It is time to test out the double inverted bottom shape so I am doing a prototype Atomicsurf Fusion 65 to trial it. Peter Ross at OES has kindly offered to build the board and will take a few videos along the way.
It is what I call an All-Terrain board designed for maximum versatility and fun in a range of water states, bump and jump, blasting and small waves. This one is 65 wide, 230 long @ 105 litres. The double inverted V runs right through and terminates at the thrusters leaving a V tail. Pretty generous V right through. Peter will use his Carbon/Kevlar corecell construction which has been well and truly proved out on his boards over a number of years.
I am really excited to test it over Winter....Brrrr



Photo is the 60 wide.

Doesn't the JP Wave Slate also have the inverted panel V from mast base to front foot? Then panel V out the back?

Possibly...I would need to look at one.

Just looked at JPs site...nope nothing like it.... Wave slate is V /single concave /V

Lee....Just to clarify the bottom shape have a look at my scribble. The top one is the new board, double Inverted V. Pretty much a standard double concave setup but inverted V rather than concave.
The middle one is the previous version of the Fusion which is a V with a single inverted V channel that turns to flat at the fin. My issue with this is that the tail gets flat and it is a bit harsh in rough water.
The bottom is what it appears the Wave Slate does mid board, so quite different to what i am doing.

In the bag doing the deck lam...

What is the intended sail size/wind range for this board.

When I win the lottery, I'd love to design a few boards - not that I'm any good at it but I'm absolutely fascinated by the process. Thanks for sharing this.

I have used the previous version with 4.7, 5.3, 5.8 , 6.2 and 6.4. Was a bit sketchy with 6.4 but I had small fins in. I would say 4.5 to 6.2 and the sweet spot is anything with a 5 in front.
Wind range is really going to depend on the rider size, @90 kgs I was fine with 4.7 on PPB which is very rough, I would say its an up to 30 knot board for my size and can get it going in 18-19. the new bottom shape should revel in rough water.

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mr love said..
Lee....Just to clarify the bottom shape have a look at my scribble. The top one is the new board, double Inverted V. Pretty much a standard double concave setup but inverted V rather than concave.
The middle one is the previous version of the Fusion which is a V with a single inverted V channel that turns to flat at the fin. My issue with this is that the tail gets flat and it is a bit harsh in rough water.
The bottom is what it appears the Wave Slate does mid board, so quite different to what i am doing.

Whats the theory and also practical reality of the V2 hull shape?

Hardie, It is just another take on the tried and tested V double concave, just rather than the normal curved concave it is a flat panel inverted V. My thought behind it is that it should be easier to build accurately, hand finishing a curved concave that is continually varying in radii must be difficult to get perfect, flat twisting panels are easier.
In theory it has less wetted surface for the same depth concave but I would be full of s..t to say it would make any difference.
Nothing I have seen with all the analysis tools on the surface is telling me it will not work to expectation so it was a case of....well lets give it a go.
The single inverted v on the first version worked well but with the single channel setup and the inverted V running out in front of the fin the bottom got very flat in the tail and the board a little bouncy in the really rough stuff. This will not have that issue as the tail is still a generous V where the inverted runs out.

Mr Love, I really enjoy your board design, build and feedback stories. Keep em coming!

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paddymac said..
Mr Love, I really enjoy your board design, build and feedback stories. Keep em coming!

Love experimenting......just need some people to order some boards and fins so I can pay for some more prototypes

Love your work too !!
you should start making foil boards !!!

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mr love said..
In the bag doing the deck lam...

It is made out of foil

I need some new fins to go with the board so have redesigned my Fusion Fins. Gone is the NACA section and I have used the section I developed for the slalom fins as it has great L/D and a high stall angle,why shouldn't it work as a Wave fin? I think many fin brands feel constrained by the base width but I have made these a full width foil and held the same foil %. as the slalom fins . You can most likely run smaller fins as they will be high lift and very efficient. Can't wait to test out this combo.

hi martin.

of the side fins ive used for 2+1 setups . my favourites are the inside foil that futures do.

whats missing from the market is a soft tip canted side fin with inside foil made in glass or g10. (fcs base) glass is cheaper.

side fins with foil or flat i think work better as side bites in 2+1 setups.

Hi Justin....Yep I messed around with assy side fins. From what I could figure out you need to run hi levels of toe in with them to prevent your windward fin from having almost no lift when sailing in a straight line. I might be wrong but appeared to me you need to run 3 or so degrees toe in. Thats OK for a pure wave board but this is a crossover and I am still aiming for it to be fast in a straight line, that much toe in might be a bit draggy. The boxes on the board are set at 1.3 degrees . I might make a set of assys with extra toe in to test it....thanks for the suggestion.

i'm no expert on this stuff but my limited understanding and experience is this.

more toe in helps the board ride off the tail through the turn more and in doing so gives the board a looser or more nimble feel.
less toe helps the rail engage further forward during the turn and makes the board feel stiffer in the turn or more like it's on rails.

so mixing rail outline and toe in affects the boards feel and performance in turns.

When using more toe in as you point out you get more drag. with flat foil fins and more toe in you get slower speed and more looseness or liveliness. So to get the liveliness but retain speed a fin with inside foil can be used. shapers call it inside foil. futures call it V2 but it's basically a fin with concave inside foil and convex outside foil. great in surfing for more speed in small powerless waves but i have found that translates to shortboards and windsups very well.

If you are using a toe in of 1.5 Deg on your board then asymetric foils like 80/20 or 70/30 are probably better for sure. rear fins on quads have less toe and are usually 80/20. i have found running 80/20 rear quad fins as front fins on three fin boards feels fast but feels stiff. so i've ended up preferring 80/20 small side bites to loosen the board up. i get the rail to rail feel of a single fin but with a little more grip when things get hectic. also works on longer boards.

for a fast lively multi fin feel more toe with inside foil seem to tick all the boxes for me. I've stopped using flat foil fins completely as they feel too draggy for bump and jump blasting.

i kinda fee like this is an endless search. i have so many fins in lots of different materials. some built from some real masters. i would be keen to see what you find also.

p.s. i can understand why wave sailors in slower waves would prefer flat foil side fins to slow them down to stay in the pocket and loosen up turns.

I found a section that seems to fit the bill, modified it slightly and ran it in Java foil....very good!!! So I modelled one up. It,s a true assy foil shape 8.9 % .

Modelled a fin up and will try it, do back to back testing against the symmetrical fin.

what are your thoughts on sd7037 foil.

was there someone doing assy speed fins with concave foil to one side.

Good L/D figures but is overall quite draggy. You would go smaller to reduce drag.

i dont have access to all the foils. is there something similar with less drag? that would be worth trying also on a fin with more toe in.

car spoilers use curved plates.

Race car spoilers are all about downforce .......yes drag would be a consideration, mx downforce for the least drag penalty but they can overcome that with horespower. The F1 cars have lots of resources to do the aero work and use all sorts of tricks like vortex generators and such. The small ones they put on decklids on production cars...they are about getting a clean release surface but many of them are BS and just there for styling .

That section you showed is interesting and you could overcome the drag by using a smaller fin as it creates so much lift. My search is for those high L/D figures in a low drag section.. Not sure this section would work practically for a speed fin though as you still have to sail back...except at Luderitz and I am wary of how usable it would be on the wrong tack?

There are tons of fin sections at airfoiltools.com. Download Java foil and run them at various Reynolds numbers. This has been my starting point then when I get a section that looks promising I see if I can improve it by modifying. It generally ends up nothing like the original however it is great to have these sections as starting points and idea generators.
But be warned...you can burn s..tloads of hours doing this!!!

i thinkm the thread is getting off track. i'm talking specifically side fin applications.

the speed fin reference was about possibly using any concave speed fin info out there for side fins.

getting back to the sd3037 foil is smaller overcomes the drag then maybe that's worth testing.

i guess my point is i have found side fins with inside concaves feel really good.

ill measure what i have just for my own understanding. im also currently measuring rocker, outline and fin setup of my boards.

NP...yep a bit off track...it is about the board. Hopefully an update on that soon, this arvos job is doing the sticker artworks.

Thanks Mr love - might be silly question but how do you shape your fins

Do you buy blanks with base fins systems already done or is that part of shaping process?

Normster, They are made by Tribal fins. CnC Milled from G10 Fibreglass sheet.

The next stage for me on the board was to finalise the graphics. I reworked the concept sketch to include Peters OES logo and then built the full size artwork for the vinyl print. Pads are made and the fins are on the mill.
It's all go!!!

Yeah baby...... it will be in Melb soon then all I need is 20-25 knots.

It;s in Da house and is superb, awesome work Peter. Next Monday looking promising!!

Nice. Now...... is the body ready