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2026: Duotone
SKU:
40260-4001

Foil Assist Mast Set

£3,999.00
£0.00 £3,999.00
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Prone / Downwind / Wake / Wing Foil

The Foil Assist Alloy Mast is designed to enhance your foiling experience by combining power, manoeuvrability, glide, and modularity. With a single size of 84 cm, this mast is ideal for prone and downwind foiling. It's also excellent for wake foiling in tanker waves and wing foiling in light winds.

FULL DESCRIPTION

The Foil Assist Alloy Mast is designed to enhance your foiling experience by combining power, manoeuvrability, glide, and modularity. With a single size of 84 cm, this mast is ideal for prone and downwind foiling. It's also excellent for wake foiling in tanker waves and wing foiling in light winds.

At the core of this mast is a motor pod that is seamlessly integrated into the mast profile, positioned 17 cm below the top plate. This integration not only enhances aesthetics but also contributes to performance. The mast features internally routed cables, ensuring optimal glide and maximum maneuverability. Its rigid, surf-inspired profile provides precise control and instant responsiveness while minimising drag for smoother, more efficient sessions.

Powered by a high-torque motor with a maximum thrust of 33 kg, the Foil Assist Mast AL enables the use of smaller foils and boards, resulting in greater responsiveness, manoeuvrability, and control. Safety and efficiency are further enhanced by a powerful folding gear propeller that opens and rotates only when the motor is engaged and automatically closes when the ring controller button is released, minimizing drag and enhancing safety during use. For additional torque, you can replace the plastic propeller blades with aluminum power propeller blades.

The placement of the receiver in the battery box on the harness ensures optimal signal transmission to and from the remote, providing reliable power throughout your session. This effectively addresses a common pain point associated with foil assist products, making this mast a perfect option for seasoned foilers looking to push their limits.

 Designed for complete modularity, the Foil Assist Mast AL allows for effortless swapping of the motor and connector cable throughout the entire Assist mast range. Its fuselage adapter system is compatible with most major foil brands, including Duotone, F-One, Armstrong, Gong, Axis, Lift, North, Code, Sab, AFS, and KT, granting you the freedom to use your preferred foils while benefiting from the advanced Duotone Foil Assist technology. Furthermore, the mast can be attached to any mid-length prone or wing board featuring standard US foil tracks, enhancing its versatility.

To maximise battery runtime with your Foil Assist, we recommend using a front wing with a surface area of 900 cm2 or larger, along with a board that has a minimum volume of 35 L. 

Whether you're looking to enhance your sessions or push your performance, every detail of the Foil Assist Mast AL has been engineered for a seamless and intuitive assist experience in all conditions.

HARNESS

Unlike conventional systems that mount the batteries on the mast top plate or the board, the Duotone Foil Assist batteries (2 x 1 kg) are placed in a waterproof box attached to a comfortable waist harness. This arrangement ensures that the board-foil setup remains perfectly balanced despite the motor, preserving the pure feel of foiling as much as possible. A backpack with batteries has the disadvantage of placing weight on the shoulders, which can disrupt balance during turns and quick movements.

With the harness, the weight sits on the hips, where it does not affect your balance, and you have full freedom of movement in your upper body. You will hardly notice the weight of the harness (approximately 3.76 kg, including the box and batteries) after just a few minutes. The connection between the batteries and the motor is made via a cable that runs along a shorter leash from the battery box to the top plate of the mast. The board leash is attached below the cable port of the battery box to the harness. The receiver for the remote control is mounted in the lid of the battery box, ensuring a more reliable connection between the remote and the motor, as the Bluetooth signal is not disrupted by water.

The eHarness has been designed with a clear focus on safety and user-friendliness. The magnetic buckle and the Velcro neoprene strap allow for quick and easy removal. With the adjustable buckle, you can customize the harness to fit your individual waist size. If you need to detach the harness underwater, you can easily do so with a quick tug. Additionally, the harness is made from non-water-absorbing materials and features built-in buoyancy, allowing it to float independently and not pull you down in the water. To prevent the battery box from opening under water pressure, it is protected with a neoprene cover that can be opened using a large zipper.

When developing the Foil Assist, our primary goals were to create a system that is light, small, and simple to maintain, while preserving the pure feel of foiling as much as possible. We achieved this by strategically placing the batteries (2 × 1 kg) in a waterproof case on a waist harness, rather than on the board or the top plate of the mast.

To connect the batteries to the motor integrated into the mast, a cable runs alongside a shorter leash from the battery box to the top plate of the mast. The shorter board leash connects just below the cable port of the battery box to the harness.

Riders will quickly get used to the weight of the harness (approximately 3.76 kg, including the box and batteries), while appreciating the feeling of an evenly balanced board with no excess weight beneath their feet. This innovative battery placement improves the motor’s responsiveness and ensures quicker acceleration compared to traditional battery placements underneath the board.

The harness has been designed with safety and simplicity in mind. Its magnetic attachment system allows for quick and easy detachment, making it user-friendly for all riders. For a tailored fit, the adjustable sizing buckle accommodates various body sizes from S-M to L-XXL. To provide added peace of mind while riding, the harness is equipped with a quick-release safety mechanism. Additionally, it is constructed from non-water-absorbing materials and features built-in buoyancy, allowing the harness to float independently and providing an extra layer of safety in the event of a fall. To prevent the battery box from opening during wipeouts, we included a neoprene cover with an easy-to-open zipper on top.


Recommended Board & Foil Setup

Midfish

Skybrid / Skybrid SLS Crush SLS (40 L)

Duotone Adapter Fuselage Fuselage Aero Tail D/LAB Fuselage Aero AL 3BS

Crest D/LAB

Glide 2.0 D/LAB

Glide 2.0 SLS

Free SLS

Back Wing Stabilizer S Back Wing Stabilizer H Back Wing Stabilizer C

KEY FEATURES

LOW DRAG THROUGH SEAMLESS INTEGRATION

The fully integrated motor pod, fixed at 17 cm below the top plate, and internally routed cables optimize glide and manoeuvrability, while allowing for easy assembly.

STIFF ALLOY MAST FOR A DIRECT RESPONSE The stiff alloy mast features a rigid, surf-inspired profile that ensures precise control and instant responsiveness, minimizing drag for smoother and more efficient sessions.

HIGHLY MODULAR

The Foil Assist Mast AL is designed for modularity, enabling effortless swapping of the motor and connector cable across the entire Foil Assist mast range. Its quick swap adapter system is compatible with fuselages from all major foil brands, including Duotone, F-One, Armstrong, Gong, Axis, Lift, North, Code, Sab, AFS and KT, as well as with any prone or wing board using standard US foil tracks.

UNPARALLELED THRUST 

TO GET ON FOIL EVEN SOONER

Powered by a high-torque motor with a maximum thrust of 33 kg, the Foil Assist Mast AL enables the use of smaller foils and boards, resulting in greater responsiveness, manoeuvrability, and control.

POWERFUL FOLDING PROPELLER 

FOR MINIMIZED DRAG AND SAFETY

The powerful folding gear propeller, which only opens when the motor is engaged, ensures minimized drag and enhanced safety during use. For additional torque, you can replace the plastic propeller blades with the power propeller blades made out of aluminium.

CONSISTENT PROPULSION AND OPTIMAL SIGNAL

The placement of the receiver in the battery box on the harness ensures optimal signal transmission to and from the remote, providing reliable power throughout your session.

WARNING: Due to safety reasons concerning the propeller, please do not use the assist masts with a pump board or a prone board that has a foil box position close to the tail.

SIZES

S – M (WAIST MEASUREMENTS: 71 – 89 CM / 28" – 35")

L – XXL (WAIST MEASUREMENTS: 89 – 114 CM / 35" – 45")

SET INCLUDES

FOIL ASSIST MAST AL WITH MOTOR, PLASTIC PROPELLER, MAST COVER, AND MOTOR BELL & PROPELLER COVER

SCREWS AND TOOLS

CONNECTOR CABLE AND LEASH

CABLE FASTENER V, CABLE FASTENER (4PCS)

EXTRA PROPELLER BLADES REGULAR (2PCS)

HARNESS SET

REMOTE WATCH RING SET

BATTERY CHARGER SET

2 × BATTERIES AND BATTERY BAG
PRODUCT INFORMATION

Prone / Downwind / Wake / Wing Foil

The Foil Assist Alloy Mast is designed to enhance your foiling experience by combining power, manoeuvrability, glide, and modularity. With a single size of 84 cm, this mast is ideal for prone and downwind foiling. It's also excellent for wake foiling in tanker waves and wing foiling in light winds.

FULL DESCRIPTION

The Foil Assist Alloy Mast is designed to enhance your foiling experience by combining power, manoeuvrability, glide, and modularity. With a single size of 84 cm, this mast is ideal for prone and downwind foiling. It's also excellent for wake foiling in tanker waves and wing foiling in light winds.

At the core of this mast is a motor pod that is seamlessly integrated into the mast profile, positioned 17 cm below the top plate. This integration not only enhances aesthetics but also contributes to performance. The mast features internally routed cables, ensuring optimal glide and maximum maneuverability. Its rigid, surf-inspired profile provides precise control and instant responsiveness while minimising drag for smoother, more efficient sessions.
Powered by a high-torque motor with a maximum thrust of 33 kg, the Foil Assist Mast AL enables the use of smaller foils and boards, resulting in greater responsiveness, manoeuvrability, and control. Safety and efficiency are further enhanced by a powerful folding gear propeller that opens and rotates only when the motor is engaged and automatically closes when the ring controller button is released, minimizing drag and enhancing safety during use. For additional torque, you can replace the plastic propeller blades with aluminum power propeller blades.
The placement of the receiver in the battery box on the harness ensures optimal signal transmission to and from the remote, providing reliable power throughout your session. This effectively addresses a common pain point associated with foil assist products, making this mast a perfect option for seasoned foilers looking to push their limits.
 Designed for complete modularity, the Foil Assist Mast AL allows for effortless swapping of the motor and connector cable throughout the entire Assist mast range. Its fuselage adapter system is compatible with most major foil brands, including Duotone, F-One, Armstrong, Gong, Axis, Lift, North, Code, Sab, AFS, and KT, granting you the freedom to use your preferred foils while benefiting from the advanced Duotone Foil Assist technology. Furthermore, the mast can be attached to any mid-length prone or wing board featuring standard US foil tracks, enhancing its versatility.
To maximise battery runtime with your Foil Assist, we recommend using a front wing with a surface area of 900 cm2 or larger, along with a board that has a minimum volume of 35 L. 
Whether you're looking to enhance your sessions or push your performance, every detail of the Foil Assist Mast AL has been engineered for a seamless and intuitive assist experience in all conditions.

HARNESS

Unlike conventional systems that mount the batteries on the mast top plate or the board, the Duotone Foil Assist batteries (2 x 1 kg) are placed in a waterproof box attached to a comfortable waist harness. This arrangement ensures that the board-foil setup remains perfectly balanced despite the motor, preserving the pure feel of foiling as much as possible. A backpack with batteries has the disadvantage of placing weight on the shoulders, which can disrupt balance during turns and quick movements.

With the harness, the weight sits on the hips, where it does not affect your balance, and you have full freedom of movement in your upper body. You will hardly notice the weight of the harness (approximately 3.76 kg, including the box and batteries) after just a few minutes. The connection between the batteries and the motor is made via a cable that runs along a shorter leash from the battery box to the top plate of the mast. The board leash is attached below the cable port of the battery box to the harness. The receiver for the remote control is mounted in the lid of the battery box, ensuring a more reliable connection between the remote and the motor, as the Bluetooth signal is not disrupted by water.

The eHarness has been designed with a clear focus on safety and user-friendliness. The magnetic buckle and the Velcro neoprene strap allow for quick and easy removal. With the adjustable buckle, you can customize the harness to fit your individual waist size. If you need to detach the harness underwater, you can easily do so with a quick tug. Additionally, the harness is made from non-water-absorbing materials and features built-in buoyancy, allowing it to float independently and not pull you down in the water. To prevent the battery box from opening under water pressure, it is protected with a neoprene cover that can be opened using a large zipper.

When developing the Foil Assist, our primary goals were to create a system that is light, small, and simple to maintain, while preserving the pure feel of foiling as much as possible. We achieved this by strategically placing the batteries (2 × 1 kg) in a waterproof case on a waist harness, rather than on the board or the top plate of the mast.

To connect the batteries to the motor integrated into the mast, a cable runs alongside a shorter leash from the battery box to the top plate of the mast. The shorter board leash connects just below the cable port of the battery box to the harness.

Riders will quickly get used to the weight of the harness (approximately 3.76 kg, including the box and batteries), while appreciating the feeling of an evenly balanced board with no excess weight beneath their feet. This innovative battery placement improves the motor’s responsiveness and ensures quicker acceleration compared to traditional battery placements underneath the board.

The harness has been designed with safety and simplicity in mind. Its magnetic attachment system allows for quick and easy detachment, making it user-friendly for all riders. For a tailored fit, the adjustable sizing buckle accommodates various body sizes from S-M to L-XXL. To provide added peace of mind while riding, the harness is equipped with a quick-release safety mechanism. Additionally, it is constructed from non-water-absorbing materials and features built-in buoyancy, allowing the harness to float independently and providing an extra layer of safety in the event of a fall. To prevent the battery box from opening during wipeouts, we included a neoprene cover with an easy-to-open zipper on top.

Recommended Board & Foil Setup

Midfish

Skybrid / Skybrid SLS Crush SLS (40 L)

Duotone Adapter Fuselage Fuselage Aero Tail D/LAB Fuselage Aero AL 3BS

Crest D/LAB

Glide 2.0 D/LAB

Glide 2.0 SLS

Free SLS

Back Wing Stabilizer S Back Wing Stabilizer H Back Wing Stabilizer C
KEY FEATURES

LOW DRAG THROUGH SEAMLESS INTEGRATION

The fully integrated motor pod, fixed at 17 cm below the top plate, and internally routed cables optimize glide and manoeuvrability, while allowing for easy assembly.

STIFF ALLOY MAST FOR A DIRECT RESPONSE The stiff alloy mast features a rigid, surf-inspired profile that ensures precise control and instant responsiveness, minimizing drag for smoother and more efficient sessions.

HIGHLY MODULAR

The Foil Assist Mast AL is designed for modularity, enabling effortless swapping of the motor and connector cable across the entire Foil Assist mast range. Its quick swap adapter system is compatible with fuselages from all major foil brands, including Duotone, F-One, Armstrong, Gong, Axis, Lift, North, Code, Sab, AFS and KT, as well as with any prone or wing board using standard US foil tracks.

UNPARALLELED THRUST 

TO GET ON FOIL EVEN SOONER

Powered by a high-torque motor with a maximum thrust of 33 kg, the Foil Assist Mast AL enables the use of smaller foils and boards, resulting in greater responsiveness, manoeuvrability, and control.

POWERFUL FOLDING PROPELLER 

FOR MINIMIZED DRAG AND SAFETY

The powerful folding gear propeller, which only opens when the motor is engaged, ensures minimized drag and enhanced safety during use. For additional torque, you can replace the plastic propeller blades with the power propeller blades made out of aluminium.

CONSISTENT PROPULSION AND OPTIMAL SIGNAL

The placement of the receiver in the battery box on the harness ensures optimal signal transmission to and from the remote, providing reliable power throughout your session.

WARNING: Due to safety reasons concerning the propeller, please do not use the assist masts with a pump board or a prone board that has a foil box position close to the tail.

SIZES

S – M (WAIST MEASUREMENTS: 71 – 89 CM / 28" – 35")

L – XXL (WAIST MEASUREMENTS: 89 – 114 CM / 35" – 45")

SET INCLUDES

FOIL ASSIST MAST AL WITH MOTOR, PLASTIC PROPELLER, MAST COVER, AND MOTOR BELL & PROPELLER COVER

SCREWS AND TOOLS

CONNECTOR CABLE AND LEASH

CABLE FASTENER V, CABLE FASTENER (4PCS)

EXTRA PROPELLER BLADES REGULAR (2PCS)

HARNESS SET

REMOTE WATCH RING SET

BATTERY CHARGER SET

2 × BATTERIES AND BATTERY BAG

DELIVERY & RETURNS

Life is complicated enough, so we've made returning items as simple as possible for mainland UK. Head to your account and click the link for returning items and we'll take it from there. For exchanges, simply select "refund" and re-order the required item again. We'll refund the very moment it's returned to us.

For NI, Channel Islands, Europe and Rest of World, you the customer will need to return the item to us as collections are not possible.

For item's where we've made a mistake or the item is faulty - we'll refund all postage costs on receipt of postage receipt and dispatch replacements items FOC. For items simply no longer required or where you the customer has ordered the incorrect size or product, return postage will not be refunded and dispatching out will be chargeable.
£3,999.00
£0.00 £3,999.00

Let customers speak for us

from 131 reviews

Nice to not have to rinse the charging pins on the woo after every session ;)

Renato
Woo 4.0

great communication and delivered the product when they said. Would definitely use again!

Chris Hover
H20 Sports
Wing Foiling Gear

I cannot sing enough praises for H2O Sports! I have over the years made small purchases because they’ve been the most competitive online but recently I bought some new wing foiling kit and there was some slight damage to the alloy mast - well H2O’s aftercare was second to none!! They were instantly chasing down a replacement part and happy for me to be using the old part (albeit a bit bent) whilst waiting for the replacement. So refreshing to experience such great customer service.
Many many Thanks! - will be ordering more and more from this company!!!

Mike
H20 Sports

Great buying experience. Great prices and delivered quickly. Thanks Guys.

Andy PG
H20 Sports
Duotone Unit SLS 2025

After purchasing this wing earlier this year it has noticeably made tacks so much smoother and overall upgraded my riding. I bought the 3.0 and 5.0 metre and my 3.0m flies very well in both underpowered and overpowered conditions

Emma
Unit SLS Concept Blue Wing
Duotone Carve DLAB and Unit SLS wing

I purchased the Unit SLS 2025 wing earlier this year and it has made tacks so much smoother and upgraded my riding. I also bought the Duotone Carve 3.0 D/LAB 2025 with the 800 front wing and once again it’s been a game changer, having a great amount of glide which works perfectly for both wingfoiling and kitefoiling!
All thanks to the H2O team that always have loads of knowledge, passion for watersports and go above and beyond!

Emma
H20 Sports

Preferring not to throw away my (now discontinued) North Red boom which had a broken cuff, I called H2O to see if there was any way to salvage it. I spoke with Matt who was very knowledgeable and helpful but came off the phone somewhat resigned that I might not be able to get the part. However to my surprise a little while later I was blown away (with a force 5) when I got a call to tell me he’d sourced one for me. And here I am now, a week on, with all the bits I need to get back on the water; whoever said people don’t have time to help others! So the moral of this story is have a little faith and try H2O!

Davalar Kinsey
H20 Sports
5* Service - Putting customers first 5*

Preferring not to throw away my (now discontinued) North Red boom which had a broken cuff, I called H2O to see if there was any way to salvage it. I spoke with Matt who was very knowledgeable and helpful but came off the phone somewhat resigned that I might not be able to get the part. However to my surprise a little while later I was blown away (with a force 5) when I got a call to tell me he’d sourced one for me. And here I am now, a week on, with all the bits I need to get back on the water; whoever said people don’t have time to help others! So the moral of this story is have a little faith and try H2O!

Davalar
H20 Sports
Light wind lift

Ordered a 1350 Glide 2.0 to progress on to from my 1750 aero free. Being a heavier rider I've found it's now my go to foil wing, initially a bit harder to get on the foil compared to the aero free but once up it feels completely effort less! Thanks to the team for getting me sorted out 🤙

Kyle Gould
Glide 2.0 SLS Wing Set
The best in the business.......

James, Matt and the H20 Team are absolute gurus of the water sports industry, friendly, helpful and knowledgable. They will always give the right advice and come up with superb deals and first class support, thanks guys for always helping me to make the right decisions over the last 20 + years!

Tim H
H20 Sports
Duotone slim 2.0 Dlab 2.0 carbon mast

My new mast arrived from H20. Sports and it was so worth the wait. You immediately notice how much stiffer it is compared to the v1 carbon version when riding. The foil feels more responsive and direct .It also glides longer in transition s and riding bumps.
Its well worth the upgrade in my opinion.

Tim
Foil Mast Slim 2.0 D/LAB
Duotone Float 5 m is a summer light wind weapon

I bpught this wing to replacr my Unit 5.5 m wing for tje summer breezes as i never liked using big wings. This wing is really powerful in the low end and allows you to pump really efficiently to get on foil with a bit of technique.
You can size down by half a metre with this wing compared to a Unit.
Its still fast and so good iwhen you roll into a tack.
Perfect quiver would be a 3 m , 4m & a 5 m in the Float for all conditions.
Its a great price too as lower than Dlab and SLS wings but with great performance.

Tim
Float Wing
Duotone sky surf/sky style, Duotone unit, Dlab foil range.

As one of the H2O riders I have really enjoyed the variety of kit H2O have available. Including the Duotone sky surf 35Ltr which quickly become my favourite board because of its shorter and thicker shape while being low in litres it still allows me to get it out the water in some lighter winds. However it comes into its own when the wind is strong and the waves are pumping with its incredible manoeuvrability. Paired with the Duotone units (that are light weight and precisely balanced) wave riding is a dream.

Ted Lockyer
H20 Sports
New to downwind boards and loving it!

I've been one of those riders who thought one board was enough. Turns out a downwind board has opened up so many more days on the water. I cant believe how easy this beast gets going in 6 knots. I use my 8' board with the 1100 and 1595 Duotone Glide. It's like a whole new sport. Whilst I've tried paddling up, I think I'll stick to winging for now (although can't wait to try the Stash Parawing).

Graham Lockyer
Downwinder SLS Wing Board
Enhanced low-end power, stability, and maneuverability at a great price

Lots of the benefits of the DLAB Unit but without the price tag. Strong, light, and powerful. It's been great in all conditions, handles really well when over powered. I bought the 3.5, 4.5 and 5.5 to cover all eventualities. Personally I prefer the handle option which works really well with my harness. Matt and the team really helpful in deciding on the sizing.

Graham Lockyer
Unit SLS Concept Blue Wing