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The Flying Fifteen Jib Revisited

A review of the new jib and its control arrangements

The Flying 15 jib revisited

The new jib entered service in early 2017, following the 2016 FFI ballot. It followed over a decade of staggered development, with different sail designs considered and trialled. The expert view was that the longer luff and shorter foot arrangement offered a modern, crew-friendly, better looking and longer lasting option for the Flying Fifteen class.

Now, with four years’ experience, we asked some of the sail makers and some class experts on whether these goals have been delivered, and what the change has meant for the Flying Fifteen class.

A New Design

The sail area of the jib and genoa are identical – 3.832m2 (41.25 sqft). However, the dimensions are quite different with the jib 300mm longer in the luff, 204mm longer in the leech and 182mm shorter in the foot. This configuration results in a centre of effort slightly farther forward and higher than the genoa. This should mean slightly less weather helm, which may benefit some classic Flying Fifteen designs. Richard Whitworth (North Sails) ran the numbers in North’s sail design software (see accompanying article), finding that the performance difference between the two shapes to be insignificant – within 0.2% of each other!

The Genoa and the Jib Side-by-Side
The Genoa and the Jib Side-by-Side

Performance isn’t just about straight-line speed. One benefit of the jib over the genoa is that the shorter foot means less sheeting on each tack. In this sense, the jib is a crew-friendly option and, in theory, has lower sheet loads. Richard Lovering (Hyde Sails) stressed that the benefits of lower sheet loads were marginal and many crews would benefit from ratcheted jib blocks: “this allows the crew to ease just a few millimetres – which eases the leech 1-2cm. Even with a strong crew, this level of control is impossible without a ratchet and it is the first thing we upgraded on our boat.”

If you’re sailing a 75 year old design, aesthetics are important and the new jib received a ‘thumbs up’ on this score as well, with its longer leech and rounded foot getting the thumbs up. Several helms also noted the improved visibility behind the jib that represented an important safety improvement as the dreaded genoa ‘blind spot’ is significantly reduced.

A common misconception is that the upgrade to a new jib also requires a new main. Obviously, having two brand new sails is nice, but this needn’t delay the switch. Ian Pinnell (Pinnell & Bax) noted that their main design hadn’t changed with the introduction of the new jib and, as long as the main is in good condition, it would performance equally well with the jib and genoa. Richard Lovering (Hyde Sails) explained that while they had continued to refine the Hyde sail designs, the benefits of having a new jib outweigh an old genoa with an equal vintage main sail.

What really matters is the controlling the slot between the main and jib. Steve Goacher (Goacher Sails) explained: “Since the new jib has less main overlap, managing the slot vertically is really important to get the best out of the boat. That will be a little bit different between every boat, but it doesn’t mean a new main is a necessity.”

Replacing the jib halyard

As the new jib’s luff length is 300mm longer than the genoa, the jib halyard needs replacing. This is a straight forward five minute job. The only difficult can be getting the ferrul (swage) through the halyard sheave on the mast. Sometimes this can involve a bit of jiggery-pokery – or in the worst case dropping the mast. If you aren’t ready to part with your genoas, you could switch halyards as needed but the easier way is to purchase a 300mm long wire strop that lengthens the halyard for days when the family cruise warrants the vintage genoa.

Ian Pinnell suggested that replacing the jib halyard is also a good time to check the furler bearings and ensure that the upper swivel isn’t upside-down. When the class first transitioned to the new jib, there were some halyard breakages on boats running 3mm halyard wire. As it transpired, the problem wasn’t the wire but that the upper swivel wasn’t rotating under load. With the furling load now falling on a shorter halyard section between the jib head and mast sheave, the breakages occurred because the halyard wire was being unravelled as the jib was being furled! Most boats are now running a thicker 3.5mm halyard, but furler maintenance is still advised. Charles Apthorp added that it is always a good idea to “unroll the jib against the turn of the wire, which stops it unravelling when it is max loaded.”

Some chute boats have experienced spinnaker halyard fouling when the jib is being furled. This occurs because the jib head is closer to mast and more likely to catch on the spinnaker halyard. Murphy’s Law states this is most likely when the jib is being unfurled in the prestart with 15 seconds to the gun. Some boats have added a CD sized disc at the head of the jib to prevent fouling, but another top tip is for the crew to reach out onto foredeck during the prestart and pull the spinnaker halyard down an extra couple of feet in the prestart. A slack spinnaker halyard substantially lessens the risk of fouling.

Jib Clew

The shorter foot and longer leech means that the clew that sits forward and lower compared to the old genoa. This means the jib fairlead will need to be adjusted forward. As a starting point, Ian Pinnell (P&B) suggests a fairlead position 3150mm from the transom. This is also 350mm forward of the P&B recommended genoa position.

This measurement depends on the forestay position, but is a good guide to the maximum forward position of the jib fairlead. In many cases, this can be managed on the existing jib track, but in some cases the track will need to be either extended forward or moved.

The shorter foot also means that that the jib should be trimmed closer to the centre to maintain the same sheeting angle as the genoa. The simplest way to think of this is to draw a line from the tack back to the genoa car. The new jib car position will be on this line – forward of the genoa car and slightly inboard as well.

At the pointy end of the fleet there has been a lot of experimentation with the clew position – not only moving the fairlead forward, but also experimenting with even tighter sheeting angles. Some top sailors have discovered that in the right conditions the boat can be sailed on even tighter sheeting angles – pointing higher, though not necessarily faster.

The advantages of pointing higher and slower are mostly at the start when holding a lane is crucial, but there are other occasions when it can be useful. However, Steve Goacher (Goacher Sails) cautions that sailing in high mode is like “sailing on the edge of a knife as you run a high risk of closing the jib/main slot. Any sudden drop in wind pressure could bring the jib inward and, in a gust, easing the main to manage a gust also risks closing a narrow slot. It’s fast, but unforgiving.”

Richard Lovering (Hyde Sails) agrees, noting that it only really works “in a narrow wind range when the boat is full powered. In lighter and heavier winds having a wider slot is more and tight sheeting angles won’t work. We use the same sheeting angle on the new jib as we had on the genoa, but to achieve this we moved the tracks forward and inboard.”

Although many of the top boats follow Richard’s example, relocating the tracks as close to the vertical section of the side tank as possible, it is interesting to look at the other systems being tried and tested. I’ve tried summarising four options below:

4071 - “470 Gearbox”

4071 “470 Gearbox”
Click to enlarge
The International 470 approach uses a ‘gearbox’ to adjust the jib block inboard, while the jib car fore/aft position is adjusted while hiking. The jib track has been moved forward as close the vertical section of the side deck as possible.

This system was used by Graham Vials and Charles Apthorp at the 2019 Worlds, but requires the jib track to be moved onto the vertical side tanks of the OviX. The Gearbox is available from Mackay Boats in New Zealand, although Allen Brothers produce a similar version in the U.K.

4078 - “The Goachauler”

4078 “The Goachauler”
Click to enlarge
First used by Steve Goacher at the 2019 Worlds in Ireland, the inboard puller pulls a floating block in front of the jib fairlead. The puller runs to the windward side of the boat to a fairlead just in front of the jib track and then, via a 2:1 purchase, to a side cleat. This enables the sheeting angle to be adjusted on the windward side of the boat while hiking.

The system is cheap, simple, and doesn’t require the tracks to the moved inboard. While it does mean more string crossing the boat, it should (in theory) be out of the way of the crew.

4073 - “Twin Tracks”

4073 “Twin Tracks”
Click to enlarge
Chris Ducker’s new boat uses custom ‘pods’ added to the side wall to run the main jib track, setting a maximum inboard position. The jib sheet then runs through an out-hauling block which is adjusted on the secondary track. The jib cars on both tracks are linked.

This system was put together by Phil Evans (Phil Evans Sailing Services) and a video of the system can be found on YouTube.

3760 - “The Positionator”

3760 “The Positionator”
Click to enlarge
Jeremy Davy’s “Positionator” takes inspiration from the Fireballs and moves away from jib cars to a system that adjust the jib block up and down, and inboard and out. This can be adjusted by the crew while hiking. MkV is pictured, MkVI has now been fitted!


Putting it all together, most sailmakers sell the new jib for either side £450 depending on whether they are running a sale. The shorter halyard will set you back a further £40, and a further £15 for the halyard lengthening strop if you wish to cruise with your genoas from time to time. Some crews have added a disc to the halyard, adding a further £5.

So, the minimum spend is about £500. You can add £100-200 if you need to lengthen or move the tracks, or add a system to manage the clew position – and a bit more if that work is undertaken professionally. All-in-all, about £500-700 – or £50-£250 above the end-of-life sail replacement cost.


Interestingly, in collating this article, the feedback and experiences on the new jib were universally positive across the board. For some, planning clew systems and testing how they perform on the water has improved their enjoyment of the class.

The old style genoa is still commonly used in club racing fleets, but as these sails age many classic Flying Fifteens are looking at the new jib and what it means for their boats. There has been some reluctance, with stories of snapped halyards, moving jib tracks and spinnaker halyard fouling making the rounds. However, with four years of fleet-wide experience, these problems have been solved.

In short, the new jib has been a welcome addition to the class and a worthwhile investment.


UK FFA wishes to thank Steve Goacher, Ian Pinnell, Richard Lovering, Richard Whitworth, Charles Apthorp, Nathan Batchelor, Jeremy Davy, John Hanson, Alastair Stevenson and Mervyn Wright for their insights.
Picture credits to Nathan Batchelor, Richard Jones, Jeremy Davy and UK FFA.

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