Quad Concave Body Board Study

What works and what doesn't. Share design ideas, references and contacts for paipo board builders.
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bgreen
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Re: Quad Concave Body Board Study

#21

Unread post by bgreen »

If a tip sticks out 160mm and the distance between tips is 700mm that makes the board 380 mm wide (about 15"). Is that right?
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Re: Quad Concave Body Board Study

#22

Unread post by PhillyViking »

following are the closest boards I could find to your wings. Mostly the wide back. Except that instead of having distinct dorsal fins the entire board has some delta shape characteristics.
'
K. The paipo guys at Queens Beach in front of Kapiolani Park (near the Honolulu Zoo), Larry Godard Interview, mypaipoboards.org
paipo_guys.jpg
Paul Lindbergh Interview, mypaipoboards.org:
PL-wood-paipos.jpg
PL-wood-paipos.jpg (9.95 KiB) Viewed 1049 times

My closest breaks are in New Jersey USA. They get a bit nip in the winter so I go south as much as possible. Be careful in the cold. I lost a lot of hearing in one ear to "surfer's ear". Of course those rock concerts didn't help.

I did get to surf in Norway a couple years ago so have had some exposure to the North Sea:
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Re: Quad Concave Body Board Study

#23

Unread post by CHRISPI »

bb5.jpg
My boards are the same as a wood Paipo but with soft buoyancy draped on shaped in a teardrop form. I could use plywood but it is too heavy and lacks the bouncy and strength of Airx foam. The photos I sent deform the true shape of the board.
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Re: Quad Concave Body Board Study

#24

Unread post by PhillyViking »

are your wings added on or part of the core airex core? Do you have any pics or dimensions of the core before adding the soft shell? Which of the airex foams do you use? Its an interesting candidate to address some of my pursuits:

* stringerless boards with just the right amount of flex and damping with stress distributed evenly
* More durable boards especially for travel

The Body Board world starts with soft foam and tries to control flex as an afterthought with rods and mesh close to the outer layer. I like your approach that starts with flex control.

Atlantasurfer on this blog made boards with Home Depot plywood for flex control and adhered soft foam on top for buoyancy and shape. viewtopic.php?f=4&t=681&hilit=black+betty It worked amazingly well but is heavy. He got flex like an alaia.
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Re: Quad Concave Body Board Study

#25

Unread post by CHRISPI »

The wings are part of the core with added layers of cloth after shaping. Very easy to press form rocker and fin angle I put in about 2 degrees in my fin pitch. My supplier is East coast fibreglass supplies I mostly use Airex PVC C70, also 3D core material but is very resin rich and a bit heavy but exceptionally strong, I want to try Aramed honey comb core but it looks difficult to lay up I have also tried extruded polystyrene but can’t get the correct density in thin sheets very light and cheap but fragile in the low density form. I am using 2 sheets of 5mm x 1.09m x 1.02 about £25.00 a sheet , can make a second board out of the off cuts .so £ 50.00 for 2 cores .
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Re: Quad Concave Body Board Study

#26

Unread post by CHRISPI »

You can change twist and bend flex by adding layers of cloth down the core spine. I feel flex in a board is desirable
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Re: Quad Concave Body Board Study

#27

Unread post by PhillyViking »

I am trying to build flex into my board as well. I have done a lot of mat riding where you really work shape shifting. You actually turn by twisting the mat (nudge the rail upward on the opposite side of the turn ). The floppier the mat, the more suction to take you down the wave during take off... etc. My goal is to make a board that has the best of mat and board behaviors. At 67 I am feeling the need for a leash (NA on a mat) and need some harder turning ability for certain conditions than i can perform on a mat. But I want the mat experience hence my interest in flexible, finless boards.

This next one will be a skinned HD EPS core. I am changing my plan for this board a bit as I think about composite fundamentals. I was going to build all my tensile strength in the bottom epoxy/ fabric layer and just adhere cork directly to the deck to address compression only. I was influenced by Tom Wegener who only builds strength on the bottom of his newer cork boards.

I have now realized that Tom Wegener has the constraint of only working with wood and cork in conjunction with an EPS core. He asserts that wood on the deck is prone to cracking compared to the bottom because of the tighter radius of bending. But the consequence is he needs more wood on the bottom than if he allocated less wood overall top and bottom or better yet in a multi layer sandwich .. that is the lesson of plywood. So I will put some epoxy/fabric between the eps core and cork deck. I only need enough on the deck to address break/bend forces .. the cork will handle compression. In theory I will need less glass by making a sandwich. On conventional builds there is typically more glass on top then bottom. But that's to handle compression from our bodies, not for tensile strength

This will also address Rodndtube's comments that I need to be concerned with downward as well as upward forces applied to the board, e.g. a big wave lips that hammer down from above. In this way I can do a layer at a time .. first the bottom and then decide 4 or 8 oz on top once I can evaluate the flex of the just the bottom. Its temping to use some unidirectional strips for fore-aft stiffness in particular but I just do not have a way of knowing how much I need and it should be the first layer adhered to the core.

I wonder if given Wegener's constraints, that he might do better to make a thin internal structure with 2+ smaller thicknesses of wood veneer closer together in a sandwich with foam, cork or other less dense material. That way he would avoid the tighter radius encountered if he placed the wood on the deck. It seems Ski, Wakeboard, Skateboards builders are doing more with composite materials and sandwiches than we are in the surf world.

I am now am using a higher density EPS sourced from Greenlight (NJ, USA) that they call Cfoam. Its somewhere around 2 rather than 1 pound density. It is noticeably stiffer and is less likely to tear during shaping.

I am trying to understand composite fundamentals. Lets say I wanted a board that was two inches thick to get the desired buoyancy and shape. Which is stronger: a thin inner sandwich structure to handle all the flex surrounded by less structural material or to spread the stiffer materials out in the entire thickness of the board. I think the latter. Am I correct? If i was using EPS I might want to get the thickness sliced into e,g, 3 thin sheets and glass in between them. In my case I would use 1/4" cork on the top and bottom of that for compression concerns. So maybe three sheets of 1/2" EPS sandwiched with fiberglass and thin (1/4") cork on the outside.

Another case for internal structures. We often overly glass travel boards in particular to protect against compression dings. In doing so we trade off flex we might have wanted. If we separate compression vs tensile strength concerns we can use skin materials like cork or soft foam to absorb compression and right size the amount of flex control in the internal structure. I am not saying that a paipo might not get broken in half in transit or in the surf but it is far more likely to get dinged. Has anyone actually broken a paipo (sponges excluded) in half?

Thanks for the material sources.
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Re: Quad Concave Body Board Study

#28

Unread post by CHRISPI »

Layered and veneered structures get stronger with concaves , it’s so easy to press form layered shapes .there are so many types of skin layering to try out .With polyethylene , cork ,etc it’s easy to change a shape or add to after testing
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Re: Quad Concave Body Board Study

#29

Unread post by PhillyViking »

What adhesive do you use to adhere PE etc. to the internal sandwich structure? The BB builders use heat welding for plastic to plastic but its harder to find an adhesive for plastic to epoxy/fiberglass that is effective but not nasty. Epoxy gets a mixed review at best. Barge contact cement seems to be a candidate .. the newer formulation might be safer?

I am interested in the detailed steps of your pressing process. I have been using vacuum bags for some of my epoxy projects but do not like that I end up creating a lot of waste from the throw away peel ply and bleeder cloth. I am trying to find ways of being eco sensitive.

It strikes me that some of the high density PVC foams (airex or divinycell) could be heated up then thermo pressed with or without an exact form. Maybe as simple as using a heat gun then mechanically pressing before it cools. The epoxy / fabric could then be hand layed up with detailed shape added to the outer material by hand (no vacuum). I like using cork where you use PE etc. but the approach is the same. I will try using cork in the internal core structure in the future but in the mean time I just use it on the outer 1/4-1/2" skin.

I can see doing an internal core sandwich structure with High Density Foam / Fiberglass as you describe, surrounded by thicker sheets of EPS and then cork on the skin. In that schedule, the cork can be adhered to the EPS with PU adhesive and the EPS with the structural sandwich using epoxy. Detail shape could be realized in the outer EPS and/or cork. The internal structure could be very very basic in shape and could be used in a variety of builds once the process is established.

Alternately, since we need some float anyway maybe just use HD EPS for the internal structure sandwich instead of even higher density PVC. The HD EPS might need to be thicker than then the PVC foam? Thats where the PVC might shine: you can go thinner. But as I said above, do we need to go thinner if we want to add float anyway. I am not clear on the science of how foam thickness would impact strength if the same three layers of glass was used otherwise (glass-1 - foam - glass-2 - foam - glass-3) . My understanding is that thicker foam layers makes it stronger. Am I correct?

Are you exposing your HD foam/Fiberglass structure on the bottom of the boards? If so, maybe I should not be referring to it as being internal. However, its still as if its internal in my thinking but maybe there is a better term. May I should just call it the (thinner) structural sandwich in contrast to outer layers used for buoyancy and shape.

Do you make an exact form to press against or use other approaches? I see people bending material over a 2x4s etc. Harry Akisada , see https://mypaipoboards.org/interviews/La ... dard.shtml has a great example of pressed veneers with complex channels albeit with wood. I see clever approaches to bend wood against objects without an exact form but have a harder time visualizing doing the same with HD foam with pre-cured epoxy/fiberglass in process. Of course vacuum against an exact form is the sure way to go but making an exact form for a one off is a lot of work.

If you are using a fiberglass / foam layer on the bottom then the concaves would add stregth. But, there would be less strength added if the concaves were added to a thick soft foam bottom.
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Re: Quad Concave Body Board Study

#30

Unread post by CHRISPI »

I used to use contact glue but it is difficult to lay up large pieces, after some testing I now stick the pe with laminating epoxy it has the same adhesion as contact glue but gives time to move the pe around before it sets, with contact glue if you make a mistake its bad news. For the core lay the centre first normally with one layer of 6 oz cloth, with extra strips or patches over areas that need strength .lay batons underneath to set rocker concaves etc use waits to set the shapes. After the shape has set I clean the rails to size finish with 45 deg bevel and lay 6 oz cloth top and bottom. Best way to understand how strong core structures are is to lay up samples and test them by twisting, bending, pulling and crushing them.
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Re: Quad Concave Body Board Study

#31

Unread post by PhillyViking »

Your shaping against batons makes sense especially since you are using two thin foam sheets to make the initial sandwich. If I have it right then the initial lay up is foam bottom, 6 oz glass middle, and foam top. Weights are used on top to push the thin flexible sandwich against the batons. The key is that the epoxy/FG is in between the two foam layers so is not going to adhere to the weights. Likewise, peel ply etc is not required.

I imagine that compared to bending wood , bending thin foam sheets does not take much pressure. This would seem much easier to execute then what ever Harry Akisada had to do to bend wood to a complex shape. Am I right that I should expect the thin foam to bend more easily than even wood veneer? I assume that once that initial center core sandwich is completed, the outside FG layers can be layed up without additional use of the batons. One layer of 6oz in the core is sufficient to hold shape until the outer FG layers are added for final strength in a subsequent step.

I really like your approach. I would just leave the outer FB layer on the bottom exposed and then add EPS on top for float and then 1/4" cork on the top of the EPS for comfort and compression concerns. Oh, I just realized the problem would be that the any concaves pressed to the center core would be reflected on the top of the initial sandwich core. That means any layers added to the top of the initial sandwich will not lay flat. How do you deal with that?

Solutions:

1.) Do you weight your PE deck to the core and then shape the reflected contours on the top of the PE deck. Its hard to imagine getting the PE to drawl into the contours of the core if not flat just using weights. A vacuum would work well for that and could be used without a lot peel ply since the there still is not epoxy on the outside in that step.

2.) Level off the top surface of the core using a small amount of expanding foam that could be sanded down to a flat surface or even use it to adhere the EPS other outer material in one leveling/adhere step.

3.) Leave the internal core surfaces flat and in my case add a layer of cork on the bottom that would accommodate shaping concaves or other complex features .. 1/4"-1/2" of cork would handle anything I might want to do on the bottom that is not flat. This approach would lend itself to changes to be made after testing in the water. Cork could be easily added, removed, shaped. Titebond and sand paper are the only items needed for change. In my case, cork on the bottom would add some relative weight but on the other hand I would not need to use innegra on the bottom for compression concerns. Cork does a great job absorbing compression but is not abrasion resistant like innegra for an outer layer, especially for the bottom. So I could take a hit on the cork bottom but not run it up to the sand on a beach break.

Thanks for your response. I was on a similar track of thinking but you are helping me clarify my own plans.
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Re: Quad Concave Body Board Study

#32

Unread post by krusher74 »

PhillyViking wrote: Wed Jul 29, 2020 3:27 pm I have been looking at the trend in Body Boards to use quad concaves. The shallower inner set is for turning and taking a high line and the outer set to move water out the back fast and to further help with turning when sunk. Most of the BB makers have at least one in their line up. Its interesting to read how they relate design variations to riding objectives. Its good food for thought if nothing else.
All the companys that have one are because they all come out of the same NMD factory in indo. Nick mezrick did the quad as a cnc cut and now seems to have licenced it to every company he makes boards for. Its been a good seller as the bodyboard markey has had lettle new for 10/20 years.

The bodyboard companies as a whole dont seem to be much for inovation, I think alot of this is that there isnt a shaping pricess when you can try ideas.

thats why i initally moved to paipos as it gave me a chance to try out designs that the surboard industry has been using for 40 years and i have never seen transfered to a bodyboard.

My fave personal board pretty much has the opposite of what you are doing. central single concave with outer V, and i cant come up with a design that betters it. My design is basicaly a wegner TUNA hull atached to a bodyboard template.
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Re: Quad Concave Body Board Study

#33

Unread post by PhillyViking »

I am glad you (krusher74) jumped on to this thread.  I rode a  paipo board this summer and fall that I built using the rail and bottom design derived from my Wegener Tuna.  I was influenced by your posts.  I agree that is a great approach .. it turned well and I stuck some steep faces.  At 48 x 19 X 1.25", it's longer, narrower and thinner than yours.    I do feel the need for some more float and planing surface area for take offs and slow sections hence my next build.  I will increase the width to somewhere in the 20-21 inch range and the thickness to just over 2 inches.  It would be safer for me to stick with the Wegener design , I know it works, but have been seduced by the prospects that the quad concave might work for me even better.  The only way to know is to make one and try it. I can always circle back to a Wegener design if I do not like it.

At this point I would be happy for the new finless build to work up to overhead + in US east coast beach break conditions but I would love to have a single board that could do that and work in heavier - longer period surf I encounter in Costa Rica.   I built a Bonzer paipo for CR which is in its own class in turning / sticking ability compared to my previous paipo boards and surf mats but it has too much fin for milder conditions.  My observation is that fins do the job when needed but they also drag when you do not need them.  Hence my interest in finless designs that can turn hard and not drag.

I have not had a chance to try my Wegener design in CR as my trips were canceled due to Covid.  However its hard for me to imagine that it can so as well as the Bonzer.  My favorite CR break requires a hard bottom turn on a heavy wave.  On the other hand, your reports give me cause to think that its possible with the Wegner design. Likewise,  videos I have seen of BBs with quad concave design show some hard turning finless. However,  I am not ready to leave the Bonzer at home, but perhaps?

I would love to hear more from you about length.  You seem to have made yours more like a BB at 44 inches.  I notice that one of the up-sides of BB length prone boards is that they can be readily pivoted fore-aft.  Boards with my length and longer are harder to push down a wave when a quick move is required.  Likewise,  the less out front when making big air drops or going over the falls, the better.     Larry Goodard talks about needing more length for speed when it gets big and need speed.  What are your thoughts?

I will keep my noses thin to that they can be pushed down.   I recently made a board that was huge with a thick nose.  I thought that would work in small beach break but ended up feeling I was always fighting the board to get it to pivot.  In those moments I saw my buddy who was riding a fiberglassed BB shape with twin fins easily pivot forward in the same context.

I am trying to learn the up and down side of BBs and various paipo designs for different conditions.  It seems that those that have migrated from BBs to Paipo boards have done so to move to a stiffer board.  Of course, design variations are readily available as well.  The refrain seems to be that stiff boards go faster but at the cost of the agility of flex.  As a mat rider I find that flex or maybe I should say shape shifting lets you to go real fast but is a challenge when a big hard turn is warranted.  The BB buying guides seem to say get more flex for turning and stiffness for speed.  Likewise, they promote curvier profiles for turning and parallel for speed.   What are your thoughts on flex?
  
I intentionally sought some flex in my current wegener design because I like the feel and believe it helps to naturally fit into waves and to a point, turn as a finless craft.   The feel part of that comes from my mat riding background.  In a perfect world I would have the shape shifting feel and adaptability of a mat but turn more decisively like my Bonzer.  You seem to be saying your board does it all?  Are there conditions where you might want something different?

What are your newest thoughts on nose design.  I am also a Harry Goddard fan.  I got to meet him in Hi.   I am looking at nose designs at https://mypaipoboards.org/interviews/La ... 2-Nose.jpg.   I am thinking some where in the 75% of width at 6" curve for the nose as seen on that sheet.  Thats actually somewhat  close to my current build.  By reference to LG's designs it looks like your board is more optimized for bigger waves but I think you said it works in smaller conditions.    Whats your current thinking on your nose design?
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Re: Quad Concave Body Board Study

#34

Unread post by krusher74 »

Comming from 20 years of bodyboards into paipos i knew what i liked in bodyboards. In nearly 50 years of bodyboards I think they have definitively shown that the optinum length covers a very short range. Being 5.10 a 42" would be typical for me,and thats what i have found to be optimum. 41" feels like a toothpick, 43" feels like a boat.
So my paipo template is taken from my fav 42" bodyboard (adding the pointed nose instead of a blunt nose is all that makes my paipo 43")
The outline template I found to bethe best point of curvy enough to turn well and straight enough for good speed. I also found with the template that the one main position i ride this board n is also it sweet spot for leaning forward to go , leaning back to stall and the best point to pivot a turn from. This minimizes having to move around on the board.
I then added as you know the wegner hull and a rail that was half wegner half bodyboard and in the front somthing that had to happen to transfer the angled rail into the hull nose in the from 1/3 of the board.
And hey presto it worked. in the last 5years plus every design experiment i have made to better that design has just make it worse.
Its goes in irish slab barrels of death, long point breaks, 1ft grovvels. (i did try to make a bigger version of it to make grovel surfs a bit easier, but that also failed, see thread i have on that board)
So basically this board is better than my ability, i need to surf better/harder to finds its flaw if it has any. its will bottom turn as hard as I ever want no matter the size of the wave.

as far as stiffness, i just find stiffer is faster and find d=no drawbacks from the stiffness. I have never found the bodyboard thing of needing sofer board for colder water, i just find them slower with no gains.

I feel i an truely lucky that i have lucked out on making a board that so good for me, but it did take 5 years of trying to make it better to realize how good it was.
The only experiment i have next it to try to add a few liters of volume to it without losing performance, just for slightly easier wave catching ability in soft or small condictions.
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Re: Quad Concave Body Board Study

#35

Unread post by PhillyViking »

Usher, You are fortunate to be at peace with your stable design. Maybe I will get there on my path. I do see the benefit of keeping the board short enough to trim and turn simply by leaning fore and aft from one position. However, I can't help thinking the blunt nose of a standard BB pushes water hence the idea of extending the nose for cleaner water entry. The trick is to add nose for cleaner water entry without losing the benefit of ready pivot.

The sizing you mention for your BBl's baseline is close to the standard charts I see for commercial products. I am 6" but with a proportionately long torso so I was thinking 42.5, maybe 43 would be my equivalent baseline. Then I would add nose as you did. However, I was thinking of adding 4-5" more nose to the baseline. Most BB templates have a blunt nose of around 11.5-12.5". My baseline would have a 12" blunt nose (e.g. 43" baseline length) before designing the extended nose. I have been thinking I need the 4-5" extension in order to drawl out the nose to any significance if I am to retain the original 12" nose (4-5" back from the new nose design).

You only added 1". To get the template of the nose I see in your picswould seem your baseline would either have a narrow nose to begin with or you shaved some off in your design to get the gradual nose transition. Was your baseline nose narrow to begin with or did you take some material away to get the extended nose? Or what?

Can you separate how much of the design that is working for you came from it being more stiff than a foamy and how much comes from the extended nose entering the water more cleanly?

Regarding your consideration of adding some float: I have become sensitive to the behavior that with too much float you lose that pivot magic, can't sink rails and duck diving becomes exhausting. Of course that's if you go to the extreme like I recently did with a 52x23x3" board.

Your endorsement of the single concave approach causes me to pause on my quad concave infatuation. The single is working on my 48x19x1" version. Maybe another inch + of width and 1" thickness is all I need.
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Re: Quad Concave Body Board Study

#36

Unread post by krusher74 »

I think the nose has way less effect on the board than you think it does, I feel i could make the next copy of my board with the same blunt nose as the bodyboard the template was taken off and it would not ride noticeable differently. That part of the board is hardly in the water when riding. My bodyboard had standard width nose when i made the template for the paipo pointed at only a 1" longer it the arc/curve to that point probably cut through an inch either side of the bodyboard nose shape. ( as you said i shave a little off) 4/5" extra nose i feel will also stretch out your front arm too a less advantageous angle at the elbow for turning.
I have an old bodyboard that i love as a summer cruiser in small waves (and have used it in good waves many times) it has an oldskool 13.5" nose and never causes any problems, it in fact give much more frontal planing area to get very far forward to get extra speed in weak waves. Drop knee specific bodyboards have the smallest noses and they are horrible to ride prone compared to and standard dimensions prone board.

"Can you separate how much of the design that is working for you came from it being stiffer than a foamy and how much comes from the extended nose entering the water more cleanly?"

I think the nose has very little to do with it. and the bit that does is my nose having slight belly which help to cathc wave from 0mph before planing speed.
I think the stiffness, concave and thinner rail are the main aspects that make it work.

As an experiment i had a custome bodyboard made to as closely as possible replicate my paipo design, and as a bodyboard it does not seem to gain anything from those design features, and is certianly no better than the original bodyboard the paipo template was made from. The bodyboard copy is lacking the thinner rail, overall rocker, front belly as these can not be made because of the want a bodyboard is constructed.

I also think at 19" your board is narrow this with not help in turning. my paipo and all my bodyboards are over 21" wide.

one of my friend also bodyboards and he is 6.2 and has used my board and well very well on it. he has also rode 42" bodyboard all his life as he is lightweight.

Im sure the quad concave has merits but how long, how deep and at what angle could be a 20+ board design project to get right.

in 25years plus of bodyboarding i have heard or read so little and about r&d on them, I know the pro have their own models and get to like a certian template, length, thickness and core. But I have never seen anything about a design process on the quad channel so have no idea if it the best of 20 prototypes or the just did one it rode ok and they just went with it, the pro arnt riding the quads in competition that i know of. they are riding designs we have had for atleast 10 years+.

its a shame we cant have get togehters are try each other boards as that speaks 100,000 words.
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Re: Quad Concave Body Board Study

#37

Unread post by GeoffreyLevens »

Surfmats have totally blunt/square noses and in several years of riding one I never had a single issue w/ it pushing water.

On length/width: Dale Solomonson once quoted Greenough to me about how one of his favorite things about mats was that the "throttle, brakes, are steering were all in the same place, directly under you."
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Re: Quad Concave Body Board Study

#38

Unread post by PhillyViking »

thanks for the thoughtful comments.

krusher74, I need to build a "safer" design along the more known lines of yours, Wegener, my narrower previous iteration of the same (but more volume), etc. and another that might be 1 of 20 experimenting with quad concaves. Making two boards is not a problem but getting surf time is. It would be great to swap boards .. I recently took the time to make a real floaty board for small beach break and pretty much dismissed it immediately upon trial. Actually, getting over to your area (Wales, Ireland) is on our list once Covid allows, Maybe we can meet some day.

For this iteration, I will definitely go wider, thicker and shorter than my previous iteration. Something more like BB dims. That would mean 43-44 length, 21 width, and 2+ thickness. There are reasons to go longer but this one is about trying shorter. Not sure if I will do the safer design or 1 of 20 quad experiment first.

There seems to be a case for sticking to a conventional BB nose. If there is no difference between a blunt vs thinned out nose at planing speed then putting the extra width (planing surface area) of a blunt nose back in might help at slow speed. Likewise, as a novice builder, it would be much easier to build a conventional BB nose. However, rolled displacement nose might not work as well on a wide as narrow nose? I wonder whether that if at some point it creates more resistance to push to the side as to just get up and plane.

While neither a BB or Paipo this vid makes the case for a blunt nose and moving water at the nose under rather than to the side. https://www.youtube.com/watch?v=8BDZwESf--M

I will keep the rails thin so I can sink them down to engage a turn. That seems essential to make the overall finless rail, chine, concave design work. Otherwise fins would be needed.

Excuse me if you already described your overall rocker but what is it? I am thinking just enough in the nose and otherwise flat or 3/8" in the tail at most. Whats your thinking? Foamy boards flex rocker a bit. We give that up when we stiffen up.

GeoffreyLevens, Point taken on mat noses etc.. I ride mats as well. However, a mat can shape shift whereas a rigid board can not, Many of my best rides ever were on a mat. I am only focused on paipo boards because some of the conditions I ride warrant a leash and my skill level precludes making some of the critical big turns I must make. If I could get to the skill level of GG I would be at peace only riding mats. I still ride mats but I match my ride to conditions.
GeoffreyLevens
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Re: Quad Concave Body Board Study

#39

Unread post by GeoffreyLevens »

PhillyViking wrote: Thu Oct 15, 2020 8:44 am However, a mat can shape shift whereas a rigid board can not, Many of my best rides ever were on a mat
Yes, that's. That is why you must shaped some rocker into a more or less rigid paipo and a mat does not need any. Mats you "shape during the ride" as needed. Paipo you have to decide on a compromise amount, a pre-set, always a compromise... And of course there are some solid advantages to a hard board, things you do not get with a squishy mat.
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Re: Quad Concave Body Board Study

#40

Unread post by PhillyViking »

It just occurred to me that in addition to mats having even more blunt noses than a BB that they are also short (compared to a 48" + paipo) like a BB, The mat's squishyiness is a great feature when you do a big air drop to a flat landing. I put 1/4" of cork on my paipo boards but its not the same.
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