MyPaipoBoards Forums

Lots of interesting design elements going on there, will try to come have a go on it this winter!

Do you have any video of the boards in action ? They look great and the design is intriging, I am very curious to see them in the surf.

On my to do list....

I've had the opportunity to ride the FX a couple of times now, and I have received feedback from a customer who owns a G2, G3 and FX, as well as plywood paipos. Our consensus opinion is that the FX performs as well as any finless prone board. And as a a finless shape, it takes different lines than a finned prone board, requiring more of a go-with-the-flow approach. I had high hopes that the channels would significantly improve the hold, but that has not been the case. In fact, the channels are not worth the effort to shape and glass them, both being a PITA. As you would expect, the board is fast when it finds its line, and loose and eager to spin (if you enjoy that sort of thing). Not eager to take and hold a highline for more than the time it takes to turn back down the face. While faster than a soft prone board, it is definitely slower than my finned boards. Bottom-line: not my cup of tea....

My experience with the FX shape dovetails quite nicely with my recent fin experiments with the G5. I have been using less fin area by using the rear boxes for the largest fin and either a smaller front fin or no front fin. What I have found is that placing the larger fin in the rear enhances turn response, especially in smaller waves. But, hold in critical parts of the wave varies directly with the amount of fin area. During the recent Fabio swell, I ran a twin set up with 4.6" fins in the rear position. Seemed to be plenty enough fin area. On the drop-in on 5ft waves, I found that on landing there was a bit of drift down the face, maybe a foot or so, before rail and fin engaged fully. That drift feels like a slight wash-out or stall. With a quad set up, the board will fully engage immediately and almost leap forward on landing. I really enjoy that feeling and the lack of that feeling is what turns me off to finless. But the standard large fin front, small fin rear quad set up ends up being more carve-y than pivot-y, turn-wise.

Next steps will be (1) sell the FX to someone who appreciates the finless gig more than I, and (2) add a 3.7" front fin to the 4.6" rear fin in an attempt to strike a happy medium between hold and turn response.

Thanks for the update.

I agree that a finless board draws different lines (and different finless boards draw different lines).

Whether the FX performs as well as any finless board is a big call. I've gone down a few different board design paths, one of these paths started with one of Larry Goddard's designs (I'm trying to recall the original model I replicated) . Now I am on number 7. I've ridden them all finless and finned, and have mostly left the small fins in (less than 5"). The exception is the current board, which I've only ridden finless. It rides as deeply in the tube as I'm capable of and I've not been tempted to try fins as yet. I have a trip coming up to South Africa, so that should be a good test.

I 've never tried channels, my latest board has a deep double concave. An interesting development will be what direction John Galera goes. He rides his finless boards in large Hawaiian surf. He has been given a twin fin which he is going to ride. I'll follow his experiences with interest.

Bob

Nomas, I find the same thing to be true in using skegs: quickness with precision and speed coming out of turns. Much of this observed and experienced with a couple of other guys riding everything from Xylem wood (with and without fins), bodyboards, surf mats and finned paipos. It is a different way of riding, finned and finless, and everybody has there preferences and I can certainly admire both.

Interesting to hear feedback on the finless. (the FX looks to have a lot of curve in the template which would slow it up?)


The only experience I had was with the one fin-able board I had, when I took the fins out it felt much faster to me.

But the perception of speed can be an odd thing. I think as humans we feel a change in speed more than a constant. So think an acceleration from fins on a turn maybe make finned boards feel faster. But the finless could have a faster average

Does anyone know the actual science of fin drag? I read the faster a fin goes the more drag it creates. But do they actually create drive forwards or just aid direction change? And that finless just goes faster and faster as the wave goes faster.

The lack of scientific rigor plagues all surfcraft design theory. And, yes, we are all left with mostly subjective data on which we hang our design theories. Subjectively, I can say that surfing finned is to me more enjoyable than surfing finless, regardless of the size of the surfcraft in question. I can also say that, from experience, there are sections I can make finned, that I wouldn't make finless. But whether that is because I'm going faster or because I don't slide down the face, I couldn't tell you.

But it's not all about reducing drag. Drag, in general, reduces speed. The relationship is inverse; more drag = less speed. Fins do add drag to the total "form drag" of any surf craft. Total absence of drag leads to maximum speed, but at the cost of control. Drag figures heavily in control, whether it be increasing the drag on the rail of a finless shape to execute a change of direction, or using the drag of control surfaces, i.e. fins, to allow the surfcraft to reach and maintain position in the most powerful part of the wave. Turning up a wave face (finless or finned) slows my speed due the the drag I must apply to initiate the turn and due to the force of gravity acting against my intended uphill path. But such a maneuver sets me up for an increase in speed when I turn back down the face, stop applying drag, and stop fighting gravity.

And, just to muddle things a bit, those legs and feet trailing behind the prone rider also produce drag, and at times are used for control surfaces.

For me it all boils down to the lines you want to draw. The line I prefer is to land mid-face on the drop, regardless of the size or steepness of the wave, and accelerate immediately, without drift or sliding down the face. I then use that speed to execute my next maneuver, which could be could be a lip bash or a cuttie, or simply holding a highline, depending on what the wave has to offer. I have found that a properly finned board is the best way for me to achieve that line. If, like me, you can't draw that line on a finless board but want to, we should talk. If you can draw that line finless, then congratulations, you have little use for a finned prone board.

One naturally thinks that fins add drag, or slows the board. Thinking back to the series of studies and the book by Lindsay Lord, Naval architecture of planing hulls, he found that a 2:1 ratio (length to width) was the ideal shape for speed (coincidentally, this is generally the bodyboard ratio). If three large regular fins (e.g., 5 to 8 inches) were added to this 42 x 21 inch shape there would be considerable drag and one could conclude that natural speed is slowed down. However, if the fins were smaller (e.g., 2 to 5 inches) and foiled, the speed equation could change. For example, in "Surfboard fin science," at http://finsciences.com/surfboard-fin-science/, Doug writes:

• "Fins do two things, and only two things. In terms of science, fins create two forces, and two forces only. Surfboard fins create lift, and fins create drag. That’s it. In general, you want more lift per unit of drag–just like with airplane wings, boat keels, propellers, helicopter blades, and car spoilers. The laws of physics aren’t suspended for surfboard fins.
  
  When we’re talking about lift, we’re mostly talking about sideways (horizontal) force–it either helps you turn or resist turning by giving you something to push off of. (Of course I say mostly because fin splay (tips set wider than the fin bases) or in the case of our fins, winglets, give some component of lift vertically).
  
  In general, a fin moving faster generates more lift (side force) than a slower-moving fin. The design takeaway is that IF your fin is capable of producing good lift, THEN you can make it smaller, and THEN it will go faster, and THEN will produce even more lift–and THEN go even faster still. In surfing, we feel “more drive” as efficient fins generate lift (sucking force) with more speed. This lift or sucking force is why efficient sailboats like America’s Cup catamarans can sail toward the wind at several times the speed of the wind. Wings–and surfboards, are effectively sucked forward by the force of lift, and increasingly so with speed. In the case of airplanes, the sucking force of lift puts gets them airborne."

Then there are the holding and turning for speed aspects that Nomas mentions above. Nonetheless, we all enjoy riding different boards for different reasons and the enjoyment is at the heart of learning.

So with a twin fins or quad the outer fins being single foil like plane wing can give lift. But central fins being twin foil would just create drag?

Tried these Thomas https://vimeo.com/24847687 (rastas "spiral" talk sounds like a loads of hippy bullshit to me. lol)

It's complicated

OK, I'll chime in. I have the sister FX. I think Thomas built his because I was talking to him about doing a finless board. Some background I'm a old guy who had to give up stand up because of loss of function after two knee replacements. I sold everything and was about to shoot myself when I discovered piapos. Over the last few years I've owned and ridden a Xylem, a couple of other wood boards from a couple of makers, and two or three home builds. I loved them and had a ball learning each board's characteristics in the environment where I surf. I learned to deal with the lack of buoyancy of the wood boards. I'm a big guy and most piapo guys weren't sure how to deal with that. The one thing I missed was the control with a finned board. I stumbled on to Thomas and I knew his glasser which meant to he's probably all right. I also found we were theoretically on the same page in most things. I ended up buying a G2 with lots of options. That took me to the G4, then a displacement hull board done by Thomas. I wanted him to do it because he understands what and why he does what he does and the design theory, which held true even with the hull board which may have appeared a bit out of his design wheel house. Turns out it's a beautiful board. I've become attached to the foam fiberglass boards and wanted a finless one, so who better than Thomas to shape it? It works well. The one thing I've discovered is the finned boards, particularly the G5 I've just ridden has more speed. I also noticed the FX has a great deal of turbulence at the back. I think the four finned boards, with a well designed bottom, direct the water flow more efficiently, hence more speed. Also, the water exiting the channels on the FX may even make it worse. I'm curious about a G5 without fins. But, back to the FX, over all it works as I expected and is a great fun for a finless board. Also, props to Thomas. He's pretty smart and great craftsman.

Daryl D wrote:OK, I'll chime in. I have the sister FX. I think Thomas built his because I was talking to him about doing a finless board. Some background I'm a old guy who had to give up stand up because of loss of function after two knee replacements. I sold everything and was about to shoot myself when I discovered piapos. Over the last few years I've owned and ridden a Xylem, a couple of other wood boards from a couple of makers, and two or three home builds. I loved them and had a ball learning each board's characteristics in the environment where I surf. I learned to deal with the lack of buoyancy of the wood boards. I'm a big guy and most piapo guys weren't sure how to deal with that. The one thing I missed was the control with a finned board. I stumbled on to Thomas and I knew his glasser which meant to he's probably all right. I also found we were theoretically on the same page in most things. I ended up buying a G2 with lots of options. That took me to the G4, then a displacement hull board done by Thomas. I wanted him to do it because he understands what and why he does what he does and the design theory, which held true even with the hull board which may have appeared a bit out of his design wheel house. Turns out it's a beautiful board. I've become attached to the foam fiberglass boards and wanted a finless one, so who better than Thomas to shape it? It works well. The one thing I've discovered is the finned boards, particularly the G5 I've just ridden has more speed. I also noticed the FX has a great deal of turbulence at the back. I think the four finned boards, with a well designed bottom, direct the water flow more efficiently, hence more speed. Also, the water exiting the channels on the FX may even make it worse. I'm curious about a G5 without fins. But, back to the FX, over all it works as I expected and is a great fun for a finless board. Also, props to Thomas. He's pretty smart and great craftsman.

How does the "great deal of turbulence" feel? tail of the board feels rough and bouncy, chattery?

Feel it on the legs where the board ends. Having spent the last almost 50 years of life in the racing industry, I, in my mind called it turbulence and attributed it to the fast moving water under the board, accelerated by the channels hitting a low pressure area behind the board creating a swirling turbulence which in race cars becomes drag. Haven't really noticed it in my other boards and frankly haven't spent a whole lot of time thinking about it, it is what it is, and most importantly, it's still fun. Do it again, not likely, but if I do, it'll be a more conventional with two channels and attention paid to separating the water exiting under the board at the tail from the tail. This wasn't noticeable on my wood boards because they are much thinner. The design has merit with room for improvement. I enjoy a finless ride at times and that's the reason for the board. I, like Thomas, was hoping for a bit more stick, but it's finless! You might ask how I know the finned is faster. I was surfing with my old guy buddy, he on his G5, me on finless. He could pretty much run me down any time. I think for two basic reasons, he could hold the board in the stronger part of the wave, and bottom design including fins. Just my thoughts.

Daryl D wrote:Feel it on the legs where the board ends. Having spent the last almost 50 years of life in the racing industry, I, in my mind called it turbulence and attributed it to the fast moving water under the board, accelerated by the channels hitting a low pressure area behind the board creating a swirling turbulence which in race cars becomes drag. Haven't really noticed it in my other boards and frankly haven't spent a whole lot of time thinking about it, it is what it is, and most importantly, it's still fun. Do it again, not likely, but if I do, it'll be a more conventional with two channels and attention paid to separating the water exiting under the board at the tail from the tail. This wasn't noticeable on my wood boards because they are much thinner. The design has merit with room for improvement. I enjoy a finless ride at times and that's the reason for the board. I, like Thomas, was hoping for a bit more stick, but it's finless! You might ask how I know the finned is faster. I was surfing with my old guy buddy, he on his G5, me on finless. He could pretty much run me down any time. I think for two basic reasons, he could hold the board in the stronger part of the wave, and bottom design including fins. Just my thoughts.

Thanks for the explanation. Thomas CAD modeled my original finless handshaped board which has been beaten to death , the machine copy of it has turned out to surf just as well as the original it a simple shape which on the next board I was going to add more channels to for extra grip for better direction changed, but now i feel that may be a bad idea but you never know till you try I guess I'm happy for anybody to use the cut file if they want to try finless. I am sure thought hat thomas's finless design is sound and am hoping to try it if i get to california before its gone!

if you like cars have you been watching our festival of speed? https://www.youtube.com/watch?v=67IvQwZZLVU

I would not say this design is without merit. It is decent and has really cool rail design. Frankly, design is a learning platform for the next build. I think Thomas did a great job for a one off. If you get to CA and want to give the board a ride, even though I'm in Oregon, I'll try to arrange it.

Daryl,

It's good to hear BBs kept you interested in life and surfing.

Daryl D wrote:Feel it on the legs where the board ends. Having spent the last almost 50 years of life in the racing industry, I, in my mind called it turbulence and attributed it to the fast moving water under the board, accelerated by the channels hitting a low pressure area behind the board creating a swirling turbulence which in race cars becomes drag. Haven't really noticed it in my other boards and frankly haven't spent a whole lot of time thinking about it, it is what it is, and most importantly, it's still fun. Do it again, not likely, but if I do, it'll be a more conventional with two channels and attention paid to separating the water exiting under the board at the tail from the tail. This wasn't noticeable on my wood boards because they are much thinner. The design has merit with room for improvement. I enjoy a finless ride at times and that's the reason for the board. I, like Thomas, was hoping for a bit more stick, but it's finless! You might ask how I know the finned is faster. I was surfing with my old guy buddy, he on his G5, me on finless. He could pretty much run me down any time. I think for two basic reasons, he could hold the board in the stronger part of the wave, and bottom design including fins. Just my thoughts.

I don't believe it is as simple as finned is faster. The fastest board that I've ever ridden is the fastest whether I ride it with fins or finless. All my boards have removable fins so I usually start riding a board finless, get to know it and then try it with fins to see what difference there is. My fastest board is flat bottomed and flies from the point of getting into a wave and goes faster the more power there is. It handles steep drops and faces but it isn't a great tube rider.
My current board isn't as fast, but has more stability in the tube. The tail view of my current board is below. I've only ever ridden it finless:
I've surfed with Krusher a couple of times. We swapped boards one day in junk surf. I think we both agreed that we rode really different boards.

The "waggle" is what I call it, and I experienced it the most when I would duck dive. Very pronounced and unsettling, almost enough to pull the board from my grip. Very odd; no explanation for it. Never felt it when riding, though.

Sorry Keith, I've already sold the FX to BellyRider, but intend to add some FCS plugs on the rear corners before giving it to him. Maybe I'll get a chance to ride it finned. Daryl would be your best shot.

I really enjoy working with customers like Daryl. It's really fun to do "what-if-we-did-something-like-this?" exercises, especially with someone who has a lot of experience riding prone. And, we pretty much talk the same language regarding design and prone boards, so that's a big plus.

Drag is not an issue if it ultimately leads to greater speed or more responsiveness. Your fins have to earned their keep. The "lift" produced by asymmetrically-foiled fins is horizontal, pulling the rail slightly forward and into the wave face. I use asym-foiled fins in both front and rear quad positions, with slightly less toe-in on the rears than the front, when both fins are relatively close to the rail. The fins mimic a twin-fin set-up in this position. The front fins clean-up the flow around the rear fins, and a four-fin set-up seems to be more efficient (more hold,with less drag) than two larger twin-fins. Sometimes I set the rear fins half-way between rail and centerline, using symmetrically foiled fins. This has the effect of a center fin and of smoothing-out rail to rail transitions. You get less drift and more predictability in turns. A nice quality in OH waves, where control trumps freedom from drag. I tell my riders that if the board feels like you're dragging an anchor, you have too much fin area for the wave conditions. On the other hand, if you feel like the tail is slipping, even a couple of inches or so, you don't have enough fin area. Every rider needs to find what fin combinations works for their body weight and the wave conditions they are surfing.

I fixed the FX....
Rides more like the G5 now, just not as fast.