"Reverse" parabolic stringers

…any of you thought about it?

Makes sense?

I was thinking that is not so hot like the parabolic ones or even the middle stringers.

 

It can be usefull if you want a flex tail.

But I believe that it won’t reduce twist like regurlar parabolic stringers do.

I think I’ve seen a board with stringers like that on swaylocks one day.

Are you talking about coming from the rail toward  the center and out the rail near the tail? It'd be tougher to shape, but you'd have more stringer in the center after shaping than a typical perimeter stringer. Of course, you'd have no stringer at the nose or tail unless you added a center stringer. I think you could get a similar effect with the stringers offset on either side of center, like some of the boards Slater's been riding in recent years.

http://www.youtube.com/watch?feature=player_embedded&v=uUauB_35hOg

like this ?

…hello Knowaloha, no like Surfthis say; however, I think that that tail do works better than the reverse stringers

Uwl in France do it with flexcel2 blanks from teccel (if I remember well).

I’d say Hans is correct - twist-city

 

As with the Outer-Island shape in the video, the tail missing the centre stringer would flex more. Potentially a weak point too - the stiff bit next to the soft bit = break point. That would be why Mitchell extends the carbon lap past the stringer/rail exit.

 

Also be something like triple stringers where the timber exits the rails…a bee-hatch to shape. 

 

There were old G&S boards which used the “reverse parabolic” glue-up in the 60’s. Somebody might find the old adverts - they look cool.

 

JD

 

Need some pictures to get the initial question clear!

Heres a few stringer setups i have been playing with, the triple is a bit stiff but will be strong as, normal center stringer and two bamboo side ones, the double stringer one has stringers through the fin lines which made sense to me in terms of strength and flex, freeing the tail up like the outer island idea… will add carbon to it to add more strength like speedneedle says to avoid the weak point, as its just two bamboo stringers.

If i get reverbs question it would look something like the crude pic i drew up of the inversed parabolic , would be a good option i think but a bitch to shape and glue up… ha might have to give it a go…


**Parabolic geometry** may refer to:

let’s not let science get in the way of surfboarding.

 

Like this?

Just saw this one on Craigslist. From ACE

…hello Lemat, I never heard about flexcel2; I use flexcel and its not reversed.

Hello Speedneedle, so you say that those guys do the reverse stringers then do a wide carbon rail lap?

Here s a board from your land:

those are called “butterfly” stringers …more for looks than for anything else. 

 

I can see the logic behind the stringers ending up from the tail, creating a hinge point in flex designs.  Mitchell Rae, on his website, discusses how he scoops out the tail, adds 'ribs', and basically custom engineers each board to the rider and power of waves.  The 'V-Flex' model incorporates the double wedged stringers which exit at the rails in the tail.  On some boards he's shaping a deep concave between the stringers... the scooped tail, ribs and carbon reinforcements are added in the glassing process.

http://www.outerislandsurfboards.com/articles.html

 

I didn't know that was what Rennie called 'em.

I had a look at Some Outer Island pics - The “V” stringers don’t necessarily include a carbon reinforcement lap, though there’s definately carbon involved in the ones with the EVA tail section.

 

Maybe the strength issue I suggested isnot such a big deal. The carbon sections in the pic seem to stop in line with the stringer/rail exit - I’d surmise that this is in order to carry the flex progressively from that stiffer exit point. I’d say otherwise the flex would be spongy rather than twangy. 

 

524382_441359822546020_681725065_n by JD_Shape, on Flickr

 

 

I also found some old G&S pics - not the ones I remember. These look like they’re intended to invoke the lines of their original logo more than anything functional. G&S_five by JD_Shape, on Flickr

G&S_four by JD_Shape, on Flickr

G&S_one by JD_Shape, on Flickr

G&S_three by JD_Shape, on Flickr

G&S_two by JD_Shape, on Flickr

These were named the “Hot Curl” model.

images by JD_Shape, on Flickr

I always liked yer basic wedge glue-up…close at the tip , with a 3" spread at the tail (on a 4" pod)…very functional , and good insurance against any potential board snaps from heavy waves…