Boat Rope

The vast U.S. cordage market allows us to have several competitive options including; Robline, New England, Samson, Yale, and Marlow Ropes, just to name a few. Each one of these manufacturers provide various rope constructions utilizing different materials to allow the consumer to achieve different functions based on application. All of the jargon like Spectra, Dyneema, Vectran, Kevlar, Technora, Dacron, Double Braid, Single Braid, and Three Strand, can be quite confusing sometimes. Let’s see if we can’t help explain some of the basic differences.

Rope Fibers:

Dacron is another registered trade name for Polyester. Its characteristics are; it’s extremely U.V. stable, chafe resistant, pseudo moisture absorbent, and a little stretchy (comparatively speaking), but soft in the hand and tends to run very freely depending on its construction.

Technora, basically Kevlar‘s replacement, comes from the Aramid family. This fiber is more stable in a U.V. environment than Kevlar (although, it would not be my first choice for U.V. resistance), it is susceptible to chafe, it does not absorb moisture, it is extremely low stretch, and is fairly heat resistant, but it does get stiff and rigid after heavy loading.

Spectra and Dyneema (synonymous products but different trade names) have more use in a wide array of applications. Spectra (or Dyneema) does not absorb water, is very strong, is very chafe resistant, and has a fair U.V. stabilization, it is also very low stretch, but is sensitive to excessive heat. This line material tends to stay more supple than Technora or Vectran, but is never quite as soft as Polyester.

Finally, we have Vectran which has combined some of the features of both Spectra and Technora. Vectran offers better heat resistance than Spectra and also lower elongation. Although fairly chafe resistant, this fiber will tend to be a bit more rigid than Spectra when loaded  and offers very little U.V. stabilization.

Rope Construction:

Double Braid, the most common type of rope construction in today’s sailboat market, is a two-part braided  line, one part cover and one part core. Double braid line usually will have a polyester cover and a core made from either Dacron, Spectra, Vectran, Technora, or some sort of blend thereof. It is also possible to find blended and exotic covers.

A Single Braid is typically a twelve strand braided line. This construction can typically be found in the core of a double braided line. Single braids can be coated to add U.V stabilization if necessary. Typically single braids are not good to put your hands on because they have a small diameter relative to their load capacity and can be slippery.

Lastly, Three Strand ropes are the more traditional looking right-hand-lain or twisted ropes that we will hardly use anymore in modern applications, unless it is for dock lines at which point Nylon becomes the preferred material due it’s elasticity, strength, chafe resistance and ultra high U.V. stabilization.

The way a rope is constructed, not just its material, plays a big part in how a rope performs, parallel fibers typically stretch the least, braided fibers usually provide some stretch or elasticity, and three strand line usually ends up being very stretchy and has a very elastic effect.

Hopefully this clears up at least a little of the technical jargon associated with rope. To find out what is the best product for your application needs please see your local rigger. You can read more about rope selection and maintenance here.

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