Seldén GX vs Profurl Spinex vs Harken Reflex vs Facnor FX+: which top-down gennaker furler fits your boat?

We compared the four Code 0 systems side by side a few months back. Ask the same question about a gennaker furler and the shortlist looks similar on paper, Seldén, Profurl, Harken, Facnor, but the systems themselves work differently under the hood, because a free-flying asymmetric sail furls from the head down instead of the tack up. If you already know why that matters, skip ahead. If you don't, our top-down vs bottom-up furler guide covers the mechanics. This article is about which of the four actual products, Seldén GX, Profurl Spinex, Harken Reflex Gennaker or Facnor Fast FX+, fits the boat you're standing on right now.

What actually separates these four systems before you look at the price tag

All four do the same basic job: a drum at the bottom, a swivel at the top, an anti-torsion cable running between them. The differences that matter show up when the sail is halfway furled and the wind gusts.

• Seldén GX uses a metal tooth grip on the drum and a Torlon ball bearing tack ring, sold as a complete kit with the AT-cable and halyard swivel included. You size it by sail area first, not boat length, which makes sense for a free-flying sail where drag scales with area rather than LOA.
• Profurl Spinex runs on what Profurl calls Sail Bearing Technology, a bearing arrangement built to resist jamming under load. The Spinex Ratchet adds a FurlAssist ratchet that locks the drum between pulls so the sail cannot back off while you reposition your hands on the line. Pull sharply to release it. It works in both directions, so you do not need to think about which way you last wound it.
• Harken Reflex uses a braided stainless cable over a textile core rather than a solid rod, which Harken says transmits torque at lower halyard loads than a conventional cable. The modular T-fitting is the real party trick: disconnect one sail with a spring-loaded pin and clip on a different one in seconds, useful if you run a gennaker and a Code 0 off the same tack point.
• Facnor Fast FX+ is built around an anti-twist line system and quick-release pins, and covers the widest capacity range of the four, 900 kg to 7000 kg SWL for boats from 20 to 70 feet. That range is why you see it on everything from a 32-foot cruiser to a 65-foot performance cat.

Seldén GX: sized by sail area, not by your boat's LOA

The GX kit is a drum, a halyard swivel and Seldén's AT-cable in one box, which keeps the compatibility question simple: you are not hunting for a separately-sold cable that matches the drum. On the configurator you pick your maximum sail area first, then the available lengths and specs narrow down from there. That flow catches a mistake we see often at 123Furling: sailors sizing a gennaker furler off their forestay length like they would a genoa furler, when the number that actually matters is the area of the biggest asymmetric sail they intend to fly through it, not the boat's overall length.

The Seldén GX Furling System starts at €987 for the smallest configuration and is the cheapest of the four to get into, useful if you are outfitting a 32 to 40-foot cruiser with a single Code 0-sized gennaker and do not need the ratchet or the multi-sail swap.

Profurl Spinex and Spinex Ratchet: the system built around not letting go

Profurl's pitch for the Spinex is safe, easy, one-handed operation, and the spec range backs that up: boats from 8 metres to over 20 metres, MWL from 900 kg to 8000 kg, drum diameters from Ø120 mm to Ø250 mm depending on the model, and reefing line from 8 mm to 10 mm. That is the broadest drum and line range of the four, which is why Profurl can put the same basic architecture on a 27-footer's cruising chute and a 65-footer's A2.

Where the Spinex Ratchet earns its higher price is the FurlAssist mechanism. On a plain Spinex, if you ease off the furling line mid-roll, even briefly, the sail can back off a few degrees and you lose the wrap you already had. The ratchet locks the drum between pulls so that does not happen, which matters more than it sounds like when you are furling short-handed in a building breeze and need a hand free for the winch. The Profurl Spinex Ratchet costs roughly €130 more than the standard Profurl Spinex, which is a small premium for a feature that mostly matters when you are sailing alone.

Harken Reflex: one drive unit, several sails

The Reflex line splits into three fixed unit sizes rather than a continuous size-by-sail-area curve like the GX or Spinex. Unit 1 covers 7.5 to 11-metre boats up to a 1.5-tonne MWL and 112 m² of sail. Unit 2 moves that to 10 to 14 metres, 2.5 tonnes and 168 m². Unit 3 tops out at 12 to 17.7 metres, 4.5 tonnes and 223 m². If your boat sits right at the edge of two brackets, size up, not down, the unit rating is a working limit, not a burst limit, and gennakers get sailed in more breeze than the brochure photo suggests.

The feature that sets the Harken Reflex Furling Gennaker System apart is the quick-release T-fitting. One drive unit at the bow can serve more than one sail, swap a furled gennaker off and a Code 0 on in the time it takes to pull a spring-loaded pin, without touching the drum. On a boat that carries both an asymmetric and a Code 0 and only flies one at a time, that saves buying a second drum unit entirely.

Facnor Fast FX+: the widest range, the simplest mechanism

Facnor's Fast FX+ leans on a straightforward anti-twist line system and quick-release pins rather than a proprietary bearing technology or ratchet, and that simplicity is part of the appeal. It is available across a genuinely wide SWL band, 900 kg to 7000 kg, which puts it on boats from 20 feet to 70 feet under the same product family. For a 40 to 50-foot cruiser looking for one reliable system without paying for a ratchet mechanism they may never need, the Facnor Fast FX+ Gennaker Furler is the system most 123Furling customers in that size range end up on.

Weight at the masthead matters more here than on a Code 0

A Code 0 furler carries the forestay's load and sits close to the deck's centreline. A gennaker furler's swivel lives up near the masthead, hoisted on its own halyard, so every gram in the swivel and the top of the drum adds pendulum weight exactly where you do not want it on a boat that already heels. Harken's Reflex uses a polycarbonate housing with a 6061-T6 aluminium disc rather than an all-metal build, and it is noticeably lighter aloft than the equivalent Profurl Spinex drum, which trades some of that weight saving for the larger Ø120-250mm bearing housing that gives it the higher MWL rating. If your boat already sails tender or you are chasing rig performance more than raw load capacity, the lighter option is worth the tradeoff even at a similar SWL rating.

The back-wrap problem none of the four brochures mention

Sailors on cruising forums flag the same failure mode across all four brands: back-wrap. It happens when the anti-torsion cable takes up a few turns of twist at the drum before the sail at the head actually starts rolling, and if you ease the sheet at that moment, the stored twist unwinds and winds the sail backwards on itself instead of forward. Untangling a back-wrapped gennaker at the dock, let alone at sea, can eat an entire afternoon. The fix that keeps coming up in forum threads has nothing to do with which brand you bought: keep the shock cord at the tack as tight as you can stand it, because that tension is what stops the twist building up at the bottom before it reaches the top. Loose shock cord is a bigger cause of jams than any difference between these four systems.

What these systems actually cost

Those are base configuration prices at 123Furling, not the price at your specific SWL, larger drums and longer AT-cables push the number up on all four. If you would rather skip the manual furling line entirely, the Seldén CXe electric gennaker furler is worth a look too, we covered when that upgrade pays for itself in our electric gennaker furler guide.

Not sure which sail area or SWL your boat actually needs? Use our product advisor or send the sail dimensions to info@123furling.com and we will size it with you before you order.