Forums > Windsurfing   Gps and Speed talk

Advice for new speed board please

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Created by decrepit > 9 months ago, 4 Jul 2008
decrepit
WA, 12134 posts
19 Aug 2008 9:31PM
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Made a little bit of progress in the last week, the bottom's on, now it's time to start on the deck and rails.



I'd like to get the mast track as low as possible, think that should give better leverage, stability and close the gap more.
Trying to decide if it's worth while making a well for it, if so it would just be deep enough to allow the rig to go horizontal without mast extender etc hitting the deck.
Would a well that deep hold water?

I don't think it would, once up to speed, most of it should get bounced/blown out.

Any body had the mast track in a well?
Any problems with it?
Did it improve things at all?

mathew
QLD, 2045 posts
20 Aug 2008 12:16PM
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Early formula boards had a part-recess for the mast base, to flatten the deck around the base. On my formula, it has some of the deck scooped out, to thin it out and reduce its volume -> water does collect, but its not a problem.

Having a recessed mast track is probably a good idea, although you need to think about the deck-surface when the mast is lying flat on the water -> the deck can get dinted.

Aside: from looking at the pic, it appears that you might be dragging that rear-edge as it might have enough clearance...

mr love
VIC, 2352 posts
20 Aug 2008 2:17PM
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Most *Board Formula boards have a well ,never seems to be an issue. Just run it out gradually rearwards and it should self drain no probs.

decrepit
WA, 12134 posts
20 Aug 2008 6:41PM
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Thanks guys, I'll give the well a go.

mathew, the cut outs are 2cm deep and about 3cm wide, to me that looks enough, although I haven't made a close study of my wake at speed.
It's a bit late to change it as I've now got coremat in the cutouts. Guess I'll see how it goes, although if I am going to change it, would be best to do it before I go any further.

Any thoughts anybody.

decrepit
WA, 12134 posts
25 Aug 2008 7:57PM
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OK, I've made a start on the well, it's about 2cm deep. Mast extension at right angles is 3cm above base plate, so 1cm should be enough clearance.
Can anybody see any problems????



I've blended it in lengthwise for drainage, not sure about crosswise for glass-ability and strength.

kato
VIC, 3400 posts
25 Aug 2008 10:12PM
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Decrepit are you going to flair the well out to the rails? Ian Fox has wells on most of his boards to keep the center of balance(effort) down as low as possible.I,m still not sure if there worth the effort of doing ,I think cutouts are worth doing on the right board. Made mine perform a lot better.Good luck with it all


hardie
WA, 4082 posts
26 Aug 2008 8:44AM
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decrepit said...


Can anybody see any problems????






The major problem I see with it Decrep, is that I won'tbe owning it

mr love
VIC, 2352 posts
26 Aug 2008 11:42AM
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Hi Decrep , Sorry I can't help being a designer ****er . Purely aesthetic bit I think it should look like this . Run the recess right back to the front of the front pad and a bit further forward. Give the outside intersection line a bit of curvature so it runs better with the outline of the board .
My 2c's worth and I won't even charge you my consultancy fee!

decrepit
WA, 12134 posts
26 Aug 2008 1:39PM
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Thanks guys,

Kato, no I don't think I'll flair it to the rails, I'll loose to much volume thru the middle, could make it a bit weak as well.
Because I've made the back of the board thick to get extra leverage, I thought the well may help to compensate for the loss of stability, with the added advantage of still more leverage and less of a gap at the foot of the sail.
The whole board is a bit experimental, as Nebs said, you'll never know how it works unless you build it..

Mr Love, yeah that does look heaps better, I've and idea the more tapered sides will spread the loads on the mast base better as well. (May be why other people flair them to the rails?)

This arvo I'll attack it again, and post my progress.

mineral1
WA, 4564 posts
26 Aug 2008 4:08PM
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decrepit said...

Thanks guys,

Kato, no I don't think I'll flair it to the rails, I'll loose to much volume thru the middle, could make it a bit weak as well.
Because I've made the back of the board thick to get extra leverage, I thought the well may help to compensate for the loss of stability, with the added advantage of still more leverage and less of a gap at the foot of the sail.
The whole board is a bit experimental, as Nebs said, you'll never know how it works unless you build it..

Mr Love, yeah that does look heaps better, I've and idea the more tapered sides will spread the loads on the mast base better as well. (May be why other people flair them to the rails?)

This arvo I'll attack it again, and post my progress.


You know whats going to happen with this dont you, it will work great and we will all want one[}:)]

Pugwash
WA, 7671 posts
26 Aug 2008 4:52PM
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mineral1 said...

You know whats going to happen with this dont you, it will work great and we will all want one[}:)]

Can we hide a few lumps of lead in the foam to slow those Mandurghastan Mobsters down a little[}:)] Or, Pinnas could just keep poaching their team members

evets
WA, 685 posts
26 Aug 2008 9:35PM
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I hope you are going to be able to produce a few of these Decrepit

decrepit
WA, 12134 posts
26 Aug 2008 9:47PM
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evets said...

I hope you are going to be able to produce a few of these Decrepit


Well I've probably got 10 years building time left in me. You'll just need to be patient.

Yoyo had a good idea, just add a false smaller bottom to an existing old board, only problem is the added weight, but if the old bottom is removed first, might not be too bad.

hardie
WA, 4082 posts
26 Aug 2008 9:53PM
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decrepit said...


Well I've probably got 10 years building time left in me. You'll just need to be patient.





Do slightly obese friends with serious psychological problems get a look in

mineral1
WA, 4564 posts
26 Aug 2008 10:49PM
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hardie said...

decrepit said...


Well I've probably got 10 years building time left in me. You'll just need to be patient.





Do slightly obese friends with serious psychological problems get a look in



Nu [}:)]

decrepit
WA, 12134 posts
26 Aug 2008 11:23PM
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hardie said...


Do slightly obese friends with serious psychological problems get a look in



Of course, you look in most days anyway don't you?
(not inferring that slightly obese and psychological refers to you.)

sausage
QLD, 4873 posts
27 Aug 2008 2:41PM
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decrepit said...

OK, I've made a start on the well, it's about 2cm deep. Mast extension at right angles is 3cm above base plate, so 1cm should be enough clearance.
Can anybody see any problems????



I've blended it in lengthwise for drainage, not sure about crosswise for glass-ability and strength.


A master craftsman
BTW I was wondering why shaped ribs or v corrugated grooves (zig zag in section) haven't been incorporated into the decks of boards - just like Decrepit's board, wouldn't these ribs dramatically increase the stiffness (longitudinally) of the board . Down side may be the increase in surface area therefore additional weight issue.

decrepit
WA, 12134 posts
27 Aug 2008 2:32PM
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Sausage,
ribs should increase stiffness a bit, but would be a pain to make.
It's easier to increase carbon content to increase stiffness where it's needed, in the case of this board, between mast base and tail, don't think stiffness in front of mast track serves a lot of purpose. The rails of course form C section beams, they also are a big part of board stiffness.

Mr Love.
Good job you mention front pad, I marked it's position yesterday, and I'd already taken the well into it a cm or so.
Opened the sides out to the same curve as the rails, and it certainly looks better, but not as marked as your photoshop job. Think the angle of the photo makes the rail look more curved than it is.

I'm in the process of fitting the closed cell foam for mast track and foot strap plugs.

sailquik
VIC, 6094 posts
5 Sep 2008 1:53PM
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Ian K said...

OK, It does look good in a muscle car sort of way, who buys boxy railed Volvos anyway?


I did. Looking for another $500 'boxy but good' old Volvo wagon to replace the current rusting away one

Jamesy
QLD, 30 posts
8 Sep 2008 2:56PM
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don't know if you guys are interisted in this but over the past couple of weeks I have been thinking about a new speed board design which, in theory, would mean you don't have to go and look for flat water to do your speed runs!!
the design is taken from a seaplanes hulls which provide an almost frictionless situation when reaching a particular speed for take off. The hulls have been adapted to a 60' multihull:
http://www.parlier.org/hydraplaneur/index.php
have a look in the photo gallery.

Some basic theory is that a pocket of low pressure is formed behind the 'step' of the hull that ventilates the rest of the hull behind it, creating a very low drag stiuation and the less drag you have the faster you go!! The 'V' in the front half of the hull acts like a wave piercer, and then the flanges on the side hold the spray and water down, thus giving it lift! so then you have the front of the hull generating lift and the back of the hull being ventelated, so efectivley the hull is hovering above the water and chop rather than skinning the surface like a windsurfer on the plane.
don't know how much of this will applie to speed windsurfing but the theory side of it sounds good.

and how is you new board going decrepit??

thanks
James

choco
SA, 4032 posts
8 Sep 2008 3:07PM
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there are custom step hull boards around but without the V in the front section


Pacey
WA, 525 posts
4 Oct 2008 11:03AM
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Jamesy said...

don't know if you guys are interisted in this but over the past couple of weeks I have been thinking about a new speed board design which, in theory, would mean you don't have to go and look for flat water to do your speed runs!!


Sort of like this?


This was the board I built and sailed for the 1981 Weymouth speed week, and at the time (seeing as there was no-one else competing) it was the Australian speed record holder.

sausage
QLD, 4873 posts
22 Oct 2008 11:42PM
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Decrepit,
How did that board turn out and has it been on test flight?

decrepit
WA, 12134 posts
23 Oct 2008 7:42PM
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Hi Guys, we've just returned from 7 weeks in Europe.
No windsurfing I'm afraid, the closest we got to that was seeing an old Wally hanging from the ceiling of a garage in Malta, and a couple of kites flying off a beach in the South of France, (it was only 5kts so I think they were just learning to fly the things.

The board's still on the trestles, after I've finished all the the backed up chores, (depends how much help in the garden/jungle my wife wants), I'll start on the deck herex, could be another month before it's finished, just in time for some wind I hope.

Pacey, that's an interesting looking board, what sort of speed did you get out of it????

Pacey
WA, 525 posts
25 Oct 2008 10:34PM
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decrepit said...
Pacey, that's an interesting looking board, what sort of speed did you get out of it????


Good question, you could either consider the board to be blindingly fast because it got within a couple of knots of the world record at the time.... or you could consider it pathetically slow as the world record at the time was 24.6 knots.

In truth, it would be hard to make any modern board go over about 25 knots with the rigs we were using at the time (unbattened triangular sails, stock mistral booms, fairly soft masts) so what the actual speed potential of the board was I will never know.

keef
NSW, 2016 posts
26 Oct 2008 10:31AM
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hardie said...

Select to expand quote
decrepit said...


Can anybody see any problems????



how's progress going decrepit (have you got any more pics)
the glassing is going to be a nightmare without a wheel, have you thought about glassing the steep's(deck as well),you can glass a 90deg angle with uidirectional(as long as the fibers are in the same direction) and a fiberglassing wheel, it's easy to move the fibers into tight corners and tight angles and remove air bubbles, im talking about the steeps not the whole board






Gestalt
QLD, 14393 posts
26 Oct 2008 9:51AM
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here is another take on the step design,





keef
NSW, 2016 posts
26 Oct 2008 11:28AM
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tell us more i'm all ears

Gestalt
QLD, 14393 posts
26 Oct 2008 10:52PM
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keef said...

tell us more i'm all ears


well i didn't build it. but i had a hand in the graphics.

i do have a 120lt version, not sailed much but performs equivalent to hypers,

i also had a formula version which i loved and sailed every weekend.

previous to that i had a oldschool slalom board wit ha channel step bottom, @260cm it suffered from nose lift. the shorter lengths though seem to really improve the board. the 120lt i have is 220cm long. the short length leaves it a little technical to sail. from the boards i have i think 235cm is a great length.

i haven't used the board in the pic. but i have the prototype of it. the proto was an oldschool slalom board that was recycled. was an interesting experiment.

the boards sort of float or hover. kind of.

they also turn very easily, i think the step really helps the tail stick. they also glide through lulls and have a very smooth ride.

i find the shape likes to be riden off the fin and powered right up.

the one in the pic and my 120lt board were built for flat water. not chop. they have very low rockerlines.

my formula board on the other hand had lots more rocker than the board in the pic and handled swell, chop extremely well.

*edit* - upwind performance is superb to.



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"Advice for new speed board please" started by decrepit