Selecting Line for Running Rigging
By Tom Burden, Last updated 5/8/2018
Selecting the right running rigging for your sailboat can be a challenge. There are a lot of choices, and your selection is often more a matter of taste than function. Competing manufacturers offer similar products, like Endura Braid, WarpSpeed II and XLS Extra. How do you decide which line is best for your application?
One way is to check our Line Selection Guide, below. We have grouped some line models by application, with input from the pros at West Marine Rigging. Below is a more detailed and technical look at line construction types and line fibers.
Line selection guide
Our Selection of running rigging line is covered in this handy, downloadable guide.
Consider the construction of the line
We’ve divided our selection by construction type. Some configurations make better halyards, mainsheets or vangs, for example. You have three styles to choose from:
- Single braid: Supple, flexible construction absorbs twist and doesn’t kink. There are two styles: performance single braid, made from fibers with very low stretch, designed to handle extreme loads, or blended/polyester single braid, soft and easy to grip, built for sheets and other hand-adjusted control lines.
- Double braid: A braided core inside a braided cover results in a strong, durable, smooth-running line that’s easy to handle.
- Three strand: Made of three strands twisted, or laid, clockwise in a “right hand lay” with the fibers in each lay twisted to the left. Favored for traditional boats, but best for anchoring, towlines and mooring because it stretches a lot more that braid.
Below are some of the styles of line, grouped by construction and type of fiber, which we’ll discuss below, and some suggested applications for each one:
How strong does the line need to be?
Greater line holding working loads are achieved by increasing the diameter of the line, or by using a line of the same diameter that’s made from stronger fibers. 3mm V-12 single braid has a Breaking Strength of 2,100 pounds. 3mm HTS-90 single braid has a Breaking Strength of 3,400 pounds. Same diameter—lots more strength. Match the diameter of the line to the application. If necessary, consider asking West Marine Rigging to customize the line, for example, sleeving the line with an Abrasion-Resistant Cover in the rope clutching area to increase the diameter and line-holding performance. Consider that hand-adjusted lines feel most comfortable to grip at about 5/16" to 3/8" diameter.
Do you want to color-code your line?
Many lines include cores and covers of matching color, so you can strip the cover to reduce size and weight, and still know which halyard to clip onto your headsail.
Consider the “hand” or feel of the line
Some lines, like Sta-Set, have a smooth surface that runs easily through a purchase system. Others, like WarpSpeed II or Endura Braid, have a knobby texture that’s “grippy” and easy to hold. Soft, flexible lines such as Salsa use spun fibers, so they’re comfortable to hold in your hand all day while trimming a mainsail. Sta-Set X is a stiffer line, great for halyards, not so good for frequent trimming.
How much stretch are you able to tolerate?
In general, racing sailors who fly sails that don’t stretch need low-stretch, high modulus line. You pay more for performance and tolerate lower durability and less resistance to UV light exposure. Family cruisers or daysailers want long-lasting, UV resistant lines. With stretchier Dacron sails, you don’t need exotic high-tech line.
The amount of acceptable stretch also depends on the application, for both racers and cruisers. Genoa sheets and other frequently adjusted hand-controlled lines can tolerate more stretch. A halyard for a roller-furling jib that’s left in place all season requires a rope with lower stretch.
Stretch is determined by the type of fiber a rope is made from, as well as its construction. Knowing the fibers and what they do best is the key to selecting line that meets your needs at the lowest cost.
Line fibers and their characteristics
Nylon: The first synthetic fiber used in line, nylon is almost never used in running rigging, but excels for anchoring and docking, where its stretch (up to 15%) helps to absorb shocks. Nylon is durable, with excellent internal and surface resistance to abrasion, a high strength to weight ratio, and a Specific Gravity of 1.14. It does absorb water and shrink, with a loss of 10%-15% of its strength.
Polyester: Stretchier than newer fibers, it holds color well and has great abrasion resistance. It’s an excellent cover for double braid lines, protecting low-stretch cores from UV radiation and chafe. Polyester double braid works great for frequently adjusted lines, like main and jib sheets, or moderately loaded control lines. It is very flexible and easy to handle, and is still the line of choice for most applications on cruisers and club racers. Specific Gravity is 1.38, so it does not float.
Polypropylene: A light, relatively inexpensive, relatively stretchy fiber, polypropylene is frequently blended with other fibers like Dyneema to add bulk for easy handling. Samson uses this combination in their XLS Extra-T braid, which is stronger and lighter than polyester, but less costly than 100% Dyneema. Polypropylene floats and doesn’t absorb water, but has poor UV resistance. Its stretch is similar to polyester, so it works well for sheets, especially light-air spinnaker sheets, dinghy main and jib sheets, and other frequently adjusted control lines. Durability is not its strong suit, so more frequent replacement is needed.
Dyneema (High-Modulus Polyethylene/HMPE): Several patented variations of this fiber have slightly different characteristics, but Spectra-Dyneema-HMPE has the highest strength-to-weight ratio, low stretch, and impressive maximum working loads. Very slippery with good hand, but poor knot-holding ability and a low melting point (300°F). Does not absorb water, but it will experience gradual “creep” or permanent elongation under sustained static load. Dyneema is a good core upgrade from polyester double braid, with almost no stretch.
Often used uncovered, or with a polyester cover where it encounters a cleat or the drum of a winch. Great in multi-part purchase systems, or for replacing 7 x 19 wire in trapeze lines. A very popular line with excellent longevity; it is also light, so it floats.
Other Articles and Videos on Running and Standing Rigging
Newest, strongest, lowest stretch, and with nearly zero creep are Dyneema lines made from a variant called SK-90. It stretches 10-15% less than the most common type of Dyneema, SK-75, and is also 10-15% stronger. New England Ropes’ HTS-90 and Dinghy Star (from FSE Robline) are two ropes made with this fiber.
Vectran (Liquid Crystal Polymer):Vectran has almost no stretch, no creep, and absorbs little water. It works reliably at a high percentage of its breaking strength, so it’s great for highly loaded applications. Like Technora, Vectran is among the strongest core materials available. UV resistance and durability are moderate. Often used for upwind sail halyards under static loads, like permanently hoisted roller-furling headsails. Used both stripped and covered, for highly loaded purchase systems and travelers, and other no-stretch applications.
Technora (Aramid): Very low stretch and no creep. Like Kevlar, Technora has poor internal abrasion tolerance, fair chafe resistance, and is damaged by UV light. Blending with another fiber, like Dyneema SK-78 in the core of T-900 line, helps reduce the durability problems associated with Technora, and lets its strengths shine. Technora needs protection with a polyester cover, or coating on the core, if stripped.
PBO (Zylon): PBO (polybenzoxazole) is a ridged isotropic crystal polymer with incredible tensile strength, with best strength and stretch characteristics of any available fiber. PBO has low internal abrasion resistance and degrades rapidly when exposed to UV radiation. Moisture also damages PBO, creating a 15% loss of strength when it’s exposed to water, so it needs to be completely sealed from the elements. It’s extremely expensive and only used at the highest level of Grand Prix sailing.