So I have this midlength I made a while back that shows a lot of potential, but has had a few issues. I initially placed the fin box too far forward for my liking, it’s a “hull” type board so I figured I would put the fin way up, didn’t like it, spun out. When faced with the decision to either route out a new box or chop off the tail a bit, I chose the latter. A 7’6" round-pin became a 7’2" diamond tail. The board performs much better now, but chopping off the tail left it pretty thick, not so foiled anymore. I’m thinking this is a perfect opportunity to grind 'er down a bit and make a flex tail mod. I figure it will add a little more control and I’ve always wanted to experiment with a flex tail - either glass panel or just tapered down real thin.
What I’m wondering is what sort of glassing schedule I need to make it structurally sound but still have a nice flex. Also, I am trying to decide between a straight glass panel or a more gradual taper. Any advice on design/construction would be greatly appreciated!
I like the semi-circle going into the thinned section. Good choice.
I was thinking I would maintain the same diamond shape of the original tail for the raised area. Maybe even make a deep raised diamond, bringing the tip close to the original tail tip, might create a bit of a V-flex effect.
Grinded off the glass on the tail and reshaped it today. At this point, it is about 1/4" thick around the outer edges. Think I will keep it as is or maybe grind a little bit more off. Next, the plan is to lay down 2x 6oz patch and wrap 2x 6oz over that.
[img_assist|nid=1067959|title=7'2" Flex tail mod grind|desc=|link=none|align=left|width=640|height=480]
not sure it is the right way to do it but whenI did mine I sanded the bottom with 80 grit to rough it up…then glassed about 8 layers onto the bottom to keep it stiff for when I remove the deck. Next I sanded to foam on the rail apex, routed a half moon shape on the deck, and removed a little section of glass from the deck, sanded down to bottom layers of glass and made a little ramp up to the deck. glass deck, and foil till it feels right…it took me along time to get it not too stiff and not to flexy cant remember how many layers all together, but it is foiled down so thickness varies through out the tail.
It seems like this is where a couple layers of the bamboo would really come in handy. Lay one layer as a finpatch for the box and stagger the others to create a ply.
it feels a little bit punchier out of bottom turns to me…when you start to come out of it it kinda shoots you out with speed like a slingshot. I did it on that board pictured because the tail rocker was really low.
I know it would be more polite to say nothing, but at the risk of once again being rude, I’ll jump in.
Astevens, I’ll be that actually, the board bogs coming off the bottom, is harder to catch waves on. ond is generally worse for the modification.
Surfboards move forward by resisting the force of moving water coming up the face of a wave. When you are paddling, and the wave first starts to propel you forward, it is because the waters movement has something to push against. The fastest water, and therefore most energy is at the top of the wave. By making your board limp in the tail, the area of the board that is in contact with the most powerful part of the wave is dead to the energy.
And secondly, contrary to the hype, a flexing object does not store energy. When force is applied, the object bends. When force is released, the object returns to its original position. The object would need to remain in the stressed position in order to store energy. An arrow in a bow works because the archer holds the string in tension. A sail in the wind won’t flutter and move the boat after the wind has stopped.
The board might turn quicker because the board is effectively shorter.
I know I come across as a dick sometimes, but would you rather that and make better boards?
By the way, I just did the exact opposite on an overly rockered tail. I added d-cell in order to stiffen the tail and lower the rocker.[img_assist|nid=1067649|title=Tail Rocker fix|desc=|link=none|align=left|width=826|height=469]
okay, I just gave this guy my feedback with a board I modified myself. the modification was much too stiff in the beginning. more grinding/foiling later resulted in a better board. doesn’t bog… does sink more in the tail when paddling but not when surfing. quite frankly, I don’t care how it paddles, more how it surfs. not limp in the tail…it is a very tense flex, not wishy washy, not too stiff…that was the hard part. I’m not on here to BS someone into something that doesn’t surf/feel good…not here to sell/promote anything either…just a backyarder like you and the majority here. If you don’t want to be perceived as a dick then don’t bash something that you have never tried before…next time I won’t share. I’m done.
spuddy,
good luck with your project, let me know how you like it
Don’t take it so hard! Nothing personal aimed at you.
I’m just trying to say you are heading down a wrong path.
I have tried it before, and I’m bashing the flex tail concept, not you.
The hardest part of an internet forum is to disagree with someone, and keep it positive and pleasant. But maybe that’s why so many really knowledgeable people don’t correct bad ideas, but let the other guy struggle.
That’s why I was concerned about coming off like a dick.
Here’s my last thought on it. We all agree that Coil makes some of the best boards available. Why do you think they wrap the tail in aramid fibers? Maybe because the tail shouldn’t flex? Why do you think they reduce the stiffening fibers toward the nose? Maybe to increase flex in that area?
But if you like having a board that bends behind the fins, enjoy! Maybe you are the first to discover something new that nobody thought of yet.
Once again Bill Thrailkill is right. We should really spend more time listening to the master builders. Hey Bill when is the next design round table seminar?
First Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another. The First Law of Thermodynamics (Conservation) states that energy is always conserved, it cannot be created or destroyed. In essence, energy can be converted from one form into another.
For argument’s sake, if you ignored the purported pros and cons of a flextail springing back and returning the energy it receives from being flexed, what basic benefit would you be left with?
Exactly. The perfect rocker, with mid to nose flex to absorb bump, and build additional rocker on a full rail turn. Stiff flex in the tail for control and speed. There’s your magic board.
