Assist Slim is Foil Drive’s lightest, performance-focused system, designed to preserve the weightless, natural feel of foiling while providing powerful bursts of thrust to help you get onto foil.

Built for riders who prioritise responsiveness, agility, pumping and minimal drag, Assist Slim is designed primarily for foil-assist riding.

The Slim delivers the same peak power as Assist MAX in a thinner, more compact system, allowing experienced riders to enjoy powerful acceleration without adding unnecessary weight or drag to their setup.

Rather than providing continuous propulsion, Assist Slim is designed to deliver short, powerful bursts to get you onto foil, after which you can transition to unpowered riding and pure glide.

It is particularly well suited to:

• Pumping
• Wave riding
• Wind swell
• Wake
• Light-wind winging
• Experienced riders who prioritise responsiveness and agility

Key Features

Lightweight & Agile

Assist Slim is designed to minimise system weight while maintaining strong peak performance.

With a minimum installed weight of approximately 3.75 kg, Slim is Foil Drive's lightweight performance option for riders who want their foil to feel as natural and reactive as possible.

Efficient Power

Slim is designed around short, efficient bursts of power rather than continuous motor assistance.

Use the motor to accelerate and get onto foil, then transition to unpowered riding for a natural foil experience.

Assist Only

Assist Slim is optimised for foil-assist riding.

Its compact design and low weight make it particularly effective for riders who want to maximise:

• Pumping performance
• Glide
• Carving
• Responsiveness
• Manoeuvrability

Ultra-Light

Depending on the battery configuration, Assist Slim can achieve an installed system weight of approximately 3.75–4.25 kg.

The exact weight depends on the battery and motor configuration selected.

Ideal for

Assist Slim is particularly suited to:

• Pumping
• Wave riding
• Wind swell
• Light-wind winging
• Wake foiling
• Riders who want minimal drag and weight

Best Choice For

Assist Slim is the ideal choice for riders who prioritise:

Responsiveness • Agility • Low Weight • Pumping • Natural Foiling

Key Specifications

*Minimum installed weight is based on the Slim Performance Battery configuration.

Building Your Assist Slim System

The Assist Slim is sold as a Base Kit where you can select the components that best suit your riding, or a Complete Kit.

Assist Slim

The Slim Electronics Box forms the core of the system and provides the compact, lightweight platform that the Slim system is built around.

Motor

Compatible with all motor and propeller options for maximum flexibility.

Battery Options

Assist Slim is compatible with multiple battery options:

• Slim Performance Battery (40V)
• Slim Endurance Battery (28V)
• Slim Travel Battery (40V)

Each battery provides a different balance of weight, capacity and runtime, allowing you to optimise the system for your riding style and travel requirements.

Charger

The charger required depends on the battery selected:

• 28 V Charger (Endurance Battery) - Sold Separately 
• 40 V Charger (Included with Base and Complete Kit options)

Always use the charger specified for your battery.

Slim Battery Options

Slim Performance Battery

The Slim Performance Battery is designed for riders who prioritise the lightest possible setup and strong bursts of power.

It provides the minimum installed system weight of approximately 3.75 kg when paired with the Assist Slim system.

This makes it particularly well suited to:

• Pumping
• Surf foiling
• High-performance riding
• Riders who prioritise minimum weight

Slim Endurance Battery

The Slim Endurance Battery provides additional capacity for riders who want longer assisted sessions while retaining the compact Slim system.

It is a good choice when you want to balance:

Low weight + extended runtime

Slim Travel Battery

The Slim Travel Battery is designed with travel and portability in mind, providing another option for riders who need a compact and convenient system.

Compatibility

Assist Slim is part of the Foil Drive Gen2 ecosystem.

The system must be configured using compatible:

• Slim Electronics Box
• Nose Cone C and D
• Slim battery (Performance, Endurance, Slim Travel)
• Correct battery-specific charger (40V and 28V)
• All motor options are compatible with the Slim System
• V2 and V3 controller compatible with the Slim System

Do not assume that batteries or chargers from other Foil Drive systems are compatible with Assist Slim.

Always check the voltage and compatibility requirements of the specific battery and charger before connecting them.

FAQs

Is Assist Slim an e-foil?

No. Assist Slim is designed as a foil-assist system.

It provides short bursts of motor power to help you get onto foil, allowing you to transition to unpowered riding, pumping and gliding.

How powerful is Assist Slim?

Assist Slim produces up to 26.5 kg / 58.4 lb of peak thrust, with a peak power-to-weight ratio of approximately 7 N/kg.

Peak power is approximately 1,854 W / 2.5 hp, with sustained power of approximately 1,455 W / 1.9 hp.

How light is Assist Slim?

The minimum installed weight is approximately 3.75 kg / 8.26 lb when configured with the Slim Performance Battery.

Depending on the battery configuration, a Slim system can weigh approximately 3.75–4.25 kg.

What battery options are available?

Assist Slim can be configured with:

• Slim Performance Battery (40V)
• Slim Endurance Battery (28V)
• Slim Travel Battery (40V)

Battery capacity across the compatible Slim range is approximately 166–241Wh.

What charger do I need?

The charger required depends on the battery.

Slim batteries use either a 28V or 40V charger, depending on the specific battery configuration.

Always use the charger specified for your battery.

What is the water rating?

The Assist Slim system has an IP68 water and dust resistance rating.

Correct care, rinsing and maintenance are still essential after every session, particularly following saltwater use.

Can I use an Integrated Mast with Assist Slim?

Yes, where the Integrated Mast is compatible with the Slim system.

This is one of the reasons the Base Kit is available without a separate motor — riders purchasing an Integrated Mast do not need to purchase a second motor.

Who should choose Assist Slim?

Assist Slim is best suited to riders who prioritise:

• Minimum weight
• Responsiveness
• Agility
• Pumping
• Wave riding
• Natural foil feel
• Short bursts of assistance rather than continuous power

If you want more sustained motor power and longer powered riding, a Fusion or Assist MAX system may be a better fit.

How does the Slim compare with Max and Gen2.5 systems?

Slim prioritises minimum weight, responsiveness, pumping and agility.

MAX provides more thrust and significantly more battery capacity than the Slim, making it better suited to riders who want longer sessions, more assistance and greater versatility across different conditions.

Fusion provides the longest run time, more thrust and sustained power across the whole voltage range of the battery. The Fusion is best suited to riders over 100kg or those wanting to use the system as an e-foil alternative.

Max+ keeps what you love about the Gen2 Max, but is packed with all the extra features of the Gen2.5, including more thrust, more battery options and safety features.

If your priority is minimum weight and natural foil feel, choose Slim.

If your priority is power, runtime and versatility, choose MAX.

If your priority is power, runtime, versatility and you're over 90kg, choose Fusion.

If your priority is power, runtime, versatility and you're under 90kg, choose Max+.

To compare our systems side by side, click here to see the Compare Page on the website.