The Greenough 4-A Single Fin is the most iconic, functional and versatile single fin available, because it works extremely well on just about every type of surfboard. The 4-A has been True Ames' bread and butter for over 40 years now, and it is still the most popular single fin design there is due to it's all-around and well-balanced performance.
Greenough 4-A
Upright Tight TurnsRaked Drawn-Out TurnsLess Area LooseMore Area StableSpeed ControlSpeed Generating DriveLess Flex ResponsiveMore Flex ProjectionForm | Medium profile, full base coupled with a tapering & moderately flexible tipFunction | A fin that will hold when you need it to and release when the time is rightFeel | Neutral-positive, perfectly-balanced, a fin that will drive off the bottom, and have an acute responsiveness through arcing turnsOverall | Versatile - designed for all board shapes and surf conditions
SIZE
HEIGHT
BASE
AREA
6.5”
6.49”
5.42”
22.86”²
7.0”
7.09”
5.67”
24.89”²
7.5”
7.55”
5.95”
26.86”²
8.0”
8.11”
6.09”
28.85”²
8.5”
8.51”
6.42”
32.19”²
9.0”
9.14”
6.93”
36.13”²
9.75”
9.71”
7.09”
39.93”²
10.0”
10.08”
7.42”
43.85”²
10.5”
10.63”
7.91”
48.44”²
Construction | Solid FiberglassFinish | MatteFitment | Single Fin BoxApplication | Screw + Plate
The 4A is perfect in so many ways. It checks all of the performance boxes. The solid-sized base and width create stability and drive, while the rake and flexible tip enable top-to-bottom turns and maneuverability.
The Greenough 4A is a bread-and-butter fin. It allows you to feel the shape of a surfboard, it never gets in the way, with it's perfectly neutral design, when sized correctly to the board it fades away and becomes one with your surfing. It holds you tight but lets you loose, and it gives you feedback but disappears- truly the most versatile fin on earth.
The true beauty of this fin is that you can ride it in any board that has a single fin box. The larger sizes (9"-10.5") are great for single fin longboards, the medium sizes (7.5"- 9") pair well with speed shapes and mid-lengths, and the smaller sizes (6.5"- 8.5") pair well with shortboard single fins and 2+1’s (boards with side fins).
