This thread is a continuation of the previous Raceboard Design thread, which has become too long:

http://www.lbwindsurfing.com/board/gene ... esign-1015

Here's the new board from Exocet:

... and the new batwing phantom from starboard:

yagon wrote:Here's the new board from Exocet:

Hi Yagon- are you OK about the ip transfer/loss on this?

I understand the the Exocet will have the following specifications:

Volume: 355 litres
Length: 380 cm
Width: 77 cm
Width 30cm from tail: 65.9 cm
Width 30cm from nose: 21 cm
Weight: 14.5 kg
Fin size – box: 52cm tuttle + daggerboard 85cm

I understand that the SB Phantom will only be 263 litres.

Given the extra volume and the interesting D2 approach I am most interested in the Exocet. Only concern is that width. Will it be too wide to perform well in light winds? If it has the chines shown in the earlier pics it will rail well and avoid the issue of excessive wetted surface area I guess. Any thoughts?

Cheers
Pat

Rancor wrote:Hi Yagon- are you OK about the ip transfer/loss on this?

I am currently corresponding with Patrice Belbeoch from Exocet and will let the forum know the outcome of our communications when resolved.

Pat wrote:Exocet specifications:
Volume: 355 litres
Width: 77 cm
Weight: 14.5 kg

This big volume and wider board with a weight of 14,5 kg?
That will be a challenge for material, robustness and manufacturing.

It looks that Exocet is building a low wind and Starboard a strong wind board.
I am usually interrested in an allrounder.

yagon wrote:

Rancor wrote:Hi Yagon- are you OK about the ip transfer/loss on this?

I am currently corresponding with Patrice Belbeoch from Exocet and will let the forum know the outcome of our communications when resolved.

ask him what was wrong about the elite 380 if they are canning it after one year...

Full carbon I see and then sky-rocket price I suppose.. But very very nice, Div 2 like old division 2 boards...

WOW, While there is a box rule , this is more of a development class.
Do i like this? well i have very mixed feelings.
The Downside? , too much change is going to pee people off. If i bought a exocet 380 or a phantom 2 years old , I would not be happy ! These boards are expensive propositions.

The Upside? maybe one design shall rise above and prove to be a winner, people will gravitate to that design . but methinks NOT.... people like innovation , change is exciting, and the promise of a better board all nice and shiny ..SELLS!!!!

That being said, i shall remain happy , my the old f-2 lightning world cup race ( 250 litres) it is fast enough in a blow, good in medium, fair in light winds... BUT is durable and was the right price!
NO i am NOT at the front of the fleet , but close enough to be happy with all that extra change in my pocket!! time to book maui again.

I just spoke to the current Chair of the UKWA and he told me the use of custom boards at UK national level was passed by an AGM two years ago. It is a pity they did not post this on the national Raceboard Class page.
I draughted most of the original dimension limits to keep Raceboards "Flat"
I will now certainly build my hollow sandwich prototype . Narrow(66cm beam ) for less wetted surface not railed .A development of the very quick D1 I built 25 years ago
Roll on 2012
Regards PJE

johnnyfartpants wrote:I just spoke to the current Chair of the UKWA and he told me the use of custom boards at UK national level was passed by an AGM two years ago. It is a pity they did not post this on the national Raceboard Class page.
I draughted most of the original dimension limits to keep Raceboards "Flat"
I will now certainly build my hollow sandwich prototype . Narrow(66cm beam ) for less wetted surface not railed .A development of the very quick D1 I built 25 years ago
Roll on 2012
Regards PJE

Hi Peter,
I am interested how you design and build it.
Can we/I get some pictures or explanations?

I am thinking of doing it also (electronic design, CNC-drilled-hollow structred foam core, carbon sandwich, vacumm pressing).
But I need to consider what I can do myself and where I need professional help.

Kind regards
Knud Fischer from Germany.

Hi Knud
I just use good old fashioned Boatbuilding Technology with a few adjustments.
I have always built my boards in my workshop at the end of my garden (10 metres by 6 metres)
You will have to build a "plug" ,If you have access to a cnc 5 axis miller this is possible straight off a styrofoam block,without you will have to practice your shaping or build a traditional wood plug off frames. and then a Mould (GRP)
Fully Hollow can only be built from a mould using a suitable core (for example 8mm 60 kg Divnycell foam) double Vac bagged and whatever Fibre/resin skin you can afford .PVC systems work well with Poly or Vinylester resins.
I have been experimenting with 40 KG extruded styrofoam hotwire cut to 8 mm sheets with carbon epoxy skins and the sample panels perform quite well.
This material is used in wing construction in some light aircraft without problems
Double 250 gm carbon skins +resin vacbagged will weigh approx 1kg per msq. add core weight and paint finish will add about 0.7 kg per msq.
The surface area of a Raceboard hull is around 5 msq so a weight of 8.5 Kg is possible plus of course centreboard case and fittings,track etc.
The biggest advantage of Hollow is you can build very high volume strong shapes without a penalty of additional dead core weight and if(when) you hole them repairs are easy and the water empties out anyway.
Good luck
PJE

A followup article:

http://lbwindsurfing.com/journal/opinio ... d-design-4

There is a new SUP which as a wave-piercer-bow and skiff like shape
taken from the PUMA VOR World Ocearn Racer. Interesting Design, skiff like.

http://www.standupzone.com/forum/index. ... c=12323.30

I have been thinking about the Skiff-Shape and I do not know if that is the best to do.
The IMOCA Open 60 is designed so wide at the back and is therefore skiff-like. But it is designed to achieve
maximum stability downwind with only 1 man crew. Upwind this boats do not point high compared to fully
crewed Race-Yachts.

You need to differ between Upwind- and Downwind-Surfing.

Downwind the skiff-like supports early planning. But I do not believe that this works upwind.

I plan building a raceboard this winter and I have been playing with Freeship since I discovered the skiffboard that Yagon published. (Thanks Yagon, I had a lot of fun with it).
To exercise I first designed a Lechner A390 which I know very well (and sailed this summer). So I could check my design with a real board. ("poor stability" says Freeship :-) I knew that! ).
Next try was a wave-piercer bow with a classic stern and later Batwing tail. (When i find out how to upload a picture, I'll do that)

Has anyone tried something like this?
Are ship design parameters like "Wetted Surface", "Prismatic Coefficient" useful for Raceboard design? How should they be interpreted. What are good values?

Peter

Just a few points on my board's performance and how it might be improved from having used it, mainly on the sea off the coast of Cornwall. Lake sailing I think it is fine (Clocked at 26 knots on one and only time) and it proved its beating ability at the nationals. Downwind, 'modern' sailors complained that the bow would catch downwind in a swell, but I guess us more 'mature' sailors, brought up on custom Div I are slightly more use to it. You dont get something for nothing, and reaching the windward mark first is a good place to be.
1. Reaching or broad reaching, as one comes off the top of a swell at speed, I have noticed that if the bow drops, the rounded section on the bow of one side of the board suck down. It does not tip the board over but it is an annoyance. Sean's Chined bow as on the sabre would probably alleviate this and a chined bow will be tried on the next board.
2. The track needs to come further back,right back it is 1660mm mast pin to stern though this means either: (a) a skewed track (diagonal) fitted. (b) track comes back into centreboard slot but how to operate centreboard? (c) A curved track is designed to come down side of centreboard.
3. New high aspect ratio centreboard works very well and will forward some pictures to show how it was made.
4. Mylar Slot flusher- works but at the back of the flusher (stern) it folds up sometimes and jams. This is to do with the longer centreboard, and the angle it meets the slot flusher at on the end of centreboard. Very annoying ! Did not happen with old shorter centreboards!
5. Should have kept the volume in the nose but thinned the board down to around 165mm rather than kept the 200mm around mast track area. This would help with stability. Board is 630mm wide. Again will do this on next board.
Great to have this forum and see the ideas but look forward to hearing of other peoples board building adventures.

years ago i put a mastrack in a Crit D2, skewed/diagonal as you describe.
it worked well.