Are you transfinbic?

I think it's pretty cool that twin fins and keels are finding their way back into the lineup. Back in the day they were high performance grovelers. Now they're a versatile arrow in a quiver.

But yeah, thrusters are the mainstay. Quads are closer now, but 3 fins are the daily drivers

 

So. Who's the many that's got you worried about thruster set ups on grovlers? I won't grovel

 

I know the 5-fin setup isn't made to ride with all 5 fins, but I want to know who's tried this and what it felt like

 

The nub acts adds a bit more drive (although to me, not really discernible) but what I think it really does is allow the quad to go rail to rail a bit smoother. I experimented a few times in the same session with and without the nub, and that was the only thing I felt different. Some people say it's a "stabilizer"... I didn't notice that either, even after deliberate experimentation, paying attention and LOOKING for that sensation. I thought MAYBE a touch more drive through turns, but DEFINITELY a smoother "rolling" sensation when going rail to rail with the nub in vs. without it.

Quads on grovelers make sense to me. A second set of single foiled fins toed and canted can almost double the amount of thrust and lift compared to the thruster. The center fin only adds directional stability and drive... no lift. Quads add 25% more fin area, and that makes a difference.

I've never NOT had a twin or fish in my quiver... ever. A different feel completely, and IMO not a substitute for a good groveler.

 

Yeah I've seen guys using the nub, but not for a few years now. I think they have a reputation for not doing much at all.

I know I could probably go to Swaylock's and find threads to give me answers to my questions, but I like keeping it local and hearing what average Joe's have to say. Besides, it's good content and this place could use some.

Since the nub hasn't really had any intended effect other than taking hard-earned $$$ out of the pockets of curious surfers, I'm wondering if another style or size would ever work, or if 5 fins of any style or arrangement is just clogging up the works.

I remember thinking that about the Thruster for a minute back in '81.

 

Lets talk Longboard fins. High performance board set ups vs nose riding. What's the best fin for each.

For me I've been focusing on nose riding so I've got a 9'0 single pivot fin 9 inch. I find I get plenty of turn and the ability to lock it in the wave. Good bottom turns. The board is poly

 

the nubster is useful. on mushy/higher tide surf, swap it out with the center fin and you get a much looser board with just a little bit of hold, for a bit more wiggle on the slow spots...doesn't quite spin out the way it would with no center fin at all.

 

I’m having a twin shaped right now and grabbed a set of these wild looking keels to go with.

Almost everything about this board is local: Shaped by one of my old friends, Fins designed locally and the the fin guy is glassing the board. Even the epoxy resin was developed by a professor here in town at my alma mater.

ETA for delivery of the board is 4/20

 

Nice fins.. What's a alma matter ?

 

The university from which I received a very expensive piece of sheep's skin.

 

La Piedra , a true 5 fin defeats the ride of a quad with that nub . Digressing with LB , fins dont create lift , they produce cavitation which creates drag . Adding more cav negates thrust .

 

Antione , I cluster a cutaway up in the box with a pair of Pancho s L . A great setup for good waves with thrust and shortening the turning radius .

 

Sweet set up on the fins. I never thought of that so I will put it to the test. Thanks for the info and pic

 

The board in that pic has a lot of foil and tail rocker to be a longboard, I'm guessing 2+1 mid-sized?

 

Here's my understanding... A single foiled fin (convex on one side, flat on the other) must create a lifting force in the direction of the curved surface. We know that as the velocity of a fluid increases, the pressure decreases and an imbalance of forces is created. So a canted fin creates a lifting force that is both railward and upward... and if toed, also creates forward thrust.

Going down the line, a well foiled fin reduces the chance of cavitation and typical board speeds. Even a well foiled fin will cavitate at high speeds, but those speeds are not typically reached on surfboards, even in big surf. A poorly foiled fin, however, will most definitely cavitate at surfing speeds, and you'll often hear the fin hum as a result. You'll also feel the board "put on the breaks" too... cavitation creates enormous drag.

All fins create drag. That's why they work. Keep in mind that drag... the force that opposes motion... is what we rely on to turn. All fins drag AND cavitate through a turn. The goal is to create a fin that has efficiency down the line and functional drag through turns.

 

I know nothing of physics, and I have a hard time understanding the theories.

So if canting and toeing creates thrust and lift, why do double foiled keels set perfectly in line with the stringer seem as if they go much faster? Though making turns is noticeably stiffer.

You might have to dumb it down a bit for me to get it

 

BAM KNOWLEDGE!
I just learned more about fins than I thought possible. Now that my brain hurts ima show off my knowledge to my dumber friends!

 

La P , HPLB , 9 ft , thin at 2.625 which is his standard thickness and needs tad more glass .