New rudder horizontal foils from Mackay Boats make their SailGP debut in Geneva
by Julia Faire/Mackay Boats 29 Sep 21:25 PDT
The finished light air F50 rudder foils - Mackay Boats - September 2025 © Mackay Boats
SailGP's latest innovation isn't just about performance on the water—it's in how the boats fly. At the Geneva stop, teams raced for the first time with newly designed light-air rudder wing foils on their F50s, built specifically to excel in low-speed conditions.
What makes these foils different?
The foils are designed with a new section that is larger in area than the standard foils. This provides extra lift, helping teams stay foiling even through slow manoeuvres and patchy breeze, where maintaining flight can make or break a race.
The new light-air rudder elevators were built by Mackay Boats, employing techniques they've honed in the high-performance Moth world.
Collaborating with SailGP designer Paul Bieker, Mackay's used a different manufacturing process from how the other F50 foils have been constructed, with the carbon foil tips being moulded in a single cure inside a closed mould — the same method Mackay's employs for building their Moth foils. This approach ensures maximum repeatability and precision, meaning all teams use the same equipment.
Structurally, the foils are composed of a blend of carbon and titanium with foam cores. The titanium fuselage and bulb provide the strength and hydrodynamics necessary at the join to connect accurately to the rudder vertical. Most of the foil is carbon, which fits perfectly onto the titanium centrepiece.
The foil's trailing edge is reinforced with a 0.4 mm titanium insert, integrated into the carbon to maintain sharpness and durability.
The foils are painted by Mackay's specialised painting and finishing team. A significant challenge lies in the design and execution of bonding the carbon to the titanium, which is exactly the same process Mackay's uses in building their Moth Verticals.
For SailGP, the move to Mackay's build process wasn't accidental. The league had already seen the success of Mackay's Moth steel foils and wanted the same repeatability and precision in the F50's new light-air package.
The sailors have been quick to notice the difference. Swiss driver Seb Schneiter summed it up: "The new light air rudder elevators are a big upgrade for the fleet, giving us much more glide at lower speed, opening up the possibility for more manoeuvres and better racing. This is key when coming to light air venues like Geneva to guarantee a good show for the fans."
From the builder's side, SailGP Technologies' Operations Manager Ben Hanley called the project a success:
"Mackay Boats provided us with a top to bottom solution for production of our gen2 LARW foils. We are pleased with the outcome. The Mackay's team has been confidence-inspiring throughout the project, providing excellent build quality and delivered on time."
In the end, Geneva showed that these foils aren't just another technical upgrade - they're a practical tool that helps the F50 fleet put on a proper show even when the wind doesn't play ball. And for the sailors, that means more options, more manoeuvres, and more chances to keep the race alive when the breeze goes soft.
Additional Images: