The time-honored way to attach a boat to a mooring anchor is with chain. The primary advantages to chain, of course, are strength and abrasion resistance. The major downside to chain is also well-known: as a metal, it corrodes and must be replaced. What about using a length of high-strength line? That is the approach that Yale Cordage is suggesting via a product called Uniline.
Yale Cordage has a long-term installation of Uniline that it can point to as an example of how well this line does as a mooring line. Twenty-five years ago, they attached Uniline hawsers to a dock structure at Strouts Point Wharf in South Freeport, Maine. The Uniline has performed solidly through 25 seasons. On May 16, Yale replaced one of the hawsers with plans to perform destructive testing on the line. By breaking it and looking at its core, Yale will be able to see how well it performed after 25 years of exposure to salt water, mud, silt and attack from mussels and sea slugs.
According to Yale, what makes Uniline work as a mooring line is the way it is constructed. The core is a parallel, polyester line that is run through a latex bath and then wrapped in neoprene. This package is then protected by a braided polyester cover that is coated in urethane. Finally, the line is then baked in an oven, causing the latex and neoprene to fuse into the fibers of the core. According to Yale Cordage, “Uniline is the toughest conventional stringing line you can buy and minimizes the elasticity and stretchiness seen in polyester ropes. Ropes removed from machines having seen 20 years of service regularly test at 75 percent of the original strength and above.”
The key to the line’s longevity is the waterproof core, according to Yale sales manager Skip Yale. “No water or marine life can get into the core,” Yale said. Yale added that the waterproof core of Uniline early on caught the eye of the power utility industry. Uniline can be used in wet conditions near power lines. Since water won’t get into the core, the rope stays nonconductive. Cable laying ships also use it as a grappling line, since it won’t become saturated with water and grow heavy. Another version of Uniline called Unitrex XS Max Wear uses a Spectra core instead of polyester. This makes the line stronger and lighter, a big plus for cable laying operations which can need to carry thousands of feet of grappling line.
Yale said Uniline is being used in dock systems in the Persian Gulf states of the United Arab Emirates in lieu of chain. Which brings us back to using Uniline instead of chain on a mooring. A mooring setup is inherently different from the ground tackle your voyaging boat carries for anchoring, of course. In the case of anchoring, it is an excellent idea to use a sizeable length of chain attached to the anchor for abrasion resistance. Some voyagers even carry an all-chain rode. A mooring is different, however. It employs a mooring ball to help keep at least some of the chain attached to the anchor or sinker up off the bottom. So in the case of a mooring where abrasion isn’t a factor, but resistance to corrosion and longevity is, a product like Uniline can carry a potential benefit in long life.
The 25-year-old installation in South Freeport at Strouts Point seems to indicate that long life is a clear benefit of a product like Uniline. Some of the mooring lines at Strouts Point were led ashore to a wooden bulkhead. These lines were tied to pilings at the bulkhead’s base. At low tide, the Uniline hawsers were lying in a soupy mixture of thick muck, stones and marine life. But some serious sawing was required to cut away the 25-year knots. Even though the line sat in this abrasive mixture, it appeared strong as ever. That ability to keep out foreign matter helps the line stay strong. “Even small pieces of dirt or sand that get into the core of a rope can cut the fibers over time as the line moves with tide,” Yale said. “By keeping everything out of the core, the line stays strong.”
So perhaps now that it has proved itself after its lengthy trial at Strouts Point, products like Uniline will be used more instead of chain in mooring applications. A Uniline-based mooring is a larger upfront cost, but at 20 or more years of service, it likely will be cheaper in the long run compared to chain. While many harbor masters still require the use of chain for mooring systems, some, such as York, Maine, have given the OK to the use of synthetic line.
Another company that offers a synthetic line mooring system is Vermont-based Conservation Anchoring Technology, which has a mooring package that uses an elastic mooring system with a shortened scope requirement in which the components are floated off the sea bottom.