That's so cool and fascinating that you mocked this up! Stoked that this thread has created a really interesting discussion from a 2013 board!
I still find it crazy that they beveled a 28" wide performance shape, I can't wait to try it on a proper wave in good conditions and see how it goes!

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benjl said..
That's so cool and fascinating that you mocked this up! Stoked that this thread has created a really interesting discussion from a 2013 board!
I still find it crazy that they beveled a 28" wide performance shape, I can't wait to try it on a proper wave in good conditions and see how it goes!

I think the reason for that is that everyone knows these rails surf like magic. Even on this wide tail straight outline board I can run donuts
on a wave without leaving the centerline. For that to happen though, conditions needs to be pristine, as soon as the water has some texture
I have to outcast my self to the crappy lonely part of the break as I can't control the board from flying around.

Still waiting to see if any of the current board makers, still doing these rails, managed to find a good formula between performance and stability
for these rails on a sup.

One of these clean glassy days you'll get drunk on this board.

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burchas said..
Not sure about your comment that bevels has no effect on paddling speed

No, I was not speaking either of behavior at paddling speeds nor the ability to gain speed.

I was saying that my gut feeling was that for the same given speed, my gut feeling is that - for the same standing up paddling stability - rolling the board on the rail in turns will be harder on a wider beveled board than a narrow flat one for higher speeds.

And thus, for your example, maybe on pristine conditions, a narrower board will give you the same magic... without bouncing around when not glassy.

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colas said..

burchas said..
Not sure about your comment that bevels has no effect on paddling speed

No, I was not speaking either of behavior at paddling speeds nor the ability to gain speed.

I was referring to your comment from the other thread about beveled rails. I do see you point about about narrower board but we were
comparing same design, narrower VS beveled so to my point, the narrower one ended up with thicker voluminous rails so I suspect it's
kind of a wash in terms of which one will be easier to engage. Stability wise I'm going to struggle on both designs so I might as well stick
with the refined rails.

Back to the subject of the thread though, The question of what would be the right formula to end up with a stable design.
for beveled rails, sounds like HYPR Hawaii is onto something from reviews I've read.

Keeping the law rail on the same plane as the bottom stringer and adding a steeper under tuck to the rail with a harder edge from mid-section
through the tail. Maybe that's how you go about removing the wobble. The deep double concave can't hurt either, something like this:

Hey guys maybe a bit late to the party, I have a 11ft longboard SUP of roughly the same production date of the f one, it's got a pretty deep concave and bevels from the nose up to the side fins. Personal opinion - it adds manoeuvrability to what would otherwise be a pretty clunky board. It's totally stable but you definitely notice the wobble. My board has full rails, straight outline and a flat deck, so without the bevels would probably be hard to surf. I've had it out in overhead and it turns way better than what you would expect, similar to what others have said. The bevel is biggest at the front and you notice it when on the nose, can do drifting turns on the nose. Photo of the bevels below. Unfortunately I only have one photo of it in action which doesn't really do it justice but I've loaded it anyway.

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burchas said..
I suspect it's kind of a wash in terms of which one will be easier to engage.

My point is that it will depend on the speed. And this is why you may end up having some people preferring bevels, and other narrower boards: I suspect it will depend on the kind of waves they use their boards in.

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ECSurf said..
Hey guys maybe a bit late to the party, I have a 11ft longboard SUP of roughly the same production date of the f one.

Just in time, the party just started for me What are the board specs other than 11. At this length it would be inherently more stable
(although you seem like a big unit) but you mentioned you do feel the wobble. I'd appreciate more detail shots of the rail contours from
the other end of the board.

I longboard surfboards there is the Stewart Hydrohull and the Walden Magic bottom. I have surfed both of these and rail to rail feels easy but then you don't have to balance on these things while waiting out the back in chop. I think I am with Colas narrower board with flat or concave bottom as opposed to wide with bevels. Disclaimer I am not a great surfer.

Burchas, dims are 11' x 30" x 4.5". Swallow tail so really parallel, have tried to get photos of the rails, bevel flattens at the side fin. Rocker is pretty big for a longboard, like 7" middle to nose.I am 6'6 and 107kg so a fair bit of momentum to throw around but lighter riders still find that it turns easily. Rather than being tippy, it feels lively. I would suggest that might be due to the 30" width, length, full rails and it being quite a tame bevel. In terms of speed, this thing flies on a wave. Could maybe say that in this case the bevels work to give a bit of liveliness to a board with stability and glide.

ECS, the bottom shape, rail of your swallow tail 11' x 30" x 4.5" is looking very close to the Dabadie one that Colas did refer to.
Also, this board is a solid reference to this topic.

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ECSurf said..
Burchas, dims are 11' x 30" x 4.5". Swallow tail so really parallel, have tried to get photos of the rails, bevel flattens at the side fin. Rocker is pretty big for a longboard, like 7" middle to nose.I am 6'6 and 107kg so a fair bit of momentum to throw around but lighter riders still find that it turns easily. Rather than being tippy, it feels lively. I would suggest that might be due to the 30" width, length, full rails and it being quite a tame bevel. In terms of speed, this thing flies on a wave. Could maybe say that in this case the bevels work to give a bit of liveliness to a board with stability and glide.

Thanks for the pics ECS! Hard to see but I could not spot any hard edges on the rail on the picture looking from the fin up.
The full rail do help stability wise from my experience but trying to figure out how much a long hard edged rail would add-up to that equation

Looking to incorporate something similar into my next (big) board, like that is a 13x27 below, only with wider bevels and herder rails throughout.

Something along those line I guess.

Here you can see the bevels in action:

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burchas said..
Something along those line I guess.

I've been talking to Ian about getting a couple of boards. The 9' Nalu and a 12'6" Gun. The bottom shape freaks me out, especially the beveled rails. This thread explained a lot of that, but the hard rails all the way to the nose still freak me out... It's hard letting go of all those pronie shortboard prejudices...

I've had chine rails on my NZ Surfline prone mid-lengths for years. As I understand the science on those at least, it allows the rails to shed water instead of it wrapping around the rail making the board less sticky on the face. They therefore creates better rail release with a smoother ride, particularly on steeper, faster waves. Makes sense to have them on a SUP with the bulkier rails. Probably ideal for dropping into glassy Teahupo'o bombs but unnecessary for your average SUP surfer riding suburban slop.

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OkiWild said..

burchas said..
Something along those line I guess.

I've been talking to Ian about getting a couple of boards. The 9' Nalu and a 12'6" Gun. The bottom shape freaks me out, especially the beveled rails. This thread explained a lot of that, but the hard rails all the way to the nose still freak me out... It's hard letting go of all those pronie shortboard prejudices...

Analysis paralysis is a real thing when it comes to laying down 3K+ on unfamiliar boards with unfamiliar bottom. I can't speak about the
HYPR board as I just eyeballed it from videos and pics. I had my own shapes based on what I thought I would like.

Turned out great for the 13x27. Not so much for the 9x30 (in terms of stability that is). The hard edges throughout is a feature I'd like
to incorporate for my up coming 15 footer board. I Have a good idea on how it'll behave on downwind runs which is the main activity
for the board but not so sure about surfing the outer bar on a bigger days with that. I know they do some big waves guns that way but
that's above my pay grade. Not sure how it translates for you

The Hydro Hull (which is what HYPR is based on) is a well established shape and you can get tons of info about what it does.
The speed boost and early pick up is noticeable over boards with similar dimensions I rode.

different solution but to keep volume and get rails with bite a S deck like on the simsup may be an option - without the tippyness factor. I have one on a huge volume 8 4 simsup and it is noticeably different to a thicker rail, I love surfing that board!!! See an example in the pic below, basically the deck steps down towards the rail, pretty much all along the rail line. don't have any handy of my simsup which is an earlier model, but you can see from the shadows in this pic how the deck steps down to allow a finer rail with a relatively thick board...

One of the factors doing the bevelled rail is the fact that the inside edge of the bevel along concaves is puling in the nose line making the board more accurate to surf hollow wave faces with advantages like the stand up paddling as well as surfing glide on flats which is typical of the widest board.

I finally got to try the board in some proper overhead conditions yesterday. Ended up doing a 3hr surf! Bit of staying standing for that long in choppy, solid current waves but the board was pretty nice once on a decent wave! felt really smooth dropping in to a hollow face and also didn't need the paddle to help with turns etc, felt more instinctive and goes on rail naturally. def a board that can turn from the middle and needs to take off right in the pocket to get going!

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thegreatsup said..
...didn't need the paddle to help with turns etc, felt more instinctive and goes on rail naturally. def a board that can turn from the middle..

My sentiment exactly. Total upgrade playing backside.

Interesting thread Im a retired boat builder by trade , many.... 60 plus years of ,prone surf but now bit more sup so appriciate good hydrodynamic design and principals my two bobs worth would be Blane chambers got it right with his hull rippers amongst my quiver is one of his 10' 3" s and it does rip in big surf im on the sunshine coast and have supped the major cyclone swells we have had for the past 10 years and still fun in all the smaller stuff too. The vee running through the board without the concaves is the trick, transition rail to rail is effortless and the effectivly smaller bottom shape and so wetted area on the plane gives the speed out of turns and down the line coupled with a rail shape more akin to a "normal " surfboard dimension solid feel on the bottom turns when right up on the rail stability is not an issue with this design . I will be bereft if it ever dies in fact am considering either his new bevel designs or cnc and carbon construction of the original and I wouldnt tweek it at all .

Not keen on Bev rails. Seemed to be quite unstable for a 9'1" board and tracked quite badly, bottom turns not good either, hard to engage rail, but that might have been my ability, fin set up etc. at the time? Much more comfortable with stepped rails.

Not keen on Bev rails. Seemed to be quite unstable for a 9'1" board and tracked quite badly, bottom turns not good either, hard to engage rail, but that might have been my ability, fin set up etc. at the time? Much more comfortable with stepped rails.