibres and can be made up with covers of different compositions.
Header photo: A braid with Dyneema® inside the infrared furnace, undergoing HPS treatment.