Gestalt said...



now working on mk2 freestlye, wider tail still, 45cm at 30 cm from tail and thinner throughout. i've learnt that the width between the straps of the hull is very important. the duck tail now has a chamfer as tail thickness is less.

can't wait to sail that.

looking at starboard. they impress me with inovation, they are now designing boards with wingers that are still wide between the straps and up front with little rocker. all of my experiences so far suggests that this is the way to go. mr love's boards have similar tails also.

im looking forward to seeing the mk2 are the graphics a decal if it is it must have cost a fortune
you know Gestalt if i stuck some of those wings on my board like martin loves but i wouldnt make the nose fatter, id do it like that angolo board, the thickest divinicell ive got is 8mm so that will give me 16mm extra width, do you think that will make any difference(cos those wings wouldnt be any wider than 10mm a side) take in mind the extra weight of the resin

Keef , I don't think adding the wingers would have any advantage to your board. The idea of the wingers was to have a really wide, short high aspect planning surface, stepping down quickly to a reduced surface area in the tail, My flat is from 300 to 600 ( 1.5 mm tail rocker from 300-0)and the rocker is quite high under the mast track.
Adding the wingers to your board with it,s very flat drawn out rocker line would only increase the wetted surface ( unless you created the winger by taking material off) and do nothing other than increase drag (although may improve early planning a bit)
My board is a very different concept with the wingers being an intregal part of the overall design so just adding them to a board with a very different rocker probably would not work.
My 2c
Seeya Martin

hi keef,

yeah i don't think adding wingers would improve the speed of your board. it would definately improve planing threshold but at 16mm i doubt you would notice it. 3-5cm overall and you would notice it. but then you would need to also look at footstrap position etc. now cutting wingers into the board would be worth a shot for improving top end speed. but as stated prviousy the extra thickness in the board you are using may be just to much of an issue to begin with.

what was it you didn't like about the original board?

my comments on extra width are aimed at building thin boards, where you still require a certain volume. you either put it in the thickness or make the board wider. this thread was talking about how to build a narrow board and still get extra volume into the mix without upsetting the ballance. (enter the term virtual volume)

my vote is for wider over thickness. problem with wider is that you create more drag. hence the stepped tails, wingers, cutouts, channels etc. other boards use tail kick but that requires more skill to sail as you need to set the board at the right apparent angle.

taking an existing thick board and making it wider still is only really improving the light wind ability of the board.

the graphics i did were laser cut vynil sticker decals with sprayed base colour and template sprayed black spots. yes the vynil stickers are expensive. so that idea won't be used on future boards.

all of my graphics are template based with repeating patterns so they can be sprayed. i will try to get a screen printer to produce future templates. previous to this i have been cutting them myself on sticky back paaper with a laser cutter.

Gestalt said...

hi keef,

yeah i don't think adding wingers would improve the speed of your board. it would definately improve planing threshold but at 16mm i doubt you would notice it. 3-5cm overall and you would notice it. but then you would need to also look at footstrap position etc. now cutting wingers into the board would be worth a shot for improving top end speed. but as stated prviousy the extra thickness in the board you are using may be just to much of an issue to begin with.

what was it you didn't like about the original board?

my comments on extra width are aimed at building thin boards, where you still require a certain volume. you either put it in the thickness or make the board wider. this thread was talking about how to build a narrow board and still get extra volume into the mix without upsetting the ballance. (enter the term virtual volume)

my vote is for wider over thickness. problem with wider is that you create more drag. hence the stepped tails, wingers, cutouts, channels etc. other boards use tail kick but that requires more skill to sail as you need to set the board at the right apparent angle.

taking an existing thick board and making it wider still is only really improving the light wind ability of the board.

the graphics i did were laser cut vynil sticker decals with sprayed base colour and template sprayed black spots. yes the vynil stickers are expensive. so that idea won't be used on future boards.

all of my graphics are template based with repeating patterns so they can be sprayed. i will try to get a screen printer to produce future templates. previous to this i have been cutting them myself on sticky back paaper with a laser cutter.

i dont want to talk about those wings any more and the board is too narrow to cut into it, i origonaly had cutouts in the tail but it made the tail to loose so i filled them in with divi and reshaped so there like little concaves and that works
its not that i dont like the board, i love it but the rails were catching a bit on downwind runs in chop and 30knts thats scarry and there was to much volume in the tail especilly going to windward in chop keep up the good work on those graphics and im looking forward to seeing the mk2

Gestalt said...

Hi Keef,

I probably should have asked these questions at the beginning but

how narrow is the tail?

why was there too much volume going upwind? was it bouncing out?

downwind rail catching can be resolved with chimes or softer rails.

*edit* if the board is for a heavy weight and the tail is really narrow my experience of modifying boards is that adding extra width will improve the range of the board.

2350 long
the tail @ 300=370
@1300= 530
the rocker is 165 measured 300 from tail to the nose
the tail has tail lift 1mm from 300 to tail, then flat to 1300 if you measure the rocker from the tail its 4mm from tail to 1200 and 2mm at 700 the board has 4mm (thats either side) of v to 1300 then flat
as for the volume going up wind i think it was a combination of the back strapps out to far on the rail and tomuch volume on the tail ,or the fin could be set tofar back
ive sorted out the rails if you have a look at the pic of the bottom, the blue stuff is spray putty the black stuff is the repair just need to stick some balloons on tonight then i can sand it tomorrow
if you have a look at the measurements there unconventional and very flat but trust me they work the board is about 65lt
the job should be done in a couple of days, ill give it a sail if theres any wind then i consider thoses wings
,

mkseven said...

Keef actually wide boards are a bit the opposite- remember Formula boards are handled in 30+ knots in the chop. On wider boards you shouldnt be too quick to change down rig size as that power keeps the board in check. Where I have been quick to notice width is on water like that at burrum, where being flat you get too much lift from the board- it was one of the reasons I personally went to F2's over the falcon I had as the SX produces less lift at speed. I think you'll find that is one of the reasons why formula speed attempts are not done on flat water, no one will ever hold the boards down. So in short width gives you lift, chop gives you windage not lift.

Gybing there is so much more that affects it than width straight out. I noticed the width on 80 wide slalom and formula boards but under those problems were more about design where say a board bounces out of the arc etc. Again if you want something that gybes a little more like narrower designs go for a more rounded outline board with narrower tails etc.

With decreps 43cm board you really need to start looking at ways to keep everything low. I can understand the need for a board like that, alot would find it very hard to sail a board of that width with a bit of volume whilst off the plane. Personally i'v just gotten used to swimming

Width is definitely not a bad thing, it lets you have softer rails yet still retain great upwind performance. Even the awesome Vando suffered on one race ages ago where he'd damaged a board or something and went to one of his old 280's and he found he couldn't go upwind at all. A current 105 board has a much wider range than an old 105 design.

There were a few boards which have floated around with various hump shapes but not so much in the board itself- F2 required a hump for the airpipes on some models, exo and mistral (I think) played around with footpad humps. Along similar thinking about volume mistral had a stepped centre section of the board to keep volume where it was required and thin the rails out (under footpads was kept normal), from what iv noticed this design produces a really stable board off the plane.

i dont know how those formular guys do it big sails and big boards in 30kts doesnt sound like fun to me, i know what you saying mksevens about wide boards everyone is makeing them so thats enough proof for me, you know my board is designed for me and the conditions i sail" flat water" if it was a production board no one would buy it because its only for flat water ill tell you now its doesnt like heavy chop cos its to flat it gangs like a dunny door and slows down , but i have a rrd if i want to sail in those conditions

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it was one of the reasons I personally went to F2's over the falcon I had as the SX produces less lift at speed.

do you know if the fin is set futher forward and thats why you dont get as much lift at high speeds

your board doesn't sound that unconventional to me keef. sounds pretty sweet actually.

i thought it might have been to much length lifting the nose due to wind and chop but at under 2400 long it's probably not that. both MK and myself have taken hack saws to boards to tame them by shortening the length. works quite well.

also thought it might have been to much nose rocker making the nose lift while going upwind through chop. 165 is not to bad also.

also thought it might have been v but you've got plenty up front.

i'm tending to agree with your idea the straps are to far part at the tail. i too have a no rocker speed/slalom board which was built for flat water and it does tend to suffer spinout going upwind through chop. a couple of other guys have sailed it and we all agreed it was because the straps were to far out on the rail. i haven't moved them inboard yet to test that as i've been mucking around with the freestyle board. i gave the freestyle board back ready for the mk2 version so i'll be testing the speed board strap settings again next time it blows. it is a wide board though. but definately setting the straps right out on the rail can cause problems when loading up the fin on shorter boards. unless of course your using big fins and really wide tails.

on a board with a tail width of 37cm i'd be looking at either one strap or 2 mounted only about 3cm apart. use the 2 straps in slalom mode. for me a board at that width and shape is a 25+ knot board. with a swim at some point.

if you went to 1 strap it would be possible to cut a winglet into the tail. by re shaping it into a pin tail. that's if you still feel there is too much volume going upwind. best not to change everything in one go however.

setting your fin to far forward can also promote spinout. the front of the fin should be level with the back of the rear strap. or there abouts.

from memory and in general terms

the fin box should be about 100mm from the tail measured along the bottom.
the distance from tail to the mast track should be about 1250.
straps should be between 350-400 apart from front of rear strap to back of front strap. more on freestyle. 450.
although this one is not as common rear strap around 230 from tail.
strap inserts 150-160 apart.

when you start to measure up different boards you find that give or take they are all the same setup of boxes, straps etc.

hmm fins are black magic in my mind. i have to agree with mk that on flat water the lift becomes more of a problem at the tail. up at burrum i was talking with some of the top guys about fin selection. i noticed watching everyone come down the run that the guys on 30cm fins were starting to look a little out of control at times. the guys in control were on 25-27cm fins. so i asked some of the guys over a beer and it was agreed that in chop they use bigger fins than on flat water as the lift is greater on flat water. same would also go for tail area as mk said.

helping wide tail boards gybe can be done a few different ways. i like heavy chamfers at the rail or a step near the rear strap.
JP tend to increase the curve of the rail plan outline from about the middle of the strap positions to the tail on some of their boards.
angulo went for the wingers. all of them work in my mind as it's the area between the front and rear strap that controls the lift for early planing and drive out of gybes.

the formula speed sailing was a favourite of mine for a long time. i tried in choppy and flat water and think i got a max of 28 knots or somehting. i did have problems in 20+ knots with an 8.5 keeping the board on the water so asked a few of the pro guys what they recommended. in the end it came down to longer harness lines and rigging big. they all said that anything under 10m wasn't enough to keep the board on the water and choppy water presented the best surface for speed sailing.

a long ramble i know. but there's no wind anymore up here. so to recap.

yep, move your straps closer together at the tail.

edit* p.s. i forgot to mention. i like really soft rails on speed boards up front. like excessively soft. personally i think chimes are better for slalom. but not everyone may agree with that.

nothing beats trying it so i'd definately go with the winglets. it should help with the bigger sails for sure. but 7m is very big for that board.

the first change i reckon worth investigating is the tail outline. it's an old school tail currently and needs more of a pin outline. board gybing could possibly be improved by making the outline more curved by turnig it into a pin or even a diamond tail. that will also reduce the area and drag at the tail. i kinda like the theory of increased arc in the plan shape at the tail to improve gybes.

also 900 flat is long for a flat. 600mm maybe better and will again help with gybing but i'll ask some gurus about that. will get back to you.

keef said...

gesty ive done all the things you said, chimmed the front rails moved the front and back strapps inward but theres an extra hole on the front one to go outward,i use c3venom fins 28,30,36 the fin in the origional pic is a 32 that came with my CA55 i use a 6/7 rs6 a 5/8rss mk11 and a 5/0 concept the best time ive got is 30knts but thats cos i wasn't confident with the rails , ive managed to take 10mm off going down to the front strap, i remeasured the rocker and its flat from 300 and 1mm at 900, the board bogg's down when jibeing with the 6/7 but with the 5/8 and 5/0 its a different story so i need a bit more volume at the track and nose for the bigger sail, i'm still going to stick those wingers on just to see if theres any difference , you know with a board that size 16mm is a big difference, i have h80 divi ill just glue it on with vac shape it then bogg no glass shouldnt add to much weight and if it doesnt work ill sand them back , remember this is a proto so keep the suggestions comeing

900-1200 flat was what you wanted with old longer designs, the new ones are a bit shorter.

Keef sorry can you recap the dimensions of this board- total width, volume etc. Is this intended for speed or slalom?

BTW your smallest fin is too big

mkseven said...

900-1200 flat was what you wanted with old longer designs, the new ones are a bit shorter.

Keef sorry can you recap the dimensions of this board- total width, volume etc. Is this intended for speed or slalom?

BTW your smallest fin is too big

the dementions are
length 2350
tail width at 300 = 365
max width at 1300 =530
tail lift rocker 300 to tail =1mm
the rocker from 300 to 1200to = 1mm
the rocker from tail 1200 is 4mm
mkseven i know what your saying about the old flat rockers, but i have ridden the board and the plan shape and the rocker is perfect, the only thing is that it slapps heavy chopp i would need a bit more v and rocker to sort that out, up untill now ill jump on my rrd it it gets that choppy but i appreciate any input
the main reason i want to put those wings on is to compensate for the volume ive lost in recessing the foot strapps, besides i would like to know what they doo
ill see how the board goes after the repairs and if the rails are still catching ill add a bit of rocker infront of the fin its easyer the add ill be makeing another board after ive sorted this one out
ps i need the 36 fin with the 6/7 to lift the board out of the water

Gestalt said...

keef i had a chat with a shaper today about rocker.

his preference for speed was for continuous rocker. approx 10-15mm from the boards balance point and about 150mm nose rocker from the balance point.







also looking at your rails i think they are way way too sharp. i'd soften then off either with a freestyle type tuck ie. 60/40 apex (my personal favourite) or a decent chime. the difference between chime and tuck is more about upwind. i find chimes allow railing of the board for upwind performace where as tucks require the board to be carved upwind.

gesty thanks for pointing out the cutouts but ive sorted them out (thanks to gesty)

gesty if your shaper friend has a computer canyou get him to have a look at this pic , i have a brick sitting on the level and its actually flat to about 350(see the daylight under it )then its 5mm at 1200 so if your shaper is right that meens the flat planeing section from the tail is 350, so now were achiveing something, your rite about the rails, they used to be tucked but i had to take out about 10mm for the chime,but that will be sorted but if you have a look at where you can see the tuck they are absolutly ferfecto gesty as i said i dont have a problem with the speed ' i allso would like to point out that this board isnt a speed board, its a fast flatwater blaster,
with my CA55 i have noticed the wake starts at about the front strapp well with this board its comeing from inbetween the front and back strapp and this boards front strapps are 40mm futher back, it just loves sailing off the fin so once its on the plane its on the fin

kato said...

Hi ya Keef, don, t make the cut-outs parallel with the fin, run it at about 3 deg. I tried this on my old speed board, worked much better (less drag) at 3 deg. The rocker line sounds like it’s too flat. A little tail rocker might help.

thanks kato you meen 3 deg to the center of tail, i can rout out 10mm and theres another layer of glass, its all in place, but im a bit hesitant cos its only a small board and deeper cutouts made the tail too loose last time
that rocker in the pic is measured from the tail and has 1mm lift for my sailing conditions the rocker is perfect, the only problem was there was to much volume in the strapp's and the tail, and the rails were catching on downwind runs, but if its the rocker being to flat maybe thats the problem , the board dosen't look to hot but i dont have trouble passing isonic's ,CA's,falcons once ive sorted a few things ill do another one, and one thing i will be doing is recess the mast track, pads and strapp's into the board and ill work the volume out from there , they say gimmics dont work but being practable does

hi keef,

yep he means 3 deg to the centreline of the board. ie. so they taper towards the centreline *double edit* like mr loves picture....


the channels on my boards also do this.

*edit* i should clarify this. the channels actually taper towards the rail as it's like the cutout but in reverse. still there is a taper.

anyone or decrepit do you think the rocker could have changed while it was in the bag because it was defernatly flatter yesterday, and now its settleing back down either as the weather is cooler or the resin is cureing because the rocker from 300 to 700 is lifting, where yesterday it was defernately quite flat @ 900
i had the bag pulling 35 pressure which is high normal is 25 but i thought i needed more pressure cos of the deep inserts ill have another look tomorrow if anyone has had this problem let me know
this thread is allmost done but ill do another post after all the changes and a test run, thanks for everyones input and the pm's you have all been a great help

Gestalt said...

hi keef,

yep he means 3 deg to the centreline of the board. ie. so they taper towards the centreline *double edit* like mr loves picture....


the channels on my boards also do this.

*edit* i should clarify this. the channels actually taper towards the rail as it's like the cutout but in reverse. still there is a taper.

thanks gesty and martin thanks to you guys ive got that same angle , but im sticking to the slight concave for the moment i have 2 layers of 5mm divi laminated so if i need to get the router and do the full job its all in place thay meens i can go 10mm deep if i need to thanks