Long storey short I have shaped a few surfboards and they have all worked as intended and shaped 1 surfboard for a mate for kiting and he likes it and it was a lot more aggressive in the sharpness of the rails and massive concave blah blah blah, it all went well:
Now I am starting to shape a mutant, surfboard thingy for kiting and want some ideas:
General idea:
Surfboard type construction (foam and glass with a really thick 15mm stringer)
Outline similar to a mako
Recessed deck like the axis surfboard kiteboards
Thruster at 1 end (5 fin setup)
Twin tip at the other
Pretty thinish with carbon fibre matting and Kevlar mat reinforcement
Paulownia timber veneer on the deck to get that old mixed with new flavour
Foot straps that have a lot of adjustment places
Here's where the advice comes in:
How much rocker do you think it will need?
How sharp should the rails at the rear/front be?
How much concave?
I have my ideas but want fresh ideas.
Some basic outline and recess deck photos below.
Oh size is 160 long x 42?ish wide and at the moment it's thick because I haven't started on the rocker yet. It'll take a while but the initial stage is thinking through the design.
Mako king is 165x45.
My gust says more width!
It seems the mako 150 is the most liked design.... when I rode the king it was super nice at carving but felt a little big.
So my gut says less length too.
Great project! RE: how much rocker / concave: can't define one without the other, they play together, and here is the answer I found to that question.
www.losethestraps.com/forum/viewtopic.php?f=0&t=942&sid=04b11055ec83ea726dcbd526ae6ed046
Select to expand quotetungsten said...
Great project! RE: how much rocker / concave: can't define one without the other, they play together, and here is the answer I found to that question.
www.losethestraps.com/forum/viewtopic.php?f=0&t=942&sid=04b11055ec83ea726dcbd526ae6ed046
Awesome link thanks for that! Good info for anyone wanting to build a board.
There's about 10mm of concave through the middle of the board and about 40mm of rocker.
I put a level through the water line and I think I've been kissed on the d**k by a fairy, it's a straight line as per the article you sighted!
That was not my design and I didn't even put together the theory but pure luck has given me the correct line! Thanks again
Hmmm. Can you tweak more Rocker out of it man? 40mm is pretty shallow over a 160cm board.
I could I guess. I would need to increase the concave! That rocker is gradual from the centre to about 2/3 up the board then it jumps a bit more severely in the last 1/3. The only thing I note is that because the board is asymmetric that when my weight is on the back foot the rocker will effectively be somewhere around 60-80mm.
Thoughts?
I'm not sold on the fact that you need a straight water line. Infact I think you want a curved one for the waves. Certainly you will have a more efficient board if it has the straight waterline. But I don't think it will be as good in waves. My board does not have a straight water line yet it is absolutely amaising .....
You might have missed the beginning of the linked article plummet:
"SHAPE - what makes a fast kite surf board
For the use with kites, most of the time we want fast kite surf boards. Unlike paddle surfers, who optimize their boards for the shape of the pocket of the wave they are made for, we want boards which go early, plane easily, for use with a smaller kite and in lighter winds. If you're lucky enough to live where it blows 24kn every day of the year, you can concentrate on other things in your board. Most of us are infested with light airs though."
tl;dr:
The straight water line makes for an effective and fast board. If you have enough wind / powerful waves, you can concentrate on other things in you board.
heres my alkita, a very addictive board in the correct conditions, it requires a bit more rear foot pressure to ride, when flattened out it spins on a sixpence, great grip through the turns and carves, the fin position and inward direction are very different but make sence, pretty technical to ride properly, my only gripe is spray and the howling noise the fins make when ridden flat out
Select to expand quotecauncy said...
heres my alkita, a very addictive board in the correct conditions, it requires a bit more rear foot pressure to ride, when flattened out it spins on a sixpence, great grip through the turns and carves, the fin position and inward direction are very different but make sence, pretty technical to ride properly, my only gripe is spray and the howling noise the fins make when ridden flat out
That looks very cool, never seen them before!
Any chance of some more pics? Rocker, underneath, etc...
Select to expand quotePlummet said...
I'm not sold on the fact that you need a straight water line. Infact I think you want a curved one for the waves. Certainly you will have a more efficient board if it has the straight waterline. But I don't think it will be as good in waves. My board does not have a straight water line yet it is absolutely amaising .....
I should have pointed out plummet that I don't ride in surf at all yet, just bay waves which are really just wind swell/chop
Select to expand quoteDaniel1973 said..
I could I guess. I would need to increase the concave! That rocker is gradual from the centre to about 2/3 up the board then it jumps a bit more severely in the last 1/3. The only thing I note is that because the board is asymmetric that when my weight is on the back foot the rocker will effectively be somewhere around 60-80mm.
Thoughts?
Others (OR Mako...) have successfully used a bit of flip in tip and tail, like the first and last 10% (15cm on the 150x34 Mako). look at the pic in the link, from the fin outwards rocker increases a fair bit. Works well, the board does not tend to pearl.
Ok fair enough. light rocker in the centre with increased tip rocker will make a sweet board for small chop/waves and light wind use.
Fair enough tungsten. I have alight wind board for the light airs. So my mutant doesn't need to be optimised for light wind. Its optimised for head to double head 20+knots!
All good points you both raise and it helps with the design components.
Tungsten - what do you mean by "the board doesn't pearl?" That's a term I haven't heard before.
Plummet - sorry for the lack of info at the start I should've mentioned there ain't any wave spots near me and I would't be confident enough for ground swell waves yet anyway. I'd surf 4foot at the most but not kite it yet!
you lucky bastard plummet. I can't even dream of that kind of conditions within 500km from where I live.
Select to expand quoteDaniel1973 said..
...- what do you mean by "the board doesn't pearl?" ...
To pearl is nose diving the board into the wave ending your ride with a face plant. Therefore you want a bit of nose rocker when it's choppy or you're in the waves.
Select to expand quotetungsten said..
The straight water line makes for an effective and fast board...
I actually meant to say efficient and fast. If it's efficient and fast, it's effective in light winds 
Select to expand quotecauncy said..
heres my alkita, a very addictive board in the correct conditions, it requires a bit more rear foot pressure to ride, when flattened out it spins on a sixpence, great grip through the turns and carves, the fin position and inward direction are very different but make sence, pretty technical to ride properly, my only gripe is spray and the howling noise the fins make when ridden flat out
O for awesome!
Select to expand quotetungsten said..
you lucky bastard plummet. I can't even dream of that kind of conditions within 500km from where I live.
Yes yes yes, very lucky indeed. Here's one of my local spots going off.
Select to expand quotePlummet said...tungsten said..
you lucky bastard plummet. I can't even dream of that kind of conditions within 500km from where I live.
Yes yes yes, very lucky indeed. Here's one of my local spots going off.
All of a sudden it becomes clear why you think I need more rocker!
I'd probably try waist high waves at max at the moment and even then I'd want to be a bit in front of the pocket and fully powered!
That sort of s**t is reserved for experienced kiters (or crazy bastards)
hehehe. yep i keep forgetting that my reality is different to many others.
I'm getting to a point now where i'm not absolutely ****ting myself in those conditions. I don't ride conditions like that all the time. But it is also not unusual.
Anyway back to the board build. It sounds like you are on target then with your rocker and water line. I still think a tad wider would have been better. That is the general trend for boards these days. More width and less length.
The mako king i think is 165x44 but the 150 is 150x40... so your 160x42 may very will work.
If we calculate the surface area of an ellipse (the mako shape is essentially an ellipse)
Surface area = Pi x A X B
www.thoughtco.com/surface-area-and-volume-2312247
The area of 160x 42 is slightly smaller than 150x45 for example.
What does this tell us? increasing the width 3cm is equivalent to 10cm is additional length as far as surface area is concerned.
I never actually thought of the surface area to be honest. When making surfboards I always just work with volume estimates for the boards. I really need to start thinking surface areas for future boards. This one will have to continue as planned and see how she goes.
In this regard, a board is nothing more than a sort of wing which produces lift. Volume produces static lift and is important if you have to overcome a take off phase with little power to do so (surfer). kite boards are powered by the kite, thus the dynamic lift (which is proportional to the surface are) is the important one, not the volume. More so as the dynamic lift force for a given surface is proportional to the square of speed through the water.
Interesting points Tungsten.
Board building involves many tradeoffs. Its quite cool playing with different factors to achieve your desired ride.
More length = more doing spinning tricks rotating mass is very important! The smaller the better.
more width = better light wind performance. But too much width means you have to stomp heavy on the board to hold the rail. Wide boards get over powered quickly.
More Rocker = smoother riding = more power hungry. Less rocker harsh in chop better in light wind.
Stiffer = better light wind performance = harsher in chop. good load and pop, harsh landings..... flexible boards are smoooth But can be power hungry and absorb load and power.
Retangular board outline (typical TT) = better upwind, better load and pop, worse through chop and waves. Typically smaller and more manuvourable. Ellispse shape (like mako) better in chop/waves, worse at load and pop, more power hungry. typically larger in size. Ellipse shapes can hold more power for the same size
Ahhhh.
What is certain is that there is no one board to rule them all. Just boards made with a mix of the above variables that suit different riding styles better.
Plummet, Where are you kiting in that video? I understand if you dont want your spot to be known.
I have to agree wider the better just look at Tomo's boards with the no nose (Firewire Vanguard). I have not surfed one yet but have spoken to guys who ride them and say they are fun and fast under the right feet.
Board shaping is a fine art and is slowly getting lost to CNC. A lot of younger guys are seeing the benifits of shaping there own.
Daniel1973 Cool Thread dude.
