SBS Fiberglass Longboard Single Fin Butterfly Model (Greenough 4-A)

In this review of the SBS Fiberglass Longboard Single Fin Butterfly Model the bottom line is simple: riders after a versatile, high-performance single fin with a classic Greenough 4-A feel will appreciate the balance of stiffness and controlled flex. Our review finds it best for longboarders who want smooth arcing turns and reliable drive without exotic tuning. The fin ships with a no-tool fin screw for quick fitting and uses semi-transparent fiberglass that gives a vintage surfboard look while keeping the fin responsive in a variety of conditions.

Key Features

• Greenough 4-A inspired template: Provides a proven balance of stability and maneuverability for single-fin longboards and logs.
• Stiff base with moderate rake: Delivers strong drive off the tail while allowing controlled, drawn-out turns on the face of the wave.
• Medium flex with tapered tip: The taper to a moderately flexible narrow tip lets the fin release predictably when pressured for more dynamic moves.
• Semi-transparent fiberglass material: High quality fiberglass offers durable construction and a classic finished look that complements many board styles.
• No tool fin screw included: The included no-tool screw and plate make installation and swapping quick and hassle free at the beach.

Who It's For

The SBS Butterfly Model is ideal for longboard surfers who prefer a single-fin setup and value smooth drive and vintage-inspired performance; it suits riders on mid- to large-length longboards and those who surf small-to-medium, clean waves. The fin's stiffness at the base helps heavier riders or those looking for a stable rail-to-rail feel maintain speed through maneuvers.

Surfers who demand super loose, skatey single-fin behavior or who require highly specialized modern quad-style responsiveness should look elsewhere. Also, if you need an exact factory-matched fit for a less common fin box type, verify compatibility since customer reports show fit can vary between snug and loose.

Pros & Cons

Pros

• Well-built fiberglass construction offers reliable durability and a pleasing finish.
• Great value given the performance, with many customers noting quality and color at a lower price than comparable fins.
• Included no-tool fin screw simplifies installation and travel setup.
• Template and flex pattern provide predictable drive and smooth arcing turns.

Cons

• Fit can vary between boards; some riders report a looser than expected fit compared to standard fins, so check box compatibility.
• Maneuverability received mixed feedback from a few customers who preferred a different flex profile.

Specifications

Our Verdict

The SBS Fiberglass Butterfly Model is a strong choice for longboard riders who want a dependable single fin that blends classic Greenough traits with modern build quality. It delivers solid drive, a pleasing finish, and good value thanks to durable fiberglass construction and included hardware. Check your fin box fit, but for most longboard setups this fin is a practical upgrade that will serve casual to committed riders well.

Frequently Asked Questions

Will this fin fit standard longboard fin boxes?
It fits most common longboard single-fin boxes, but customers report some variation in snugness so confirm your box type before purchase.

What kind of waves is it best for?
Best for small to medium clean waves where the fin can provide drive and smooth arcing turns on a longboard.

Is the included screw really tool-free?
Yes, the fin ships with a no tool fin screw and plate designed for quick hand-tight installation and easy beach swaps.