The Next Advancement in Single Fin Performance
The Power Blade, a George Greenough design, has revolutionized the modern Single Fin surfboard bringing it on par with the performance attributes of the Thruster without losing the ability of flat out trim speed that makes single fin surfing unique.
Early beginnings, George was originally inspired by Power Blade thinking in 1960 by John “Ike” Eickhart’s V- Slot fin. During the “D” fin era the large slab style fins were stiff. The vee slot cut the base away, which reduced resistance and allowed the head to move more freely making Ike’s boards faster and freer than most. George made several variations of these for the balsa spoon he made in wood shop at school.
Although George’s focus shifted during the mid 60’s to 70’s to the high aspect ratio tuna style fin we all still use today, as windsurfing became popular during the 80’s into the 90’s, George found that the slender tipped design had limitations under severe loads during high winds. Remembering the vee slot design, he then moved to develop the next version with a narrow base and large head design he called paddle fins at the time. George had great success getting better turns and more hold and speed out of this new approach. By the late 90’s George had fashioned a number of variations of the paddle fin, many of them from reworked scraps that came out of Chuck Ames’ box of reject fins!
Fast forward to the new millennium, and young Australian Pro Surfer Ellis Ericson has taken to sitting at the feet of the master and wants to try these strange narrow legged fins. George gave him a series of shapes and sizes to try, making Ellis the first official test pilot. Once Ellis hit a magic fin, George laid up the first panel using epoxy and some industrial cloth that was lying around and made the first prototypes.
Although this design is best suited to the Edge Board bottom, a tri-plane hull with a deep concave center (see Chapter 7, Close to the Edge, in “The Gift” by Marc Andreini). The advantages are quickly realized within a few turns. First off, a conventional Single Fin board design uses a flat tail rocker to make the board run across the wave during trim, so most of your speed comes from trimming along on the straighter or flattened out bottom rocker. It requires a lot of skill to get additional drive by turning as the Single Fin has a lot of area and depth and can be stiff unless it has a bit of flex. Also the flat rocker keeps the board going across the wave and draws less vertical lines. This is the single fin approach basically.
By contrast, the Thruster has shallow fins, which release water quicker along with a lot of tail rocker or lift to compensate for the center fin being on the tail (anchor fin). This gives quick thrusting style turns that are more vertical now that you have tail lift. So no trimming. You must keep turning to keep the speed up.
The Power Blade solves the problem by having such a narrow base on a straight-bottomed board. You can run in flat out trim or pull the board straight up the face with the drive of a Thruster during a hard turn if you wish or simply hold your line and draw a long bottom turn with plenty of drive.
Here is why it works so remarkably: the narrow base makes the water pressure along the base of the fin almost non-existent. It allows the rider to pull the board up or across the wave due to the small amount of resistance where the base of the fin is attached to the board.
Second, the Power Blade is designed to twist from side to side which gives you propulsion the way a fish drives itself through the water by twisting its body and fins back and forth.
When the head twists, that gives your board variable tow-in similar to a Thruster, which allows the tail to step out slightly so the tail will follow the nose. This function gives the board more drive.
These fins are made from high grade tooling epoxy and unidirectional cloth. They are sturdy enough to last a lifetime.
The original hand built prototypes created by George Greenough from the first panel he laid up became two identical sets, one for myself and one for Ellis Ericson. (Please see surfermag.com and look under Design Forum, Mid-lengths, RVCA Vimeo with Alex Knost and Ellis Ericson to see how they perform on film.)
After one full year of testing in all conditions both Ellis and I have noted that we are unable to spin them out. We get huge amounts of speed and drive out of our boards and no failure in any of the materials.
Chuck Ames of True Ames Fin Company has taken my set of Greenough made fins and measured the twist patterns; he has sourced out the materials required and set up his factory in Goleta to produce them. His replications have been sent to me and Ellis and we give them the stamp of approval!
In conclusion, although the Thruster took surfing to a higher performance level (following Single Fins) with more speed and quicker responsiveness, we lost a lot of flow, trim, deep bottom turning and down the line style that went with single fin style surfing. Now we can take that style and up the performance to match the speed and virility of the postmodern board without sacrificing the flow.