North Sonar Surf Hydrofoil Series

680cm2 | 830cm2 | 930cm2 | 1080cm2 | 1230cm2

Ideal for riders wanting more from surf and downwind swells (with or without a wing). The foil’s insensitivity to angle of attack change means you don’t have to be an expert or have perfect pumping technique. A refined balance of roll stability and manoeuvrability gives you confidence during pumping and take-offs, and the ability to initiate powerful rail-to-rail carves. Push it harder, lip stall and lay down banking turns, knowing tip ventilation is a thing of the past. Reduced distance between the mast and front wing makes for faster, tighter pivoting turns. North have kept the span similar between the three sizes, providing the same ride feel across the entire size range. The SF promises a frictionless sensation of glide at slower speeds. Responsive and agile. With intuitive recovery. Wakesurfing ten waves back, prone-surfing, wing-surfing, pumping or mastering the downwind. The Sonar SF Series. At one, with it all. show less

Features

• Low stall speed
  
• Effortless pumping
  
• Surf-style turning (smooth rail to rail and surf yaw snap)
  
• Composed glide
  

Materials

• Pre-Preg Carbon
  
• Titanium Screws
  

**TECHNOLOGY

Progress faster
Moderate anhedral rondure combines with a gentle back-swept plan shape combine to create a good balance of roll stability, for confidence during pumping and take-offs, and manoeuvrability, for initiating turns with ease.

Effortless pumping
To maintain an efficient window of operation at the lowest pumping speed, we needed to generate more lift out of the foil section. We always try to balance drag vs lift – so to find that compromise here, we shifted the the peak in the lift-to-drag ratio to the lower end of the speed range. Having more profile thickness and curvature in the front section of the profile makes it less sensitive to angle of attack changes. At the opposite end the HA Wings have a flatter section at the front, which makes it more sensitive to angle of attack changes. They are high speed, but easier to stall.

Composed glide
The SF can be compared to a high-aspect wing – only at lower speed. Our Sonar HA wings have a phenomenal glide at a higher speed, but you need to maintain it somehow. Because we love that frictionless sensation of glide so much, we’ve engineered the same glide into the slower speeds SF-Front Wings.

Responsive turning
We’ve moved the wings as far back on the fuselage as possible for a better turning response, so you may need to move the mast further forward on the track compared to other North wings. Mounting the front wing closer to the mast reduces your yaw stability, so you can initiate turns more easily.

Match with S215 Stabilizer
Because the front wing can operate at such a high-angle of attack without stalling, you need a stabilizer that does the same. With smaller front wings, you want to upgrade to a smaller stab, but it’s important to match the stall speed. The S215 was created with lower stall speed to complement that of the SF front wings.

FRONT WING	ACTUAL AREA (cm2)	WINGSPAN (mm)	ASPECT RATIO	RECOMMENDED STABILIZER	ITEMS INCLUDED
SONAR SF680	680CM2	790	9.2	S185 Stabilizer	SF680 Wing, Cover, Screw Pack H (M8x23mm)
SONAR SF830	830CM2	865	9.0	S185 or S215 Stabilizer	SF830 Wing, Cover, Screw Pack D (M8x25mm)
SONAR SF930	930CM2	900	8.8	S215 Stabilizer/td>	Wing, Cover, Titanium Screw Pack D (M8x25mm)
SONAR SF1080	1080CM2	915	7.8	S215 Stabilizer	Wing, Cover, Titanium Screw Pack D (M8x25mm)
SONAR SF1230	1230CM2	930	7.1	S215 Stabilizer	Wing, Cover, Titanium Screw Pack F (M8x30mm)