Is Fiber Rigging the Best Choice for a Multihull?
You’re trying to decide the best way to rig your new multihull, or you want to replace the original rigging with something more up-to-date. There are a lot of rigging technologies available these days, but are they affordable and cost-effective? We spoke with two pro riggers in New England to get a handle on the latest and most sensible standing-rigging options: Brian Fisher, of Rig Pro Southern Spars in Portsmouth, Rhode Island; and Mark Van Note, from Hall Spars, in Bristol, Rhode Island. Both have over 15 years of experience as professional sailors and riggers. We also talked to Peter Johnstone, founder and CEO of Gunboat, who builds some of the nicest production catamarans on the market today and is responsible for many of the advances in non-metallic rigging now used on production multihulls.
One of the first things we learned is that neither of the most common old-school rigging materials—wire and rod—are viable options for multihulls, except in specific low-end applications. Wire and rod are heavy, and according to Van Note, “You get a lot of cycle loading, which reduces the life of the rod. More weight, more cycle load.” Fisher agrees and adds, “Standard wire and rod rigging isn’t given a hard expiration date. Realistically, wire and end fittings can show signs of wear that can cause great concern, where a fiber shroud, headstay or backstay will look more reliable, and probably even be so.” Johnstone echoes both riggers, in an even stronger statement: “We’ve proven without a doubt that fiber is a better solution for multis. Anyone who uses steel rigging is cutting corners and short-changing the customer. The benefit of getting the weight out of the rig is huge; just the reduction of a couple of hundred pounds is dramatic, as it results in less pitching. Less pitching is more comfortable. There’s no question that the up-front cost is worth it. The overall savings over eight years is amazing.”
While high-tech fiber rigging may be more expensive than rod or wire, it also may last longer. The days of fiber having a shorter lifespan are over, thanks to improved construction techniques. The three most common materials used today are Dyneema rope, Kevlar and carbon fiber. PBO, once popular as a “fiber” rigging product, has lost traction, and, according to Fisher and Van Note, may be unavailable for standing rigging applications within the next few months.
“In the last 12 months the world has gone against PBO,” says Fisher. “It doesn’t last long, needs to be replaced on a semi-frequent basis, and any cycled shroud has to be replaced every two to three years. It’s twice the cost of Kevlar, and if you spend an extra 10 percent, you can get a carbon shroud that will last at least 10 years.”
Dyneema braided rope is the lowest-priced option, but only up to a certain size boat. Dyneema is a plastic, best described as an ultra-high-molecular-weight polyethylene (UHMWPE), composed of extremely long molecular chains, which serve to create great strength through their intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. It is also self-lubricating, has a low friction coefficient and resists abrasion. The most common commercial variant is Dynex Dux, an annealed, or “pre-stretched,” Dyneema. Another option is Mafioli’s Ultrawire. Dyneema rope is UV-resistant and need not be covered. It also resists chafe, although chafe-prone areas, such as places where sails or sheets touch the shrouds, should still be covered.
Dyneema can be used on multihulls up to about 50 feet, say our experts, and works well on multihulls because of their rig design. Monohull rigs need to be kept rigidly in column, which is hard to do within a narrow beam. Multihull rigs have much wider shroud angles, which makes it easier for fiber shrouds to support the rig. Dyneema can’t be used for diamond stays, as they need to have zero creep. It also can’t be used for roller-furling headstays, as it doesn’t have the torsional stability required. (In other words, the bottom part of the shroud will twist, but the top won’t.) If you’re trying to keep costs down, you can use rod for the diamonds (or wire on boats up to about 37 feet in length) and the headstay. If cost isn’t an issue, a specially constructed Kevlar headstay is preferable. Want to keep the Dyneema headstay? Use a regular headsail with soft hanks.
Although Dynex Dux doesn’t stretch much, it does creep, or elongate, under load, up to half a percent a year. For a good article on creep, check out sailfeed.com. The good news is that Dyneema standing rigging is easy to re-tune, as the terminations are eye splices around a thimble (or a fork at the top of a turnbuckle), which is then lashed (with smaller-diameter Dyneema) to the shroud base. To re-tune, simply tighten the lashings or the turnbuckle.
The predicted lifespan of Dyneema rigging is around six years, although you may see a slight “fuzziness” after three years. This doesn’t affect strength, it just indicates that the urethane has worn off as the shroud has aged.
Another great thing about Dyneema is that it makes for great emergency shrouds, because it stores well, lasts forever and can be quickly rigged. Both of our pro riggers say that having a spare shroud already made up (to the longest length shroud aboard) and ready to go is a great backup, even for boats using Kevlar or carbon shrouds.
The next level up is Kevlar. Kevlar has zero creep and stretches very little. Shrouds are made of a unidirectional Kevlar product with end fittings. It’s widely available, is used by many manufacturers and is not as elite as it used to be. Because Kevlar can be severely affected by UV, it’s covered with a plastic extruded jacket, which protects the fiber inside and, as an added benefit, looks nice. According to Johnstone (referring to the jackets on both Kevlar and carbon shrouds), “It takes a brazen act of stupidity to get through the cover,” and beyond that you need not worry about what’s going on beneath the jacket. “The aluminum end fittings will elongate long before the shrouds do,” says Johnstone, “so you have a visual indication of a stretched shroud.”
On the down side, the ends of a Kevlar shroud have to be finished professionally, and the lengths are not adjustable, so they must be measured correctly the first time. Also, while it may be hard to nick or cut the cover, it can happen. A shallow cut can be covered with tape as long as the fiber isn’t damaged, but if the fiber is damaged the whole shroud must be replaced. Beyond that, longevity is a hallmark of many of the Kevlar rigs Van Note has refitted, including some Gunboat 62s, the oldest boats in the Gunboat lineup. “They have Kevlar rigging, which we didn’t have to replace,” says Van Note. “They do require a serious inspection after four years, and we’re seeing a six- to eight-year lifetime depending on mileage.”
Kevlar can also be used on multihulls with carbon rigging. “We use Kevlar forestays and cap shrouds because they have a little stretch, which isn’t a bad thing,” says Johnstone. “It’s nice to have a little stretch on an all-carbon boat to absorb some of the loading you encounter in a sloppy leftover sea state.”
As for carbon itself, it currently represents the high end of the standing rigging market, costing 10 percent more than PBO, which is, in turn, twice the price of Kevlar. The most widely used carbon rigging products are rigid form EC6 Carbon from Composite Rigging, which is constructed from a bundle of small-diameter pultruded carbon-fiber rods; Seamless Carbon Rigging (SCR 35), a solid carbon-fiber rod from Hall; and Carbo-Link, which is constructed from a carbon-fiber polymer matrix system.
Compared to all other standing rigging, carbon shrouds have the smallest diameter (less windage) and the least amount of stretch. Carbon isn’t susceptible to UV, but the epoxy resin that holds the material together is, so all commonly used carbon rigging comes with some type of covering applied during the manufacturing process, usually an overbraid of polyester or Dyneema, to provide protection as needed. As with Kevlar, carbon rigging is manufactured to length, and most use carbon-wrapped titanium end fittings. Although there were some end-fitting problems with carbon early on, these have since been resolved, so that longevity and cost of ownership has become a selling point for this material as well.
“In 2005 our Gunboat 45 Cream was the first production boat in the world to cross the Atlantic with carbon rigging,” says Johnstone. “It’s still going strong after eight years, and we think EC6 likely has an indefinite service life. We see no indications of a need to replace that carbon rigging. We’ve already seen 80,000-mile life with no issues, and I think we can easily do 150,000 miles. Rod rigging will last 20,000 miles, tops.”
Johnstone’s comment about the longevity of carbon rigging may well elicit screeches of horror from manufacturers, but the point is all three types of standing rigging now have proven track records. As a result, there is a large database that you and your builder or rigger can consult when deciding what is best for your boat and your budget.