Wavegrinder fin review

After buying my new 10'0" Bing Silver Spoon, I was faced with the fact that the Bing #1001 pivot fin wasn't the right match for knee to waist mush in VA. The board was unstable when walking to the nose and slow. So, I set out looking for a new fin. First, I purchased a Greenough 4A. It worked better, but I started wondering about unconventional fins. I considered the Star Fin, the Turbo Tunnel, the Spitfire & the Wavegrinder. I was looking for catchability & speed, which meant the lowest drag possible. That disqualified the Star & the TT. Despite the Spitfire's lack of vortex, the design leads me to the conclusion that it may have more drive, but a Wavegrinder of of equivelent length is faster in the straight line. I am not an affiliate of Wavegrinder in any way & will attempt to comment as objectively as possible.

The fin: Cleanly manufactured with the impression of precision. No flashing or extra plastic from the molding process. I do question, however, the manufacturer's claim of being "bulletproof". I do not believe the Wavegrinder's material will sustain the impact of a bullet better than (or as well as) fiberglass of the same thickness. One thing that I did notice was: With all of the attention to detail in the final product; the fillet in the front at the root; the Nasa-inspired foil; the rake & winglet design...after all of that, they place a non-countersunk round metal screw on the front side that shadows the fillet!

The conditions: As Doug Simpson (the owner) suggests, I compared it with my current fin (the 4A) in a back to back test during a single session. The waves were knee to waist-high and slightly weak. Shortboarders would stall after the initial bottom turn. Longboarders were fairing much better.

Placement: The owner's suggested placement was 2" back from the normal placement of my current fin. Unfortunately, I didn't have a "normal" placement for the 4A fin. It had only been out twice and it was about 2/3s back from the front of the box. The only concern here was that the winglets of the Wavegrinder would create drag from being parallel with the significant kick in the Silver Spoon's tail. This kick created an upward angle in the tail that was matched by the winglets, pointing them downward in the front. Out of concern of this, I placed the Wavegrinder 1" back from the center of the box instead of 2" behind the former fin's placement.

Comparison: The 4A fin paddled well. I did not feel what I perceived to be drag during paddling. I caught most waves with good amount of hard paddling and proper placement. Early take-offs were not an option. The board turned well and trimmed predictably. Not a disappointment, by any means. After the suggested five waves with the 4A fin, I installed the Wavegrinder as mentioned above. I immediately noticed a looseness in the board paddling out past the break. I also noticed a marked increase in the speed of paddling with the same effort as the 4A. I am not convinced that the ability to catch the waves was increased, however, the board certainly moved faster once it was underway. As I expected, the straightline speed was there. I've read other postings, saying that the board was loose, but had drive at the same time and could not understand this description. The best way I cand describe the board's drive is that the board doesn't respond to small corrections, but when you make a hard turn, it drives. My reaction to this is the desire to carve, so I did. I was able to lean it hard on the rail and throw a spray. I fell over, however, and have no idea if I could've continued the ride or if it would've stalled. I was surprised to find that walking to the nose was more stable with the Wavegrinder than the pivot fin. I have not gone to the nose on the 4A, so I can't make that comparison.

Final impression/comments:
1. Overall, The Wavegrinder is an exciting concept fin with a lot of potential. My initial impression is that this fin is most appropriate for single-fin longboards on fast beach break/sandbar waves that are at least waist-high. My honest opinion is that this fin needs speed for drive and will probably be better suited for carving in waist to head-high waves. Smaller than waist, it's good for going straight and fast. Bigger than head, I have a feeling it will stall and spin out hard. That is just an opinion.
2. The set screw needs to be countersunk...plain and simple.
3. The winglets need to take in account that every longboard has an amount of tail rocker. This should be averaged out among the most popular longboard designs and applied to the winglet caster.

I will post again when I have a few more sessions. Pics to follow.

 

Disregard placement. I moved the fin rearward after pic.

 

Thanks.

As far as the Turbo Tunnel, I've never used one. I see reviews from guys that use them and like them. I also see reviews from guys that don't like them. Usually, they haven't ridden them.

Because I'm speed-oriented with an emphasis on catching small/weak waves, my point of view is biased, but here it is: If I believed that it was possible for the Turbo Tunnel's design to provide more speed due to it's design, I would consider trying one. My opinion, however, is that the added surface area results in more drag without any speed benefit based on physics design.

That being said, I also believe guys that are looking for more drive, get it with a properly aligned Turbo Tunnel fin. With this in mind, I would try it in a longboard if I were riding a slow/consistent wave like Malibu or barrelling waves in which you were trying to remain shacked.

 

Unfortunately, it looks like it may be a while for those follow up sessions.