Four Small Boat PVC-Foil Furlers
The development of reliable headsail furling must rank high on any list of devices that have significantly changed the way boats are sailed in the past two decades. Hanked-on sails, while having certain advantages, are disappearing in favor of roller furling jibs and genoas. Furlers keep the crew off the bow and reduce time spent sail handling. And thanks to improved designs, the sight of a tattered furling genoa flogging itself to death also is disappearing. Jams, once the bane of furlers, are much less frequent.
Practical Sailor has tracked the evolution of headsail furling for many years. In 1988 we undertook a comprehensive evaluation of available models and followed that in the May 15 and June 15, 1995 issues with a follow-up evaluation backed by a reader survey, which showed marked improvement in performance, reliability and customer satisfaction. At that time, 77% of all survey respondents said they would buy the same furler again, led by Cruising Design Inc. (CDI) and Famet (an older system) at 100%, followed by Profurl, Schaefer, Harken and Furlex.
In the November 15, 1997 issue, we again updated the group, highlighting the new Hood SeaFurl 5 and redesigned Furlex.
The Small Boat Market
Average boat size in the 1995 reader survey was 32'. The number was drawn down a bit by the 25' average size of boats equipped with CDI Flexible Furlers. Indeed, CDI has made a living selling furlers to owners of smaller boats, especially so-called “trailer sailers.” And while the other major manufacturers, such as Profurl, Harken, Hood, Furlex and Schaefer, have long offered their standard furlers in small boat sizes, and even some simplified models such as Hood’s Line Drive, none tried seriously to compete with CDI’s PVC luff extrusion.
The advantages of the plastic luff are several. First, unlike rigid aluminum luff extrusions, which are shipped in lengths of about 6', and must be connected with splices or link plates and fasteners, pliable plastic extrusions are one piece and require no assembly. More and more boat owners are buying furlers from mail-order houses and doing the installation themselves. Secondly, the PVC can take a fair amount of abuse and is not as easily dented as rigid aluminum extrusions, an important consideration for any owner when stepping and unstepping the mast. It is of particular concern to owners of trailerable sailboats who handle the mast a lot. Thirdly, cost is less, making furling more affordable for owners of small boats.
Plastic won’t corrode, of course, but is subject to ultraviolet attack. Nevertheless, the addition of UV inhibitors should give them adequate life spans.
Three years ago, CDI’s dominance seemed about to change when Harken announced its first Heli-Foil, which used a PVC luff extrusion with an inner polypropylene sleeve over a braided stainless steel core. There were problems with it, however, and they took a long time to solve. Undaunted, Harken persisted and the new Heli-Foil is now available.
Not to be outdone, Hood Yacht Systems introduced its economical Sea Flex and Schaefer developed its SnapFurl.
We obtained furler kit packages of each, roughly sized for boats up to 24' with maximum headstay lengths of about 30' and maximum turnbuckle pin size of about 3/8". Exact specifications are given in the table on p. 14.
All four foils come tightly coiled with warnings not to start cutting the bindings willy-nilly. There is a lot of energy packed in these foils that could cause an injury if handled carelessly. Most tell you to make sure the air temperature is at least 70°F and to uncoil outdoors; if it’s colder than 70°F, warm the foil indoors. CDI urges installers to uncoil within 24 hours of receipt so that the foil doesn’t take too much of a set. Observe directions regarding which end of the coil to start cutting free first as there will be a feeder near one end.
While all are flexible, they should be stored flat in the off season (assuming you’ve unstepped the mast). Allowing them to droop deeply also can cause them to take a set. They can be removed and coiled again, but Harken cautions that repeated tight coiling can reduce the life of the foil.
Because PVC is temperature sensitive, the manufacturers warn against exposing the luff extrusion to high heat—around 130°F-140°F. Such temperatures might be found under a boat cover in hot climates.
Presumably to reduce costs, only one of the four offers a line guide attached to the drum; that’s Schaefer and it’s a $23 option. This makes proper placement of the first lead block critical so that the line doesn’t chafe on the cage as it exits the drum.
The luff tape sewn to the jib or genoa will be #5 for Harken, Hood and Schaefer, #6 for the CDI Flexible Furler 2.
Ease of furling is affected most by the bearing surfaces, but also by the ratio of the foil diameter to the drum diameter; after all, the difference in the two is what gives you a mechanical advantage. The higher the ratio, the more advantage. We measured all four and developed these approximate ratios: Harken 2.5, Schaefer 2.14, Hood 1.65, and CDI 1.45.
Installation for any system will be easiest with the mast down but because you won’t have to completely remove the headstay for shortening the wire it is possible to do with the mast stepped. Nevertheless, you will have to unfasten the forestay from the stem to slide on the luff extrusion and torque tube/furling drum. Take a halyard forward to a strong attachment on deck, such as a toerail, to hold the mast while you work.
All four systems are fairly simple, with few pieces. The average do-it-yourselfer should be able to install his or her own with basic tools. The one critical job is cutting the luff extrusion to the right length. All manuals give explicit instructions—measure twice, or three times, and cut once.
Halyard restrainers may be necessary with any furler (except CDI with its internal halyard) if the angle of the halyard to the upper swivel is less than about 5°. A restrainer is a simple fitting that is screwed to the mast and through which the halyard is led to increase the angle. This is to prevent “halyard wrap,” in which the length of exposed halyard between the mast and the swivel wraps around the headstay as the sail is furled. You don’t want this!
Compared to larger boat furlers, these—especially the CDI and Sea Flex—are simpler and lack such features as integral adjusters.
CDI Flexible Furler 2
Joe Dahman bought CDI in 1984. At that time, Dahman said CDI was building furlers “on the floor” with metal luff extrusions and plastic links, which had a tendency to break. His first idea was to switch the materials. In the course of investigating and testing plastics, he came upon the idea of making the luff a continuous length, thereby omitting the link plates that trouble nearly every furler. If made of the right material, this single-piece luff extrusion would be much less resistant to damage when raising and lowering the spar, and enable CDI to ship the extrusion coiled in a box. He sold his first Flexible Furler in 1987 and since has delivered more than 10,000. He holds a patent on the flexible luff for which Schaefer is licensed by CDI; Harken and Hood are not.
Price is $515 list, and discounts through Defender Industries (800/628-8225) to about $300.
Unlike most furlers, the CDI uses an internal halyard, which eliminates the halyard swivel at the masthead. This places the furler in compression, not tension, and so the bearing is under less load. The halyard runs up inside one of two opposing grooves in the luff extrusion, through the Halyard Top Fitting, then back down to the head of the sail. The luff is not tensioned by this halyard, however, but by a short length of 1/8" line seized in two to three parts between the tack of the sail and the downhaul shackle on the spool flange.
The standard furler comes with a UHMW polyethylene bushing as the bearing surface, though an optional bearing race is offered for $70 list. But instead of lots of small bearings, the FF2 model has seven 1/2" Torlon bearings in a small race. Dahman says that a few large bearings work better and are more reliable than lots of small bearings, which have a greater tendency to get hung up on dirt or other debris in the race. The bearing kit is available as a retrofit; you can do the job in about five minutes.
Dahman has refined the system over the years, adding a few parts here and there. In 1990 a thrust bearing was added and in 1994 he replaced the aluminum cup or cage with stainless steel. For 2000, he enlarged the center hole to accept 5/16" turnbuckles, crimped a ferrule to the halyard to secure the core to the cover where the line has been decored, and uses a larger 1/4" braided halyard. Because the 42" x 40" coil size of the FF2 requires some straightening of the luff, CDI now offers a 6' large hoop that is slightly less expensive but costs $60 to ship air freight. It does not require straightening.
There is no stainless feeder, like the Schaefer and Harken, just a slot in the foil, same as the Hood Sea Flex.
The manual with photos and drawings is adequate, if a slight bit confusing to follow at a few points.
The 3/16" furling line is small to handle; we’d upgrade to1/4".
In answer to criticisms that plastic luffs twist more than an aluminum luff, Dahman counters that aluminum twists more than people realize, principally at the section links, and that some twist is beneficial in spilling air in gusts.
CDI makes eight sizes of the Flexible Furler, from the FF1 to FF8, which is for maximum headstay lengths of 47', 5/16" wire and 1/2" pin size.
CDI offers a lifetime warranty to the original buyer.
Bottom Line: The least expensive of the four, the Flexible Furler is simple and has a good track record with PS readers. It would be our choice among non-ball bearing models.
Schaefer Marine has been making headsail furlers longer than just about any other company, dating to the 1970s when it made simple upper and lower bearing swivels for use with wire luff headsails.
Schaefer entered the modern era with its 1000, 2000, 3000 line in the early 1990s. It has since refined those models and more recently added its SnapFurl small-boat furler. It discounts to about $365.
SnapFurl’s single-groove foil is made of round, extruded PVC in two parts that snap together and interlock, which probably helps it resist twisting. The opposing forces of this joint also help the PVC straighten itself; Schaefer’s Fred Cook nevertheless recommends laying the PVC out in the warm sun for a while before assembly. The foil coils in a 34-1/2" box.
The torque tube and drum are also injection molded plastic, a “long-grain nylon composite with UV inhibitors.” Bearings are Torlon, with two races in both the head swivel and drum. The two-part cage is stainless steel as is the sail feeder. The fasteners are captive so they won’t fall out if you have to disassemble the feeder.
The six-page manual with drawings is adequate.
Cook said that his company’s intent was to design a furler that was price competitive with CDI but retained some of the features of its other furlers, such as Torlon ball bearings and the ability to fit over the existing turnbuckle. It was also advantageous to use the same foil material as their Tuff Luff racing foil. They also wanted to price the SnapFurl lower than the Harken 00 Heli-Foil. About half of all SnapFurls are sold in Europe—France, England and Germany—Cook said.
Bottom Line: Innovative snap-together foil; stainless cage, feeder and aluminum upper swivel, and ball bearings make this a premium system at a low price.
Harken 00 Heli-Foil
The Heli-Foil uses a PVC foil but with a polypropylene interior for what it says is an improved bearing surface. The PVC is cored with braided stainless steel for greater torsional rigidity. Of the four examined, Harken’s looks like it will resist twisting the best. Also, Harken’s foil is the only one of the four that has double grooves; this enables you to hoist a new sail before completely dousing and removing the existing sail.
With racers in mind, the two-part drum also may be removed as well as the halyard swivel, though the latter is probably more trouble than most owners will want to endure (you must rig a temporary headstay and disconnect the turnbuckle).
Discount price is about $700.
The drum is made of plastic while the cage, torque tube and halyard swivel are black anodized aluminum. Double races of Torlon bearings are used in each bearing. A torque tube key locks the foil inside the torque tube. A special clevis pin is required for your turnbuckle, available from Harken when you order your furler. It is longer than your existing clevis pin and locks the lower bearing fork to the turnbuckle and stem fitting.
Like Schaefer, Harken manufactures a complete line of accessory hardware.
Harken’s manual is excellent, with clear step-by-step instructions and accompanying photographs—the best of the group.
Bottom Line: The most expensive of the four, the Harken 00 Heli-Foil is also the most sophisticated with its stainless braid-reinforced PVC foil and aluminum parts; it’s also more versatile, should removing the drum for racing be of interest. Ideal for a J/80 or F/24.
Hood Sea Flex
Sea Flex’s one-piece PVC foil is flat, like the CDI Flexible Furler, but has only one slot as it does not employ an internal halyard. It is reinforced with a 1 x 19 stainless wire running its length. This is supposed to help keep the foil from twisting but probably won’t be as effective as Harken’s larger diameter reinforcement.
The torque tube and upper swivel bearing are injection molded parts. The upper bearing has two races of Torlon ball bearings. The lower bearing is simply the stainless steel fork (which attaches to the turnbuckle with a clevis pin) turning inside a Teflon-impregnated Delrin insert in molded grooves in the lower end of the torque tube. Obviously this isn’t going to be as friction-free as one with ball bearings. However, it turned fairly easy…until we assembled the cage.
Like Harken, Hood’s lower bearing fork fits over the turnbuckle so that the clevis pin locks both to the stem fitting. On CDI and Schaefer, the pin simply passes through the slot in the turnbuckle body, which could cause it to unthread if sturdy cotter pins are not used to prevent the studs from turning in the body.
The fork has a second set of holes in case one wants to raise the unit with link plates.
The torque tube is cast in two pieces with threaded brass inserts for the six fasteners. The top and bottom of the drum are also black plastic and snap into grooves in the torque tube. They are easily removable for racing. The cage looks just like those on the SeaFurl 5; it is stainless steel. Assembly is quick, intuitive and actually quite clever.
The cage is held stationary by two pins snapped into the fork and also fits into grooves in the top and bottom cage parts. Thus, the plastic top and bottom cage parts revolve around the stainless, creating what we felt was excessive friction—certainly the most of the four furlers examined. When we queried Hood Yacht Systems’ Mike Haber, he admitted it turns roughly at first, but said that as the system wears in during actual use, there will be no problems furling.
Like the CDI, there is no metal feeder, just a slot cut in the foil.
The 8-page manual has drawings and is adequate.
Bottom Line: Hood Yacht System’s aim was to price the Sea Furl close to the CDI FF2, and it has done that—$311 at discount. While cleverly conceived, friction is a concern.
Between the two least expensive—Hood and CDI—the latter has a bushing bearing at the bottom, with optional ball bearings. Hood does not. In addition, CDI’s internal halyard reduces friction. While we like Hood’s clever design, the CDI is a bit less money and has a long track record of customer satisfaction. At least until more experience is gained with the Sea Flex, we’d go with CDI. Owners of the Sea Flex are invited to give us their comments.
Schaefer prices out not much above CDI and Hood. It has just about everything Harken does—ball bearings top and bottom, many stainless parts, and what appears to be a good two-part luff extrusion—at a much lower price. It rates a Best Buy, hands down.
The Harken Heli-Foil is top quality and its split drum and excellent double-groove foil makes it the clear choice for performance sailors.
Contacts- CDI, 100 Cummings Center, Suite 106F, Beverly, MA 01915-3056; 978/922-5936; www.sailcdi.com. Harken Yacht Equipment, 1251 E. Wisconsin Ave., Pewaukee, WI 53072; 262/691-3320; www.harken.com. Hood Yacht Systems, 7712 Cheri Ct., Tampa, FL 33634; 813/885-2182; www.pompanette.com. Schaefer Marine, 158 Duchaine Blvd., New Bedford, MA 02745-1293; 508/995-9511; www.schaefermarine.com