Why the Bottom Matters
Flip your board over and you’ll find its bottom contour—the shaping of the underside that controls how water flows beneath you. Thanks to the Coanda Effect, water sticks to these curves, meaning the contour design directly influences your speed, grip, and maneuverability. Shapers mix and match concaves, Vs, and flats to give boards unique performance traits.
Types of Bottom Contours
- Concave: Creates lift and speed by channeling water straight to the tail. Great for small-wave speed boards and big barreling waves where drive matters most. Downsides: can feel stiff, requiring strong back-foot pressure to turn.
- Convex (or belly): Encourages smooth rail-to-rail rolling, making turns easier. But adds drag, making it slower and less stable at high speeds.
- V-bottom: Splits water toward the rails, sacrificing lift for lightning-fast transitions. Perfect in powerful waves but can feel bogged in weaker surf.
- Flat: Neutral baseline—neither fast nor slow, maneuverable nor stiff.
- Double Concave: Adds speed while softening the “tracking” feel of a single concave, improving responsiveness.
- Channels: Cut into the tail, they enhance drive and hold—like adding extra bite without a bigger fin.
Most boards use combinations: concave up front for speed, double concave mid-board for balance, and V near the tail for quick direction changes.
How TRAX Helps You Read Your Board’s Bottom
Looking at contours tells you what a board should do—but TRAX shows what it actually does for you. By tracking speed, turn angles, and flow, TRAX reveals whether your single concave really makes you faster, or if that V-bottom is improving your turns. With objective data, you’ll know which contours enhance your surfing, and which are just marketing.
Related Reading
- How to Break Down Surfing and Actually Progress
- How to Catch More Waves in Crowded Lineups
- Fix Your Surf Stance – Without Getting in Your Head
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