Foil Assist Guide

Everything you need to know before buying a Duotone Foil Assist or Foil Cruise: how it works, which set fits you, and how to look after it. Questions? Email yaz@calikites.com.

Jump to: How it works · Which set? · What's in the box · Batteries & runtime · Remote · Harness sizing · Care & safety · FAQ

How it works

The motor is built into the mast. You get on your board, press the remote, and the motor gives you enough push to get up on foil. Once you're flying, you turn it off and ride the foil like normal. The two-blade propeller folds away when the motor is off, so it doesn't drag while you glide.

The batteries ride on your hips in a waterproof box on the eHarness, not on the board. That keeps the board light and lets it feel like normal foiling. A cable runs along a short board leash from the harness to the mast.

Use it for prone foiling, downwinders, light-wind winging and wake. Duotone rates the motor at up to 33 kg of thrust.

Which set is right for you?

Set	Best for	Price
Foil Assist Set AL	Most riders. 84 cm aluminum mast that works with Duotone and 10 other foil brands using an adapter.	$5,699
Foil Assist Set D/LAB	Experienced riders on Duotone (or Armstrong) foils who want the lightest, slimmest, best-performing mast.	$6,999
Foil Cruise Set AL	Newer foilers and flat-water cruising. Shorter 80 cm mast, motor low on the mast, optional prop guard.	$5,699
Foil Assist Complete AL / Foil Cruise Complete AL	Starting from scratch. The same systems with the board included, sized by harness, front wing and board length.	From $7,514

Not sure your current foil will work? Check the compatibility chart. The AL and Cruise sets need a fuselage adapter for your foil, sold separately.

What's in the box

The Assist and Cruise sets include the eMast with motor, propeller and covers, the eHarness with battery box, the watch and ring remote, two batteries, the charger set, a battery bag, the connector cable and leash, cable fasteners, spare propeller blades, and a screw set with tools. The fuselage adapter, front wing and stabilizer are not included in the non-complete sets.

Batteries & runtime

• Two LiHV batteries, each 7 Ah, 22.8 V, 159.6 Wh and about 1 kg. Both must be connected to run the motor.
• Runtime is typically 30 to 60 minutes, depending on your skill, weight, conditions, board size, speed setting and how efficient your foil is. A second battery set keeps you on the water longer.
• Four lights on each battery show charge. Two or three lights is the right level for storage.
• Each battery is just under the common 160 Wh airline limit. Airlines vary, so get approval before you travel.
• Always store batteries in a fire-resistant bag when you're not using them. The set includes one.
• Extras: smart dock, extra charger, all batteries & chargers.

The remote

The waterproof, watch-style remote has a finger ring, so your hands stay free for paddling, winging or popping up. The receiver lives in the harness battery box for a solid connection all session. Replacement watches, rings and charging cables are available.

Harness sizing

Size	Fits
S/M	71–89 cm (28–35")
L/XXL	89–114 cm (35–45")

Duotone lists the eHarness at about 3.76 kg. It floats and comes off quickly.

Care & safety

• Rinse the mast, motor and propeller with fresh water after every session.
• Keep the motor bell and propeller cover on when you're not riding.
• Never touch the propeller while the system is powered on.
• Every component is designed to be serviced yourself using Duotone's maintenance tools and screws.
• Spare propellers, motors, cables and parts are all listed under spare parts.

FAQ

Can I use my own board?
Yes. Any board with standard US foil tracks works. Duotone recommends at least 35 L.

Can I use my own foil?
Probably. The AL and Cruise masts work with Duotone, Armstrong, Axis, F-One, Gong, Lift, North, Code, Sab, AFS and KT foils using an adapter. The D/LAB mast works with Duotone and Armstrong only. See the compatibility chart.

What front wing should I use?
At least 900 cm². See our first setup guide for specific recommendations.

Is it an eFoil?
The Assist is designed to get you up on foil and then switch off. The Cruise setup is built for longer powered rides. Pair it with a Midfish Air for flat-water cruising.

Still deciding?
Email yaz@calikites.com with your weight, where you ride and what gear you have, or stop by CaliKites at 350 Hayes St, San Francisco.