The FX 

When speed, exhilaration and athleticism is the ultimate, the FX provides it all.

The FX is a smaller sail and rig configuration based on the 49er platform. Designed for female and smaller teams, it uses a twin trapeze, self-tacking jib, asymmetric gennaker and solid wings. Hold on tight as the Mackay FX can reach speeds of 25 knots! It's the boat used by Olympic and World Champions.


Find out more in the Features section below



No of crew:                            2

Opt. crew weight:                 110 – 130kg’s

No. Trapeze:                          Twin

Hull material:                         GRP

Hull length:                            4.995m

Beam length:                        2.9m

Hull weight:                           94kg

Mainsail area:                       13.8sqm

Headsail area:                      5.1sqm

Spinnaker area:                    25.1sqm

Mast height:                          7.5M

The FX class rules stipulate that the hull, wings, foils, boom and pole must be 49er class parts.

FX Class Association website:


The Hull

The FX is 16ft long and made of fiberglass and carbon fibre for optimum strength and lightweight. Weighing 125 kgs when fully rigged, its optimal length to weight ratio and very fine hull lines, help produce excellent lift in waves and maneuverability.


 The Wings

The boat features distinctive wings 9ft wide to allow the crew to achieve maximum leverage and to support the rig. The wings are designed to blend into the hull and cockpit area which optimises aerodynamics and makes it easy to move around. The wings are fastened to the hull and can be easily detached. 


The Rig

The FX rig can go straight into an existing 49er boat. It is designed to produce the correct amount of power for a lighter weight crew so that they can fully power up at a similar windspeed as the men in the 49er and depower at a the same windspeed. It can compete with the 49er in many conditions.


CST became the carbon fibre tube suppliers in 2021. All tubes are QA checked plus bend and weigh tested by CST to ensure consistency.


The mast is assembled by the class builders. All mast fittings are the same on the 49er and FX so spare parts can be used for either boat.

The spreaders are built from recycled carbon. The mast join system and spreader base was recently redesigned for added strength around the trapeze area.


The FX jib sheet is allowed an extra purchase, and the gennaker sheet is allowed an extra block to increase the efficiency of the ratchet block.


The Sails

The huge sail area for such a small boat means that the FX can sail faster than the speed of the wind.


New sails

The Class is moving to a new range of sails in 2022. The main and jib sails will be built by North Sails using the 3Di technology  which is a 3D full sized molding construction process that uses composite materials. The technology enables sails to be built to the desired shape and retain shape over time. This change to the “black sails” will improve the longevity and consistency while also decreasing the overall cost of sails.

The spinnaker has also undergone design changes and will be built by North Sails.

The new sails are currently under development and due to be available in early 2022.


Class History & Developments

Mackay Boats Director, John Clinton, designed the FX rig/sail which made its debut at the 2016 Rio Games.

The FX was designed after the call went out by World Sailing (then ISAF) to develop a women’s skiff event for the Olympic Games.


The FX went through 9 months of testing by the Mackay team. It was then taken to Santander (ESP) for an ISAF evaluation trial where the FX was trialled against 5 other boats. The FX was finally selected at the ISAF mid-year conference in early May 2014.


Designing the FX was done through using the North Sails suite of analysis software and optimised using the Flow program.

The size of the main and jib were adjusted to get the correct fore/aft aerodynamic centre of effort to retain the same balance as the 49er. This also makes the boat easier to sail and easier to right from a capsize.

The main sail was introduced with a wider head based on developments in the 18ft skiff and America’s Cup technology. To make the head work, a stiffer mast was required. This was achieved by raising the hounds, similar to the top 18ft skiff teams, and adding a little carbon to the middle section of the mast to ensure the mid leech stays under control throughout the wind range.


The main was designed with only 5 battens to reduce the rig weight while using rugged purpose designed skiff cloth to ensure the sails last well.



Clinton has also designed the current carbon 49er rig and 18ft skiff rigs that have won recent World Championships.

Return to main FX Boats page 

Small gel coat repairs are relatively easy to do. 


What is Gelcoat made up of?

Gelcoat is a polyester product that is cured by using a catalyst called MEKP. (Methyl Ethyl Ketone Peroxide)

MEKP is a dangerous substance and should be treated as such when using, being very careful not to get any on your skin or in your eyes.


How can I get the catalyst - MERK?

We cannot ship MEKP so you will always need to buy it separately from your local marine store or fibreglass manufacturer.


How much MERK do I need?

The amount of Catalyst varies depending on the conditions you are using it in, but around 2%-3% will always work.


It is best to use a small syringe or dropper to get the required catalyst rate.

If you have mixed 100gm of gelcoat, then you are aiming for 2ml of catalyst.


Generally, polyester doesn’t stick well to Epoxy, so if you are repairing an epoxy boat, then you should source a special epoxy compatible gelcoat.


What are the Gelcoat colours?

Gelcoats colours are not always a 100% perfect match.

Colour will vary depending on the depth of the repair and the batch.

49er, VX One & Zephyr are built from Epoxy resin.


For the epoxy boats we use a product made by Scot Bader.

Grey is Crystic 253 RAL= 7035

White is Crystic 253 PA   - White 337


Does Mackay Boats supply gelcoat?

We supply a small tin (of each relevant colour) with each new boat.

Order additional gelcoat from our store, although it cannot be shipped by courier.


How do I do gelcoat repairs?

Doing gelcoat repairs is an art that improves with experience.

Making sure the surface is prepared well and keyed up is critical.

Overfill and then sanding back is a slow and time-consuming process.


Be very careful not to scratch the boat around the repair.

You shouldn’t sand the original surface around the repair with any paper coarser than 600grit.

Mask around the repair to protect the boat.

You can initially use a file or 150g to take the high parts off the filling, but don't use the coarse paper for too long or you will end up with scratches in the finished repair.


Once you have it fair with 600g, you can work your way through the sandpaper grades until you finish with 1500grit before cutting and polishing.


We would typically use 600g, then 800g or 1000g, then 1200g, then finally 1500g.

Sail numbers and flag details can be found on the class website: 49er / FX Class Association

Wings must be transported with the foam blocks under each wing to stop the underside denting on the wing plinths on the deck. Make sure they are tied down well so they don’t fly away!

Place padding under the ties in the non-skid areas to protect your non-skid and stop it wearing.

The class rules clearly state what can be added and changed on the boat as part of maintenance. Blocks and ropes can be replaced with similar products by other manufacturers. Please read the rules carefully and remember, you cannot change anything unless the rule specifically allow it.

The concept of the 49er is that all boats are the same. We offer the option to upgrade to EVA foam for non-skid on the wings and also offer a service to custom pack and align the centrecase.

The boat package comes complete with all ropes and sheets from Robline, rudderstock, 2 x tiller extensions, gennaker pole, boom and turnbuckle set.

The Rig package comes complete with mast, wires, halyards, halyard adjusters, trapeze lines and trapeze adjusters.

***Boatbreaker and footstraps are not included and need to be ordered as extra items.