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True Ames
Greenough 4A
George Greenough's 4-A — the most widely used single fin template there is: medium profile, full base, tapering flexible tip, and it works on almost any board.Sold as a single fin in solid fiberglass for a standard longboard box, in nine sizes from 6.5" to 10.5" and a long list of colours.
★★★★★5.0 (233)
In Stock
$69.00 – $110$84.00Sale
Fin SystemSingle / Longboard Box
Size
Color
Designer: George Greenough
The Fin
George Greenough's 4-A — the most widely used single fin template there is: medium profile, full base, tapering flexible tip, and it works on almost any board.
Sold as a single fin in solid fiberglass for a standard longboard box, in nine sizes from 6.5" to 10.5" and a long list of colours. It has been True Ames' bread and butter for over 40 years and is still the most popular single fin design going, because the balance in it is neutral: a full base for drive, a 50/50 foil, and a tip that tapers and flexes rather than gripping on. Longboards, mid-lengths, hulls, gliders and shortboard 2+1 set-ups all take it.
How that reads
The full base is where the drive comes from — load the back foot and the board goes. Above it the area falls away toward the tip, and the tip flexes under load, so the fin lets go at the top of a turn instead of pinning the tail down. That is the whole trick: it holds when it needs to and releases when the time is right, without being set up for either. Nothing about it is exaggerated, which is why it ends up on so many boards.
Who it suits
Almost anything with a centre box — a log, a mid-length, a hull, a glider, or a shortboard running a 2+1. The size is the real decision, not the template: the bigger sizes for longboards and more hold, the smaller ones for shortboards and mid-lengths and a looser tail.
Specifications
ConstructionSolid fiberglass
ConfigurationSingle fin
Base6.42"
Foil50/50
Made byTrue Ames, Santa Barbara CA
Sizes6.5 – 10.5
Colors9 options
Price Range$69.00 – $110
AvailabilityIn Stock
Reviews
What people say
The most iconic, functional, and versatile single fin available.
Our take
The right fin for most mid-lengths, eggs, and any single-fin log where carving matters more than parking on the nose — the template you end up measuring every other single against. It wakes a board up: real drive off the bottom, a long held arc through the turn, then a clean release. Go volan for flex through the whole fin on a heavier board, and go 4C instead if your priority is noseriding and tight pivots.
More About This Fin
The Greenough 4A is a single fin designed by George Greenough, made by True Ames, with a full base, long swept rake, tapering tip with moderate flex, and a symmetrical foil. Greenough drew the outline from the tails of tuna and dolphins. It comes in sizes from 6.5" to 10.5": 6.5"-8.5" for shortboard single fins and 2+1 boards, 7.5"-9" for speed shapes and mid-lengths, and 9"-10.5" for single-fin longboards. A volan version is also offered, which carries flex deeper through the body of the fin.
Similar Fins
Mentioned in the review — Greenough 4C · Greenough 4A Volan — not something we carry.
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Why Volan?
Volan is a woven fiberglass cloth laid by hand and finished with a resin that cures to a warm amber tint. It flexes differently than solid fiberglass — more spring, more life, more feel through turns. Where solid glass is stiff and direct, volan breathes with the wave.
The hand-laid process means each fin has subtle texture and character. It's heavier, which adds momentum through flat sections. Surfers who ride volan describe it as "warmer" — the fin does more of the work, trimming and holding without demanding constant input.
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