Another one. Basically I am over full blown Race gear on Port Phillip Bay so this is a fast freeride, the bigger bro to the Phil Carbon board.
A revised version of the mono concave /flat V bottom I did on my Blue Slalom board, the shape works and this is just a development of it. The board has a bit more tail rocker and nose rocker, slightly narrower at OFO and thinner in the tail than the Slalom board.
Designed for blasting, cruising on the north end of Port Phillip with it's steep breaking chop/ waves in 7.0 meter plus conditions.
Going to use KA Kults and Koyotes on the Bay this year also for much more cruisy after work sailing than I have been doing on the Race gear. I must be getting old!!!

236X70X114 litres. Single concave to flat at OFO. Flat V either side of concave, constant angle to 700 off then increases forward. Subtle extra V side panels start at 800 off and increase the V forward to lift the rail a touch higher and prevent catching. Scooped out deck with lots of volume placed at and forward of the front straps so floaty when dogging it with the thinner tail making it less prone to bouncing through the jibe.

Board will definitely not be full carbon for a softer ride. I will still keep the Blue slalom for flatter water venues as it is blisteringly fast, just want something tamer for my Bay sailing.

Some quick screen grabs. Concaves not as severe as the look, it,s just the chrome shader

Any volunteers to build it for me???

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mr love said..
Any volunteers to build it for me???

Have you run out of people that want to do one-offs for you? You must have used every custom board builder by now

It appears I am too difficult to work with, prima donna designer

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mr love said..
It appears I am too difficult to work with, prima donna designer

a bit like architects that don't know how to build houses

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mr love said..
It appears I am too difficult to work with, prima donna designer

Maybe its time to try it yourself and get a feel for the pain you cause?

Surely it can't be too hard.. is what you would say at the beginning.

At least you have learned that a high carbon board is sometimes too stiff.

Between my paid job, the KA sail design, messing around with board designs and occasionally going for a sail I rarely see my family, it's amazing my wife still lets me in the house. Somehow can't see myself learning how to build boards!!!! and not sure I would have the patience for it even if I had the time. I would screw something up, spit the dummy and put an axe through it.( designer temperament!!)
Think I will leave it to the experts.

Adjusted the nose rocker down some and in the rebuild the volume has crept up a bit, 116.5 litres. Still in the range I wanted so finished as far as I am concerned. Now to get it built!!!!

I'm surprised we're not 3D printing boards yet.

looks great Martin. Hard keeping up with you on the last few boards. Maybe you can sacrifice some speed for comfort In this one

Nice Marty ! Whats the advantage of the single concave compared to V with double concave ? I just picked up a 2008 Falcon 89 which has a single concave in the rear tapering out to a flat tail which is intriguing to me.

Haggar, Good question and I am not sure I have a real answer and I assure you there was no real science involved with this.. Just a bit of background.
I am Exterior design manager at GM Australia (Holden) and a car designer. Now I am in management I am not so hands on with the designs and spend lots of time in meeting rooms trying to avoid death by PowerPoint presentation. I doodle a lot on my note pad during meetings. A few years ago I found myself sketching this board over and over again, single concave up the middle with V either side, it was stuck in my head. So I made the decision , !@#$% it I just have to try one and see what it does. So the blue slalom board Stuart made me shown below was the result.
At first I was mixed about it, seemed no better or worse than than standard V double concave and the more I thought about it the more disadvantages I was conjuring up in my head. However it appeared really fast. The disadvantage I could see was that as you run the concave out between the straps you end up with a spot where the center of the board is flat and that concerned me as I thought the ride may be too harsh. It also meant that if you want to get the rails higher than center-line to help prevent them catching you needed to run higher levels of V on the outer panels than you would if the V ran to center-line. However this does not appear to be an issue as the center concave seems to generate enough lift to compensate for the higher V in the high lift area of the board.
Advantage, the only one so far I see is that the board appears to sit very flat laterally and doesn't seem as sensitive to weight on the rail to trim it. It also goes upwind really well and this could be due to V side panels, not really sure but it trucks upwind.
So the bottom line is that it was an idea I had to try just to see, no real reason other than curiosity. It appears to work, no better , no worse just a bit different. I want to give it another shot with a few refinements. My main issue with the blue board is it is full carbon, super , super stiff and the ride is a bit harsh in the rough water we have at the Northern end of Port Phillip. The design handles the conditions fine and when I put the hammer down it absolutely fly's but it is not a relaxing board to sail due to the really stiff construction. I am not getting any younger!!!so I want a board that is not full carbon on the bottom and a bit more forgiving. Also this new one has more tail rocker and is thinner in the tail to make it a touch easier to turn and more forgiving through the jibes. I have run the concave a little further rearward on this one also to theoretically soften the ride a touch more between the straps. It is overall a touch less racy in it's design and hopefully a bit more cruisy. It should hopefully still be very fast but that was not the overriding objective.
I will keep the blue board for Sandy Point and any other flat water venues I sail at, it is really fast and awesome to sail in flatter water. This board will be in the back of the wagon for sea breeze sails after work at Pookipa or Beaumaris, a bay board.

I have not taken a good look at the monoconcave between the straps on the Fanatic so really can't comment on the why's or maybe's, sorry.

Evan, it is not the board but the awesomness of the person riding it and those brilliant KA sails I use ( shameless plug!!!)

Thanks Marty for that great overview. I'm told that the Falcon with the single concave does ride high and is efficient and slippery so I will see, maybe some minor similarities with your concept, it will be interesting to see how yours goes !

^^ I did have one of the single concave Falcons ( around 110 l) . It was one of the earliest planing slalom boards I have ridden. Once you had it trimmed just right it would float nicely above the chop and it was a fast board with great accelaration. There was a fine balance with trim, initially it used to take off vertical when you get it wrong. But once used to it it was a nice ride

If anybody is interested I thought I might quickly walk through how I build the boards in CAD.

The system I use creates NURBs surface off B splines, as opposed to a system like Maya where you start with a primitive shape and pull and poke it to create the desired result I start with a network of curves and build surfaces off that. This is the way we build car models (although we are now using Maya to do the fast concept models at the start of the process)
The first image shows the surface model boundaries and some of the curves I have used to create them. I have a set of standard rockers now which I then vary slightly depending on the board.
















There are really nice tools to ensure the curves are super fair, this is really important to building pure surfaces, it all comes from having the construction curves really good to start with.
The second image shows a surface skinned between the curves. I don't need to do too many sections as I have a lot of control over the surfaces I skin between by using a bias control which adjusts how much each surface boundary influences the surface.
The image with the stripes is one of the main evaluation tools I use to see how fair the surface is. Any wobbles in the highlights shows where there is a flat or a hollow in the surface and it also shows me what the transition is like from flat to curved. The last slide allows me to see the surface curvature. All these tools are adjustable. I can also project sections where ever I want and put curvature combs on those sections to analyse in detail.
I have done lots of boards now so have my methodology pretty sorted however every time I try something different with the shape it can have its set of challenges on how you build. it. Trial and error is still the best way!!!

Very impressive Marty. I can now that you can have confidence in your design if you are building on your previous ones and have a great deal of of control over that.

Only hassle I have with it is that the volume tool is only accurate on a finished closed surface with all the surface normals oriented the same way. That means I have to finish the model before I know exactly what the volume is, if it is over or under my target it means some rebuilding. You can scale to an extent but it distorts either the rocker or outline when you do that so not really the way to adjust volume. This is one of the reasons why I hollow the deck out as it is an easy way to tweak the volume just by altering the deck scoop.

Hoop has generously offered to build the board, in the process of organising all the templates to be laser cut for him so he can get going. Soon there will be a NUDE in the shed, COOL!!!!!!! Gunna need a bigger shed, especially as the boss says if I get another board I can sleep with it.

just make sure the vent plug is lined and big enough then Martin

I have a fetish but that is maybe taking it a bit far

here's my slalom race from the mid 80's the nose has a slight concave leading into a flat tail with side concaves starting a bit forward of centre , I remember making a sanding block simular to a fin foil with it being deeper at the front and very settle at the tail
there was a sliding mast track and sharp boxy rails to work to windward and at times a struggle , once you had reached the windward mark in planning conditions it was all over red rover
there is no comparison to the modern boards because I didn't have a lot of technology , it is simular to the bottom of your board , it's hard to compare because of different rocker and modern tech

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mr love said..

...The system I use creates NURBs surface off B splines, as opposed to a system like Maya where you start with a primitive shape and pull and poke it to create the desired result...

... not always. Here's one I prepared earlier. Much earlier - 2002

Maya 4.5 all NURBS. Although, my models are meant to be blown up, not manufactured :)

Cue Barny with a stick drawing of a windsurfer and a kiteboard.

Hey great thread, I've often thought of making a board with a huge single right through to the tail but put in twin fins at each side edge of the concave.
Im very envious that you can design and play with shapes in 3d on a pc and seeing the process of it designed in 3d is great to see.
I am curious though, as designing on pc is very acurate yet over the years I know what goes into the vacuum bag is not what comes out meaning that the pressures on the board and the pvc foam often can change the rocker. Do you check your boards after they've been made, with laser cut rocker and bottom contour profiles? If so how acurate are the finished boards to what you designed on the pc?

Ps nice Scooby shear tip

Generally they have been pretty good which is a testament to the skill of the guys building them. I won't say absolutely spot on but pretty close. I have seen some inaccuracy in the nose rocker, a bit lower than I designed on a couple of the boards but the guy,s have got the V and rocker very accurate in the back half.

Great work Shear tip. We are using Maya now for our initial scale model work, much faster than modelling in Alias for a quick look to see if the designs are working before we commit to a clay model. The feedback from the team is that you can only go so far in Maya and they struggle to get really refined surfaces and highlight accurately, but we are finding it a fantastic tool for getting the 2D sketch concepts into 3D quickly. You model looks very refined and detailed and I would be really interested in the amount of time it takes to get it to this level.
Might need you come to Melb and give my team some tips!!!

Sorry to hijack this thread everyone, just talk amongst yourselves for one more post...

Martin, I built that Subaru as a tutorial to teach people how to use NURBS. It was a well organised section of a website that's long gone, however luckily someone downloaded the entire site and made a pdf. It might be helpful for your team. It's mostly lofts, birails, trims and fillets - accurate enough for film and TV. From memory, it took about a week to build it from 2d reference images.

17MB download
http://mikethomson.com.au/tmp/Michael%20Thomson%20Subaru%20Wrx%20Nurbs%20Modeling%20Tutorial%20With%20Maya.pdf

Cool thanks. We have some of the Korean digital design team here next week to talk about this exact subject so I will share this tutorial with them and our team.

Back to the board..... templates are ordered so it's go!!

Laser cut templates on there way to Hoop.

Cool, looking forward to putting this jigsaw puzzle together!

I recently saw one of Hoops latest creations in the making and I'm sure your going to have a mighty fine board Mr Love

I have no doubt!!!!! that is on the assumption that my design is not a pig

Friggin truck didn't turn up, tomorrow I hope