True Ames GREENOUGH 4A Longboard Fin

Install the 4-A on any performance surfboard and you will find instant bliss.

There is a reason this is the most iconic, functional, and versatile single fin available...it works on just about anything! The Greenough 4-A has been our bread and butter for close to 40 years now and is still the most popular single fin design there is.

A truly well-balanced fin...the full base coupled with the tapering, moderately flexible tip provides a solid amount of drive off the bottom and acute responsiveness through arcing turns. Designed for both speed generation and spending time surfing in the pocket, the 4-A is a fin that will hold when you need it to and release when the time is right.

GEORGE GREENOUGH

The surf world is forever indebted to the design and performance innovations of George Greenough, a Santa Barbara native and avid kneeboarder, who is the reason why people today use high-aspect ratio fins and perform radical turns on waves that surfers in the 50s and 60s only dreamed of. 

A backyard craftsman and inventor, Greenough became known for his hugely influential board and fin designs dating back to his high school days in the early 60s where he would shape his first boards in woodshop out of balsa. Fast forward a few years and the Velo-spoon (short for velocity) was created. A short, red kneeboard with the deck scooped and a wide flex-tail. This board rocketed Greenough into the next dimension of wave-riding as it showcased a combination of design ideas to allow the types of maneuvers that inspired generations of surfers to this day. 

His kneeboards weren’t the only thing catching the attention of the surf world. The high-aspect-ratio fins Greenough created to compliment his kneeboards, a direct influence of sea creatures, took the world by storm. The likes of Nat Young and Bob McTavish took notice and soon the best of the best surfers were ditching their D-fins for Greenough’s design and in 1966, it was a direct influence on Nat’s winning of the world surfing championships and the ushering in of the shortboard revolution.

The most popular single fin of all time, the 4-A, is the bread and butter of our catalog. Its full base and tapering flexible tip make it one of the most versatile and performance-oriented single fins ever designed. The 4-C, a precursor to the 4-A, is a truly important template as it’s the closest to the original high-aspect fin Greenough invented as you can get.