Upright Twin Fins — The Complete Performance, Design & Setup Guide
Twin fins are among the oldest high-performance surfboard fin configurations, yet they remain one of the most misunderstood.
Within the twin-fin world, the upright twin template stands apart as a distinctly modern evolution:
faster than a thruster, tighter than a classic keel, and far more controlled than early twins.
This authority guide explains everything surfers need to know about upright twin fins, including:
How upright twins differ from keels and raked twins
The hydrodynamics behind twin-fin speed and release
Why upright templates dominate modern twin performance
How to match upright twins to board type, waves, and surfer weight
Real-world setup tuning for maximum speed and control
What Are Upright Twin Fins?
An upright twin fin is defined by:
Reduced rake (more vertical outline)
Moderate base length for drive
Balanced tip area for release and pivot
Compared to long, sweeping keel fins, upright twins:
Turn tighter
Release faster
Feel livelier under the back foot
They preserve the down-the-line speed twins are famous for while adding modern manoeuvrability.
Twin Fin Hydrodynamics Explained
Twin fins behave differently from thrusters because they:
Reduce drag (fewer fins in the water)
Increase rail engagement
Allow controlled tail release
This creates the signature twin-fin sensation:
Effortless speed with skate-like freedom.
But early twins had a weakness:
lack of control in steeper or powerful waves.
The upright twin template was the solution.
Why Upright Twins Changed Twin-Fin Surfing
Classic 1970s twins used:
Long keels
Heavy rake
Large surface area
These produced:
Incredible trim speed
Smooth drawn-out lines
Limited vertical turning ability
Modern surfers demanded more:
Sharper direction changes
Pocket surfing capability
Control at higher speeds
By standing the fin more vertical, designers achieved:
Faster rail-to-rail transitions
Tighter turning radius
Cleaner release at the lip
This transformed twins from retro specialty boards into serious performance equipment.
Upright Twins vs Other Twin Templates
Keel Twins
Feel: smooth, fast, drawn-out
Best for: retro fish, small waves
Limitations:
Slow turning response
Hard to surf vertically
Raked Performance Twins
Feel: powerful, carving-oriented
Best for: open-face waves
Limitations:
Less pivot in tight pockets
Upright Twins
Feel: fast, loose, highly manoeuvrable
Best for: modern fish, performance twins, varied surf
Key advantage:
The best balance of speed, control, and release.
Board Types That Benefit Most
Modern Fish
Upright twins give fish boards:
Faster direction changes
Better pocket surfing
Control in steeper waves
This is why many contemporary fish designs now favour upright templates over keels.
Performance Twin-Fin Shortboards
On refined twin shapes, upright fins deliver:
Thruster-like turning ability
Twin-fin speed
Looseness without instability
This category represents the fastest-growing fin setup in modern surfing.
Mid-Length Twins
For 6'8"–8'0" twin boards, upright fins provide:
Hold through longer rail lines
Control at higher speeds
Clean projection out of carving turns
Material Influence on Upright Twin Performance
Composite / Honeycomb
Light
Quick response
Slightly stiffer feel
Good for small-wave speed.
Solid Fiberglass (Pro Glass)
Smooth, predictable flex
Strong drive through turns
Long-term durability
Preferred for:
serious, everyday twin-fin surfing.
Fiberglass maintains control at speed, which is critical for upright templates.
Choosing the Right Upright Twin Size
Around 5.3"–5.6"
Looser
Best in small waves
Suits lighter surfers
Around 5.6"–5.8" (Performance Sweet Spot)
Balanced speed and control
Works across most waves
Ideal for modern fish and performance twins
This range represents the true everyday upright twin size.
6.0"+ Upright Twins
More hold
Better in powerful surf
Suits heavier surfers or larger boards
Trade-off:
slightly reduced looseness.
Wave Matching for Upright Twins
Small, clean waves
Exceptional speed and glide.
Easy acceleration without pumping.
Shoulder-high surf
Where upright twins truly shine:
Fast pocket surfing
Smooth cutbacks
Confident lip release
Overhead waves
Still viable when:
Board design supports control
Fin size is adequate
Construction is strong (fiberglass preferred)
Setup & Tuning Tips
Fin Position
Because twins lack a center fin, placement matters more:
Forward placement → looser, skatey
Back placement → more hold and drive
Even 5–10 mm changes are noticeable.
Pairing With Trailers or Stabilizers
Some boards add:
Micro trailer fin
Small nubster stabiliser
This creates a “2+1 twin” hybrid feel:
Extra control
Slight drag increase
Reduced pure twin freedom
Most surfers prefer true twins first, then experiment.
Real-World Feel of Upright Twins
Surfers consistently describe upright twins as:
Fast without effort
Loose but predictable
Capable of vertical surfing
More alive than thrusters
This blend explains their rapid rise in modern performance surfing.
Why Upright Twins Define the Modern Twin Era
Surfboard design moves in cycles, yet upright twins persist because they solve the core twin-fin challenge:
How to keep the speed…
without losing control.
They succeed by delivering:
Twin-fin glide
Shortboard manoeuvrability
Reliable hold in real waves
No other twin template balances these forces as effectively.
Final Verdict
The upright twin fin is no longer a niche retro option.
It is now one of the most versatile high-performance fin designs in surfing.
For surfers seeking:
Maximum speed
Tight turning freedom
Smooth fiberglass drive
Real-world versatility
Upright twins represent the modern benchmark.