Faster Furlers Technology Goes Continuous

Headsail hanks are proven technology, ironically finding favor once again on a few of the Volvo 70s. But there's another way of attaching and flying headsails, and for simplifying things on the foredeck. We're talking continuous-line roller furlers, hardware once exclusive to singlehanded and crewed ocean racers, America's Cup boats, and large multihulls. In textbook trickle-down fashion, these simple (in concept) furling systems have found widespread applications on smaller boats with usage on loose-

luff reaching sails like Code Zeros and staysails, asymmetric spinnakers, and more recently, upwind sails as well.

While the ultimate convenience of any roller-furling headsail is a given, for racing sailors there are a number of disadvantages with traditional drum-and-foil furlers—line snags in the drum, extra weight at the bow (contributing to pitching), and a less-than-perfect headsail shape as a result of the tack being attached at the top of the drum.

KARVER CONTINUOUS-LINE furlers on the Open 60 Bonduelle show the versatility of this new furling technology.

But today's continuous-line furlers are lightweight, most require no luff foil, the low-profile "drums" (spools) can be mounted closer to the deck for a better sail shape, and with furling units permanently attached, certain sails can be quickly deployed or stricken when the weather surprises.

From a need came a solution

A traditional drum-furling system, with a single furling line running aft from the drum, rolls the sail around the luff foil (or tube, depending on the make). This system works well for upwind headsails, especially for reefing, but when offshore racers in the Open 60 class began experimenting with drum furlers for their offwind headsails (winding them directly around the sail's luff wire), they found that the required length of furling line varied. When there was more wind, it would take more turns of the furling drum to roll the sail properly. From this handicap, the continuous-line furler was developed. The

Continuous Line Furler

HARKEN CURRENTLY OFFERS a Code Zero continuous-line furler for reaching sails; the smallest unit is designed for boats in the 20- to 30 foot range.

Harken Continuous Furler

FACNOR HAS TWO models of continuous-line furlers; the RC (above) and the SDG. The RC furlers work in tandem with a luff foil (permitting upwind headsails and reefing). The SDG units (not shown) are meant for free-flying sails.

HARKEN CURRENTLY OFFERS a Code Zero continuous-line furler for reaching sails; the smallest unit is designed for boats in the 20- to 30 foot range.

concept is simple: a continuous line is led forward, around a large-diameter spool, and back to the cockpit.

It's not perfect. The furling line on the spool must have sufficient grip to roll the sail. Another disadvantage is having two furling lines running aft (rather than one as with drum furlers). But once the sail is furled, the halyard can be released, the sail dropped to the deck, disconnected from the furler's spool, and then stowed as one long "sausage." Think of the time saved not flaking between sail changes. There's also the consideration of getting the right amount of tension when the sail is flying, and for this, there's typically a 2-to-1 purchase somewhere in the system, either aloft at the halyard swivel, or at the base of the furler.

Several manufacturers currently offer continuous-line furlers—Equiplite, Fac-nor, Harken, Karver, Precourt, and Profurl.

The majority of them offer units designed to work with free-luff sails, such as staysails and Code Zero-type sails. At press time, Facnor was the only manufacturer offering a continuous-line furler designed specifically for upwind headsails. These models make up the Facnor RC line. The system uses an aluminum extrusion as the luff foil. The foil itself rotates around the headstay as the sail is rolled. John Killeen, sales manager for Facnor USA (Charleston Spar), which imports the Facnor units from France, says continuous-line furlers like these are likely the future. "I wouldn't say the days of the drum furler are numbered," says Killeen. "There are guys who have always had a drum furler and it has always worked."

Whether one uses a continuous-line furler with a luff foil like the RC, or with a free flying sail, the advantage, says Killeen, is that the larger diameter of the spool gives greater leverage than a drum furler. He does, however, offer one caveat: "The trick, if you can call it that, for a continuous-line furler is that the drum is designed to use a specific, constant-diameter [furling] line. The furling line is made using a splice that maintains the line's diameter and strength. People are now working on a better splice."

Facnor's continuous-line furler for Code

FACNOR HAS TWO models of continuous-line furlers; the RC (above) and the SDG. The RC furlers work in tandem with a luff foil (permitting upwind headsails and reefing). The SDG units (not shown) are meant for free-flying sails.

Zero and gennaker applications is the Fac-nor SDG model—which is used on a wide range of boats, from 21-foot Mini Transat designs to a Baltic 147. On the larger SDG units, the furling line's entry and exit points feature funnel-shaped openings that provide a fair lead into and out of the line driver. The intricate machining of the aluminum spool, says Killeen, contributes to the high cost of these units, but the engineering of the machining influences how the spool grips the furling line when the system is put under load.

Used Headsails
PROFURL'S LARGER NEC continuous-line furling units are designed for boats in the 50-foot range. The smallest NEC model works with light headsails up to 350 sq.ft. in area.
Small Continous Line Furlers

EQUIPLITE UNITS ARE used for free-luff sails on boats 30 to 100 feet. All furlers, including the 10 FS (above, for 60 footers and larger) use soft loops, at the drum and swivels, which contributes to its light weight (the 10 FS weighs 3 lbs.)

The SDG range goes from its smallest furler, the SDG 1000 PC (engineered for 20 to 35-footers, and a maximum sail area of 430 sq. ft.) to the SDG 8000 PC (60-footers on up; max. sail area 3,444 sq. ft.). Everything else above the 8000 is a custom unit.

Last year, Euro Marine Trading, based in Newport, R.I., began carrying the French-built Karver line of continuous-line furlers, lightweight marvels of engineering that, according to EMT's Katie Ambach, can be used for small jibs to asymmetric spinnakers. Karver makes furlers with working loads ranging from 1,650 pounds (their model KF0.75, which is used on smaller sportboats and multi-hulls for jib and spinnaker applications), to its KF12, which has a working load of 26,000 pounds). The KF0.75 weighs slightly more than 10 ounces, and the 12T weighs in at nearly 8 pounds. Karver's KF1 units are widely used on TP 52 staysails, and the KF5 for TP 52 Code Zeros.

Karver furlers have been the popular choice among elite racers in Europe for several years, and several engineering details demonstrate how refined these units are. For example, the design allows the furling line to be quickly fed onto the spool (rather than taking the unit apart). A protective rubber ring around the spool protects it from being damaged or bent, which would prevent it from rotating properly. These furlers tend to remain at tached to the sail when it's dragged be-lowdecks, so the ring also protects a boat's deck and interior finish.

ProFurl, another French manufacturer, offers two types of continuous-line furlers. One is its NEC model, which has titanium components, and an optional, integral 2-to-1 swivel fitting at the head, and the other is its NEC ST, which they describe as a "Stayfurler." With the NEC ST, the existing rod or cable stay is replaced by a Kevlar line, which makes the furling system itself a structural part of the rigging. This is in contrast to most other systems in which the furling system is not structural, fitting over the stay. ProFurl claims the benefits include weight savings and a longer luff length. The Stayfurler system is available with either drum (with a single line) or continuous-line furling.

ProFurl's continuous-line luff furlers will fit a wide range of boats, from 27 feet to 70 feet for heavy sails, and 30 to 120 feet for light sails.

Harken has one continuous-line furler, its Code Zero Furler, which is designed only for free-flying, reaching sails. The Unit 00, which weighs less than a pound,

Continuous Line Furler

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  • SOL
    What sails can go on a continuous furler?
    27 days ago

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