There are several factors that affect marine rope performance. The main two are the construction and material. Today we’re going to talk about construction differences in marine rope.
The major construction difference comes in the form of a double braid line and a single braid line. Although, it is hard to just talk about construction without discussing material differences so we’ll get to the a little later.
A single braid, at its most basic, is a braided line that has no cover and no core. Because of that single braid lines are sometimes referred to as a ‘hollow braid.’ Generally in sailing single braid lines have 12 independent strands that are braided together. You can almost accordion the braid open and closed by pinching it between your fingers and pushing it open and closed. Single braids tend to be soft and malleable.
One downside of single braid marine rope is that because of the lack of core, it doesn’t hold its shape especially well if cleated in a cam cleat in the same spot over time. Another similar behavior is that single braids can have a tendency to “shrink” a small amount when the line is highly loaded.
A double braid, on the other hand, can most simply be described as a single braid with an independent cover on top of it. The most common cover material is polyester because of its high abrasion resistance, UV stability, and relatively low stretch characteristics. Double braid is what most people think of when they think of traditional sailing rope.
Again, specific performance can vary based on the material, but a double braid marine rope can essentially be used for any application on a sailboat, hence why it’s so popular. Double braids have a firmer hand than single braids and hold their shape better in halyard clutches or cam cleats. Additionally because of the abrasion resistant cover, most people will use a double braid in applications where the line will be on a winch for an extended period of time.
What to Learn More about the different types?
Within single braids you have two major types. The first type I would describe as standard single braids. These can be made out of polyester, polypropylene, but also could be a blended material single braid such as Dyneema blended single braid or polyester and polypropylene blended line. They tend to be made out of material that is fuzzy which further lends itself to being easy to handle and as such they make great sheets on dinghies.
The other type of single braids are high-tech single braids. They are made out of materials such as dyneema or vectran, which are high strength and low stretch line. Because of the material, high-tech single braids tend to be too slick to handle on a regular basis so they tend to be used most often on things such as standing backstays, shrouds or trapeze wires where strength is important but easy handling is not.
Within double braids you have two major types. The first is standard double braid which is a double braid polyester line. These have a polyester cover and polyester core line. In this instance the strength of the rope is shared between cover and core.
The other type of double braid is a high-tech double braid. This is sometimes referred to as a core-dependent double braid. The reason for that name is because the strength of the line is dependent on the core of the line. These lines have a high-tech core made out of Dyneema or Vectran. Because of this fact, it is common for people to strip the cover off of a
core-dependent line. People do this to reduce the weight of the line and/or to allow the line to run better through a block and tackle system for example by reducing the friction. Alternatively to create a double braid you can you can also install a cover on top of a high-tech single braid.