The other classic to reduce drag is to ensure your side fins are not to thick.
If you want more drag to slow a rocker line up,,,, well thicker fins will do this.
The fin technolohgy and materials over recent years has increased water flow efficency and lift and flex. reducing drag
A fully normal curved outside foil with a curved inside inner foil are slick through the water, and reduce all the dragg associated with running a thruster setup.
Good shaper should be able to make you a few dragon teeth.
Then theres all the plastic stuff........m3 general go... again thats for 105kg rider.
So im assuming that could feel a bit big for lighter punter.?
Hi reflex,
yes, i agree, it's impossible to really know without sailing a built version. i guess it's just ideas at this stage.
Hi King,
brilliant stuff. you've clarified a lot for me there. the fore fin setup is a bit of an unknown for me so getting the principles was very helpfull. on my current 2+1 setup i'm pretty sure the boxes were future fins. i'm running 4.5in 80/20 foil x5 xrated glass fins. they feel good but i can feel more drag than the single fin setup. i'd like to try a setup with less toe and see what that does and even try symetrical foils. woul most likely need to go to mini tuttle fins for that.
so i took your advice and moved the centre box forward a bit and the front fins back a bit.
stance width on the design is 450mm, that's similar to my freestyle board. do you think further apart would be better again?
i have a 7mm V through the flat area to release the rails. that spirals at the tail. i'm thinking that's a lot of V but i bumped it up as the board is so wide. i might reduce that back a bit to 5mm
i briefly spoke with a mate tonight who has a lot of experience shaping. he asked me to ditch my rocker dim method i used and give him balance point dims. he thought a 7mm kick from the flat was ok for a wave board but wanted to know overall rocker.
i did a quick calc and it appears i don't have enough nose rocker and possibly tail rocker. from balance point i get about 23mm tail and 170mm nose. i'll push the nose to 200mm and tail to 30mm.
Hi Ken,
one of the coolum crew has a delta thruster. he smokes it up in the surf. the delta boys have shaped a lot of pro boards over the years i believe. here is a photo i took of said coolum crew at currumbin back beach.
If you have an idea for a board, then you should build it. That's the the only real way to learn anything. The worst thing that can happen is you get a starting point for the next project.
^ yes, all true,
but i still need to pay for it. and not being a "dragon slayer" it's hard to fully justify a pure wave board. usually these thing take 2-3 boards to get right when the experiments begin. plus i'd like to build 2 boards. 1st one a proto i can hack the tail up to try different winger arrangements. 2nd one the final outcome.
whether it's a 105lt fish or a 100lt freestyle wave is a hard call to make right now.
i'm kind of fixating on the winger idea a little and would like to persue that. have been drawing up lots of versions of tails. might yet go for a double winger tail. i can get the ofo width down to 41cm and still keep plenty of meat between the straps....
Gesty, my thruster has the assyemtrically foiled fins that KOTP described above, and I bought a new set a couple of years ago, which have not seen any action on the water yet, so are in perfect nick, if you wnat to have a look at them.
The inside foil is about 1/4 of the outside foil, as I recall. I still need a new centre fin for it though, as he only sent me the outside fins, which was daft.
After all this discussion, I am definitely getting that board out again for some use this summer, weven if I have to drive to find the wind.
It was a blast using small boards again in Maui, and I want more of it.
That's a great shot you posted from Currumbin. I can see the big bottom turn coming.
Hi Ken,
sounds like an 80/20 foil.
i found this gem from Keith Teboul
1· The board feels so loose but at the same time you have an absolute feeling of control, I had the sensation it could hold a much wider tail without loosing control and maintaining most of its turning ability, do you think the quad could be the answer for a really good ultra light wind or big guy wave board? Are you going to shape anything bigger than the 85?
This I think is where the quad really excels, big volume wave boards and boards for bigger guys. In general with a Quad or twin you want to ride about 5 lts more than you would a single fin because than you have more range with the board and you don’t loose any performance because it is a quad and you have plenty of turn.
I shape a lot of 85 and 90 to 95 l. quads. I am making a 110 l. quad for Fred Haywood at the moment.
2· On the other hand, I had the sensation that the board wants the base a little bit more to the tail than usual (at least that was my sensation sailing in Pozo Izquierdo) is that true? Any fine tuning tips you want to give to the quad users?
In general the quad is a little more back foot than a twin or single. If you want more drive front foot you can separate the fins a little bit to get more drive and move your mast track further forward.
3· I couldn’t believe the turning ability of the board, the day I used the 75l, there were some little waves in Pozo Izquierdo (onshore), in this conditions, usually, after the off the lip you just go down with not too much control and any traction, but with the quad I kept having total grip and traction on the second part of the turn too, I had the sensation that with a bigger wave I could be doing roundhouse cutbacks with that board, it’s the first time that on a windsurf board I have the sensations and possibilities than on a surfboard, did you have the same sensations there at Hookipa? Did you ever expect reaching such a level of performance or at the beginning the quad surpassed your expectations?
For sure this is why we ride quads, the carving sensation through out the whole turn and the fact that the board helps you finish turns. Having that feeling of carving with power and speed with such ease I believe is one of the feelings we really look for in windsurfing.
Yep, 80/20 foil is what rings a bell. I was going to say that, but I wasn't sure enough to risk sounding like a twat if it was crap.
Can't wait to get it on the water and see how my memory of it compares with current reality and to my recent memories of how the new boards went. I found their upwind performance good when totally powered up, but not overwhelming in normally powered conditions.
It's only about 75L though, so might have to wait until summer.
All the hyberbolic talk about this design or that is overshadowed by the fact that everything works in good wind and everything feels like crap in no wind.
Greetings everyone, 80/20 foils are a great concept on thrusters as they allow a thicker foil on one side with great lift, yet remain thin enough to give the fin some flex.
I think they would also be a good to be used on quads for the smaller front fins.
Your board outline looks great Gestalt I just wondered do you really need the fliers? would the tiny area you have taken out with them make that much difference?
cheers finmeister,
you pose a very important question there and one that i have been contemplating for a few days now and don't have the answer to.
i guess i've been looking at the latest innovations in surfing. those guys have really been pushing the limits over the last few years and i've taken some inspiration from that. i can't find much theory on wingers around so it's a bit of a stab in the dark.
i did do some figure and tried different tail shapes sketches. the single winger seems a little pointless. a double winger outline though does reduce the tail area by about 15%. but raises a lot of questions like where to start the wingers etc. i can't get curves and a swallow tail to achieve that yet. whether it works or is even detectable on a working board i don't know yet.
my current fish with a 45 wide tail tends to skip out in anything around shoulder high surf. it's a single fin so no doubt fore fins would fix that to a larger degree but i figure why not take it further. my current lightwind tri fin rounded pin board i tried at 38cm, 42cm and 45cm tail widths as prototypes. 38 was to narrow, and didn't have good volume distribution through the length. 42 was great for carves etc but i wanted more get up and go so it went to 45cm after a few outline tweaks. it's a do all board so the width was ok with tri fins but for a dedicated wave board it's to wide.
from my sketches the winger/swallow tail allows plenty of width between the straps to keep the thing planing in lighter winds (same width as my current board)but lets me get the width ofo down to around 41cm and has all of the benefits that swallow tails have at the rail.
by reducing the tail i'm hoping the board bottom turns better allowing more commitment and speed which hopefully means more vertical top turns. i'm also hoping the wingers help the rail break free of the water when wanted and also give it a bit more speed for normal sailing.
of course i may be barking up the wrong tree. 
i'm not a wavesailor that's for sure but my current fish needs replacing so the opportunity is there. it may be that a conventional shape works also.
Hi Gestalt
I've had a bit of experience making wide tailed boards for light days and underpowered waves for cross onshore slop.
When I made 45 cm wide single fin tails they popped out of the water sometimes mid turn I put this down to the fin being to far from the rail.
I have tried to find a pic of a plan shape I used about 7 years ago but only found this partial diagram the tail is 45cm wide and yes it is square at the tail just like the pic.
As soon as I used this tail plan shape as a twin fin it never popped out, it turned tighter and was one of my favourite boards for crappy conditions.
As it was a twin fin on the turn one fin was always close to the rail and fully submerged holding the tail in the water.
I found that on a weak wave it was quite important to have all that tail width as it kept the board driving/floating on the mid part of the turn(when the board was banked over onto one side) where normal narrow tail boards would start to sink and then loose speed. Quite a few guys tried this board and commented how well it turned and kept turning.
For such a wide tail it has sh1t loads of vee like from memory about 12 to 15mm each side!
It had no problems with speed or control being a twin fin and it doesn't have the drag of toed in thruster fins.
the planning of a board is half the fun, the other half is seeing if it works or not.
Yeah, that probably sounded a bit more harsh than I intended.
You are right, tools for jobs, or I wouldn't have liked the thruster so much over the years.
No substitute for horsepower though.
I fitted a second rear footstrap in front of the main one for easier turning on a wave and for security in marginal planing conditions, when there was not enough power to have my back foot right back. Having your feet closer together makes any board turn so much quicker.
It's an old trick, but a good 'un, worth considering.
that's great riders,
i appreciate your experience here.
seems the wingers might need to go then. there's a few people not in favour.
on your sketch did you also make the tail 200 wide? or at least wider than 180 as well as remove the wingers?
with your wider boards what rocker were you going with along the centreline? i keep thinking 10mm
then 20 something at the rail? that'll give a deep V
I quickly just did that by eye, I'd say they tail would now be about 200mm or 210mm I also pulled the back f/s plugs to about 200mm from the tail in the drawing.
The rockers were curvy along the CL I dont have any flat spots to to take a tail rocker measurement from. I still cant work out how the reviewing magazines can find a flat spot which would vary on all boards and then work out comparable rockers on all boards? It would give a rough guide but not an accurate one. Oops went off on a tangent then.
good call on the vee mr Riders
when it comes to tail flip - i like 11mm measured from 300mm off the tail.
finishes off turns very nicely. Assuming everything else is set up nicely.
Maybe a twinny needs a little less..
cheers guys, i understand how much experinece you are both bringing to the table.
i don't get the board measure idea either. it's impossible to know whether you've got the ballance point and whether your straight edge is horizontal or not. even with a rocker with flat in it it still doesn't really tell you what curve was used prior to the flat being added. how the mags do it is beyond me.
the other thing both you guys are touching on is what curve was used to design the rocker? that's a hard one and i don't think measurable by eye or hand.
i've used elipse curves so far.
i measured the ofo rocker on the profile i uploaded and it's 13mm. back of my mind i've been thinking that i'll eventually reduce the rocker along the centreline as i don't want to much drag and wave boards for qld tend to like a little less rocker.
thoughts with rails would be a hard rail at the tail going to medium tuck through the strap area and onto very soft in front of the mast. my current board has that and i like it. board tracks well. the difference with this board is i was going to go for a thinnner rail throughout. i guess if i go to thin though the board won't release properly and loose a bit of momentum.
aparently big wave boards should be pink also. that's what my daughter tells me. 
New 100lt Nude Twin. 64cm wide
Haven't ridden it yet due no wind.
Looks sweet though.
Also pic next to my 100lt evo.
that's a great looking board roberto.
you and hoops must be very pleased. graphics look brilliant as well!
hoops - is that a tint in the finish coat?
good news for me is that my board will be getting built once the shaper gets back from his annual 2 month trek to jeri. there will be a few minor changes like a little more width and a reduced flat length plus a slightly higher rail point and taking on some of the comments in this thread, but all in all pretty much the same board i uploaded.
will also do a 100lt freewave i've been working on.
That is porn.
Seriously.................PORN !!!!!!!!!!!!!
Gesty, on flyers, I had a few twinny surfboards with them years ago, and they were always a really weak point, prone to dings and always needing repairing.
Diffeeerent amterials and technology on a sailboard, I know, but even so, probably more trouble than they are worth.
They look cool though.
Gestalt, the pigment goes in when the board is glassed and it has a clear filler coat.
I made a board with flyers in the tail last year. It didn't loosen it up as much as I thought it would. It did look good though. That board has been sailed pretty hard over last Summer and the flyers definately didn't cause any weak spots.
I'm keen to see your board when it is built.
cheers hoop,
will definitely post photos once complete. i'm expecting about a 6 month program so it may take a while.
hey ken,
i'm not so worried about winger strength. all of my boards are bomb proof with timber veneered outers and carbon kevlar at the important areas. makes them a little heavier but worth it for me.
Yes, it's totally different build technology to a glass surfboard.
I still like the pretty blue one.
I can see something like that in my future.
Just getting back into sailing this year, production stuff was the way to go, but down the track a bit, it could be the go.
^ well there are a lot of very good board shapers in OZ, some of them have even designed the production boards people use.
reality is though, custom board builders also make production boards. you can walk in and buy one off the shelf. usually they are good because they will suit local conditions specifically. you can also get one of their designs they know to work and have it tweaked to suit you more specifically or your graphics added, which is really what a custom board is. i think the general public think they new design everytime. of course you can get new designs if you want.
sometimes, like my big board there are no other options on the market. none of the manufacturers build a board like my big board. the fact that i helped design it and designed the graphics made it even sweeter for me. it was a process i really enjoyed. so i'm doing it again.
having a sailing mate that builds boards has been a blessing for me. i've sailed everything from the wierd and wacky to the conventional, tried and tested and untested prototypes. it's been a blast!
