Quad Fins for Summer

[nomastomas]

With summer here and small surf prevalent, I’ve made some adjustments to the fin set up on my TBG4 Quad. Fin maker True Ames has just added a 2.6” x 2.6” asymmetric foiled (flat on one inside, curved on the other), single-tab (FCS) fin to its inventory. For waist-high or smaller waves I use a TA SB 3.25” in the front position and the TA SB 2.6” in the front slot of the rear box. The SB 2.6 is a very upright fin, and less rake in a fin yields more pivoty turns. Using the front slot reduces the size of the fin pod, again favoring tighter turns.

True Ames offers six side bite sets in sizes ranging from 2.6” to 4.6” specifically to meet the needs of quad-fin and 2+1 surfers (they also make the “Nubster” micro center fin). What’s more, you can order directly from the factory in Goleta, CA via their online store.

I had the opportunity to ride this set up in 2’-3’ surf at a local point break. Early evening, high-tide windswell, with no one out, so plenty of waves for a good trial. Results: just not enough hold. Felt more like riding a body board. On a steep face, right at the moment when the fins should dig in and create forward speed, the board would drop down the face 4”-6”. I had to apply the crank-up-on-the-beachside-rail technique on the steeper drops. Not the ride I’ve come to expect with the TB. Pushing nearly 200 lb in wetsuit, the 2.6” x 3.25” quad was just not enough fin for the desired performance.

[rodndtube]

The pivoty small fins are set inside so far from the rail that my first reaction is not being surprised. The obvious question is whether you have tried swapping out positions of the forward and aft fins. My gut says it might work better.

[nomastomas]

No, I haven't tried the rear tab of the box, but I don't think it would work noticeably better. It is only an 1/8" or so closer to the rail, and would move the leading edge further from the trailing edge of the front fin. The rear box is set 2" from the rail (measured from the trailing edge of a 3-1/2"-base fin) and toed-in 1/8". This allows 1-1/2" between the fins allowing sufficient flow between them. Even if set right on the rail, I don't think the small, upright fins would have the "grip" I like. A better solution for small days would be using a 3.25" fin on all four corners, or to replace the quad set-up with a 3.7" twin set, using just the front box.

[rodndtube]

Sorry, my bad in communicating. My thought was to swap the large fins to the rear boxes and the small pivot fins to the forward boxes. I used a similar configuration on my Bonzer paipo setup as I was working my way downward in total fin mass and total fin base (albeit I do have a 4.5 center fin which was down from the original 6" and then 5.25 True Ames center fins).
http://mypaipoboards.org/forum3/downloa ... d=1182&t=1

My trials with Knubster fins replacing the small vertical side bites was a step forward. Now I am using a set of 4 small Bonzer runners.

[nomastomas]

After installing the fins, the thought occurred to me that reversing the fin position would result in something very close to a "twinzer" set-up. However, the TBG4 is designed to have the largest (most fin area) fin on the rail at the "hip" in the outline where the "rubber meets the road" so to speak. In a twinzer set up, the much smaller front fin serves to clean up the water flow around the larger rear fin, increasing its efficiency (improving lift). To do so, its trailing edge slightly overlaps the leading edge of the larger fin. I'm about an inch off that.

As you may recall, I experimented with the quad bonzer fins on the TBG2, but didn't use a center fin. (Center fins on stand up boards reduce roll as well as provide direction. Multi-finned belly boards require neither; rider has an extremely low center of gravity and rail fins provide enough direction.) I think your're going in the right direction by reducing center fin depth. I often thought a center fin shaped like a 3-fin Bonzer runner (short but long base), but symmetrically foiled would work well on a belly board with Bonzer side-runners and Bonzer concaves (what I call open concaves)

[rodndtube]

I am a long time center fin guy... really hard to break certain habits But, I tend towards the shorter, conventional center fins. My current quad Bonzer runner setup is all small Bonzer runners, not the large and small which were too turning restrictive for me. Despite the contrariness of using a pair of Knubsters in the forward runners setup they did work very well and will serves a inexpensive pair of backups in the event of a "reef event" with the more expensive Bonzer runners.

Someday I may try a Knubster in the center slot and see what happens.

[jbw4600]

It looks to me like you fins might be little far too forward for the size of the board. Even thought the hips might be up a little way on the board, the torque (???) or leverage is further back. But I have never had a quad fin board. I thinking about going quad on longer a board (4' 6")I going to build for the winter.

[bgreen]

I'd also suggest exchanging the fins around, small up front. Twins might be worthwhile. Having said that fins drive me mad - I''ve still not got the bonzer fins tuned. Still you've got a good excuse to go surfing more.

Bob

[nomastomas]

jbw...for me, its not the board's length per se that determines fin placement but the point at which the rider can exert maximum pressure. Stand-up riders apply pressure with their feet, so fins are set towards the tail. Kneeboarders apply pressure through their knees and ankles, so they place their fins much further up from the tail. I use my hip to weigh the rail when turning or setting a line across the wave face. So, I've designed the board to have the wide-point of the outline at the point where my hips are located, while riding in the position of maximum planing. This wide-point creates a bump or "hip" in the outline, which is the point of maximum contact with the wave face. It also becomes something of a pivot point for turns. Placing the fins at this wide-point helps to insure that this part of the rail is pulled into the wave face (the "lift" generated by asymmetrically-foiled fins is not in a vertical/up direction, but rather in a horizontal/sideways direction). Because of this design feature, each TBG4 is custom built based upon rider height/length.

[soulglider]

nomas, "Stand-up riders apply pressure with their feet, so fins are set towards the tail. Kneeboarders apply pressure through their knees and ankles, so they place their fins much further up from the tail. I..." your THEORY, your comments are a generalization. not all standups put the fins far back (displacement hulls are pretty far forward), not all kneeboards have the fins farther up (aussie trickster style boards are up, carvy style cali-boards are on the tail) and YOUR boards are designed with the wide point under your hips but, not all belly/boogie/body boards are made this way and i know, you didnt say they were. boards have been made and designed with the wide point at various places, each designed to promote certain type of ride or fit a certain type of wave. check out all the poob's boards for sale just for some comparisons. everyone likes something different, we all have a different gen-code, designed by a gen-master...FUN with FINS!

[nomastomas]

SG…Aside from leaving out reference to that obscure, functionally one-dimensional design known as “the hull”, which has obviously upset you, I’m not sure what your point is here. It is obvious that my remarks are solely directed at my own designs. I want others to know that with my designs, there is an “intention” behind each design feature, in this case fin placement. I want people to understand why my design works (or doesn’t work, for that matter). Some builders are satisfied with just replicating an existing surfboard design in a reduced proportion, hoping/claiming that it works. That’s not me. And just to be clear, I have never held that my designs are the only belly/body board designs that work, or that they are the “best” designs. I’ll leave that opinion to anyone who has ridden one of my boards.

[bgreen]

I look forward to hearing what you find works. Having said that there are lots of ways to ride a wave.

Bob

[nomastomas]

More chest-high to shoulder-high groundswell at C St. today. Back to the 3.7 x 3.25 quad, and order has been restored to my universe. I got a couple of nice, long, uninterrupted rides. I love how the board holds into the face on a late take-off. I spun and went on a sneaker set wave that everyone around me was scratching to get over (main reason I got the wave to myself). Very crowded, I spent a lot of time dodging a variety of surfcraft, getting dropped on, exchanging pleasantries, etc. At times I felt like I was playing Frogger. Most weekenders have no regard for surf etiquette, or endangering the safety of others. True surf desperados, they just want to get their wave count. Yeah, I should know better...I hate it when the swell arrives on the weekend. I need to find a less popular summertime break, if that's even possible. I may have to adopt a "no corners, no crowd" approach. Prone boards are great for that, if you don't mind the inevitable whuppin' at the end of the ride. I'm anxious to try a set o 4.0s or 4.35s in the front position if I can get some head-high waves. Maybe later this summer...maybe during the week...maybe...

[soulglider]

SG…Aside from leaving out reference to that obscure, functionally one-dimensional design known as “the hull”, which has obviously upset you, I’m not sure what your point is here. It is obvious that my remarks are solely directed at my own designs. I want others to know that with my designs, there is an “intention” behind each design feature, in this case fin placement. I want people to understand why my design works (or doesn’t work, for that matter). Some builders are satisfied with just replicating an existing surfboard design in a reduced proportion, hoping/claiming that it works. That’s not me. And just to be clear, I have never held that my designs are the only belly/body board designs that work, or that they are the “best” designs. I’ll leave that opinion to anyone who has ridden one of my boards.

clarification of your simplistic generalities of fin placement. read my post again for enlightenment.

i'm not the one upset.

everything works, its whether or not you like the way it works.

[rodndtube]

Play nicely, boys! Print doesn't always convey one's body language

On the Bonzer paipo front there are four of us that I know of that are riding similar boards and thus far each of has a different fin configuration that works for each of us (well, except for Bob Green, who hasn't found any that work for him or it is the Bonzer design or the issue are other design characteristics in his board that did not work to his expectations).

Dr. Robert tried a center fin but didn't like it. Jeff Quam tried the quad but didn't like it -- so he uses a center fin to get the ride he wants. Jeff's board is shorter than Robert's. My board is only an inch shorter than Jeff's, is a half inch narrower, a couple of inches narrower in the nose area, similiar width in the tail (12" from tip), but mine pulls in more at the pod while Jeff's remains wide (virtually parallel rails all the way through the board).

A friend sent me a 7 or 8 inch center fin insisting I would need one of that size. Turns out the 6-incher that came with the board was too much for me. A 5-1/4 was too much... I settled with a 4.5 inch FCS PC-5. Then I tweaked with the runners... as the board still felt too stiff with the standard issue Bonzer runners... I am in a much better place with 4 small Bonzer runners than the 2 small and 2 large runners combo; even substituting a pair of Knubsters forward was an improvement over using 2sm/2lg and the small 2x2 pivot fins I used in forward slots for a short while.

Back to the G4, I am still curious about the effect of reversing the forward and aft fins in Tomas's original arrangement he posted above. But... it is his path and he now has something working for him. Soulglider has also been down his path in the paipo experience and is in a happy place now.

It can be a real challenge to write without generalities at times, or writing by analogy. I often times make that mistake. For me what REALLY begs the most clarification in the paipo world discussions are the descriptions of flippers/swim fins! Well... in just about all discussions by boogies boarders, paipo riders, bodysurfers and others as to why one swim fin is good or bad. And people are simply not used to describing their swim fins in the same manner the quantify their boards in using multiple measurements (e.g., inches, weight, resistance).

</rant off>

[nomastomas]

sorry Rod...

SG…I see you’re still struggling to untwist those panties, and that you were up all night with the Thesaurus preparing your retort. I'll give you a B+ for vocabulary, but only a C- for grammar. Re-read your opening sentence. It makes absolutely no sense? And your finish, your "coup de grace"...OMG, "Everything works, its whether or not you like the way it works." Is that the best you can do? Really? I thought you were a little more astute in a surfcraft-design sort of way. I really expected better from you.

Its time to end this lively, but uninformative exchange of insults. I’m sure that others, like me, are already quite bored with it. So my advice to you is doing what I do with most of your pontifications…errr… posts…don’t read them.(sorry for being so simplistic) BTW, I suppose that that invitation to “stop by and have a beer” is off the table?

[rodndtube]

It would be much better for you boys to bury the hatchet, knock back a few beers (there are some good watering holes in San Diego and Ventura!) and share a few boards & fins for some surf rides.

Now I will go swallow a couple of ibuprofen...

[bgreen]

What can be enlightening is to try other's boards. I was recently in Wales and had a surf or two with Krusher. One surf, in admittedly ordinary waves, we swapped boards. We have different approaches to riding waves, Krusher being way more athletic than me and having a boogie board background. His board was finless and mine a twin fin. Krusher said my board was the first finned board he's enjoyed riding (though it didn't do spinners). Someone else might try my board and say it's a dog.

The bonzer - I rode two of Robert's boards, with fixed fins and found them way more maneuverable than my board. I rode both in small waves my bonzer wouldn't even get going in. I've had some fun surfs on my bonzer, but they have been a particular type of waves. More powerful and hollow walls being ideal. Rod's point is an interesting one - same basic design, but 4 guys have quite different takes on the fin configuration.

One day I'll find a wave reasonably close to shore where i can readily come in and fine tune the fins.

Sometimes my twin fins could be bigger but I enjoy the speed and semi in-control feeling. No doubt others wouldn't like this feel. You can see why I struggle with the bonzer configuration. One area where the bonzer shines is powering around/through whitewater - the finless/small fins just have nothing to hold onto.

Bob

[nomastomas]

"Sometimes my twin fins could be bigger but I enjoy the speed and semi in-control feeling."
Yes, with fins, riding on the edge means you're using just enough fin area for the conditions. Its hard to describe the feeling, but is as if your board will slide out at any moment, but doesn't. Instead you hold a high line, and go really fast. If I slip down a steep face, I know I need to increase fin area. I've also found that increasing fin cant helps with hold on steep faces.

"Back to the G4, I am still curious about the effect of reversing the forward and aft fins in Tomas's original arrangement he posted above."
Actually, I tried larger fins in the rear position before, albeit inadvertently. I was using a split-keel quad set on the G2. The split keel quad is literally a wedge-shaped keel fin split roughly down the chord of the fin. This leaves a deeper fin in the rear position. I wasn't getting the hold I wanted which led me to take a close look at the relationship of the outline to the fin position. I noticed that the larger/deeper rear fin was further from the wave face due to its position closer to the centerline, and the curve of the outline where it was located. I reversed the fins, and experienced an immediate improvement in hold. Two design iterations later, I still use the larger fin in the front, adjacent to the widepoint of the outline. There have been times when it "felt" like only the fins and about 12" of rail were in contact with the face. Can't prove it, but that's how it felt....

We should have some decent surf Monday courtesy of Hurricane Delores, so I should get a chance to use the larger 4.0 and 4.35 fins. BTW, I now have a "demo" 46" TBG4 Quad if anyone wants to give it a whirl...

[dr robert]

Rod, et all: just to throw in a little clarification about my boards, it's not that I don't like the center fin, as a matter of fact I ALWAYS use the center fin on my 4'6" 3 fin Bonzer…thats' the one with the traditional Bonzer runners.

However, I typically ride my 5 fin, 5" boards without the center fin simply because I remain entranced with the ability to drift laterally at high speeds , a technique which is functional both as a type of stalling maneuver, as well as one that seems to generate its own peculiar source of forward momentum when pressure is released and the need for down the line speed is required.

A trippy experience to be sure, but having said that, I do put in the center fin when things get heavy and I want/need to be able to carve and totally drive through without any drift at all.But, in reality , that is the exception and I use the 5 ft's as a " Bonzer quad" set up 90% of the time and love it to death.

At this stage, Malcolm has shaped about about 15 Bonzer paipo's for various and sundry…the majority 5 fin set ups, and with some curious exceptions (you and Bob!), the feedback has ranged from positively life altering to simply ecstatic.

I will agree with the typically cantankerous SG that "everyone likes something different", although some of those things that people like are a mystery to me…especially when ANYONE who's even remotely as cool, skilled, and knowledgeable as me ( did I mention omniscient?) has to acknowledge that (my) Bonzer paipo's are the absolute pinnacle of paipo form and function, and frankly will not now, or even ever, be matched or surpassed by any other paipo design, past, present, or future.

There, I hope that clears up things for all of you!

You're welcome