6.5" International 4A Center Fin - Light Blue Pro Glass.

High-performance surfboard fin crafted from solid light blue Pro Glass for ultimate 4A template firm flex and precision.

• Best For: Mid-lengths, 2+1 setups, and performance longboards.

• Feel: Firm flex.

• Conditions: All-round versatility from waist-high peelers to overhead carves.

• Compatibility: Standard Center Sliding Fin Box. (US / Bahne box)

• Placement: Center fin box. Move it forward for a looser feel, or back for more stability.

  Specs

  Height (Depth) 6.5: Base 4.9” ‍ ‍ Foil 50/50 Area 23.07 sq. inches Sweep (Rake) 38.2 degrees Aspect Ratio 1.83

  With a 38.2° sweep angle, this fin moves firmly into the High-Performance Rake category. While the height and aspect ratio suggest a balanced template, that significant tilt transforms how the board will feel on a wave.

  Here is a breakdown of the performance style:

  1. The "Carving" Specialist

  A sweep angle of 38.2° is quite high. This means the tip of the fin sits significantly behind the base.

  • The Feel: When you lean into a turn, the fin will "track" in a long, predictable arc. It resists snapping or pivoting quickly, making it ideal for high-speed, rail-to-rail surfing.

  • Hold: Because the surface area is stretched back, it provides immense "hold" in the face of the wave. You can push very hard against this fin during a bottom turn without worrying about the tail sliding out.

  2. Drive and Momentum

  The 4.9" base is relatively wide for a 6.5" fin.

  • The Result: The wide base creates a lot of "drive." Every time you pump or lean, that large surface area at the bottom acts like a lever, translating your energy into forward projection.

  • Flow: This fin is designed to maintain its speed through "flat" sections of a wave rather than generating quick bursts of acceleration from a standstill.

  3. Stability vs. Agility (Aspect Ratio 1.83)

  An Aspect Ratio of 1.83 is on the lower side (shorter and wider relative to its area).

• Drag vs. Lift: While higher aspect ratios (2.5+) are more "efficient" and faster in a straight line, the 1.83 ratio is built for control. It creates a "dampened" feel that smooths out chatter in choppy water.

• Pivot: This fin will feel "stiff" if you try to turn it in a tight space (like a small beach break). It requires a larger canvas—think long, open-face point breaks.

The Verdict: This is a "power surfer's" fin. It is best suited for a mid-length board or a stable 2+1 longboard setup where the goal is graceful, sweeping turns and maximum control at speed.

• Eveley Surfboard Fin Knowledge Hub

  Navigating the world of surfboard hardware can be complex. To ensure you’re getting the most out of your setup, check out our comprehensive Surfboard Fins Australia – Complete Buyer’s Guide to learn about foil types, cant, and rake. Understanding how surfboard fins affect your hydrodynamics is the fastest way to level up your surfing.

  Delve deeper:

• Single Surfboard Fins: How Single Fin Surfing Changes Speed, Flow & Control‍ ‍

• Single Fin vs 2+1 Longboard Setup — Which Should You Choose?

• Surfboard Fin Materials Guide – Fiberglass vs Honeycomb vs Carbon Surfboard Fins

• Sliding Center Fin Box Explained (US / Bahne box)