The highly anticipated Duotone Foil Assist 3-Blade SLS Propeller is finally here. Designed to unlock more power, speed, and performance from your Foil Assist setup, it's the most powerful propeller option in the range — and after weeks of back-to-back testing it ourselves in proper UK winter conditions, we can tell you exactly who it's for, and just as importantly, who it isn't.
| Blades | Build | Best For | Thrust |
| 3 | Aluminium | 80kg+ Riders | Highest in Range |
Built for Power and Earlier Take-Off
More thrust, quicker acceleration: the individually-tucking blade design — similar to traditional foil-drive systems — delivers significantly more low-end punch than either the standard or 2-blade SLS propeller. That means earlier take-offs, the ability to ride smaller foils and lower-volume boards, and noticeably higher top speeds on flat water. Despite the extra power, the more efficient delivery also means longer runtime per charge.
We Tested It Ourselves — Here's What We Found
We took all three propeller options out for a proper back-to-back test across two sessions on the south coast: a cold, low-tide morning at Shoreham with a nice ground swell running, and a smoother afternoon session at Goring on a higher tide. Riding the Duotone Mid Fish (38L) with a Crest 925 front wing at 70–72kg, the 3-blade was a different animal entirely.
Thrust-wise, it's in a different league — we were riding around gear 4–5 instead of the gear 6–7 needed on the 2-blade, with very fast vertical lift. But at our test weight, that lift came on faster than we could naturally counterbalance. The nose lifted quicker than expected, leading to some porpoising and, on a couple of occasions, getting launched clean off the board. Moving the mast back and switching to flatter water helped, but the underlying issue remained: this wasn't a technique problem, it was simply more power than our body weight was built to handle.
That's not a knock on the propeller. It's exactly why Duotone spec it for heavier and more advanced riders — for anyone at 80kg and above, or riding very small foils, that same thrust that overwhelmed us becomes a genuine advantage.
Compare the Full Range
| Propeller | Build | Best For |
| 2-Blade Regular | Fibreglass-reinforced plastic | Beginners, first-time users, light to mid-weight riders. Included as standard with every kit. |
| 2-Blade SLS | Aluminium | Advanced riders and foilers over 80kg wanting durability for open-ocean conditions, with strong low-speed torque and fast torque recovery exiting waves. |
| 3-Blade SLS | Aluminium | Advanced and/or heavier riders (80kg+) wanting maximum thrust, earlier take-off and higher top speed. |
Tech Specs
| Spec | Detail |
| Blade Count | 3, individually tucking |
| Material | Aluminium |
| Recommended Rider Weight | 80kg and above |
| Rider Level | Advanced — not recommended for beginners due to stronger, less progressive power delivery |
| Compatibility | Duotone Foil Assist system |
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