The final "sign off" Masterblaster rough water slalom fins have arrived along with the first Slalom sample. Hot or what!. The Masterblaster fin is proving to be powerful and fast and has really good grip in rough, messy water. It,s now production ready along with the Wave fins , lots of testing to go on the slalom yet, that will be available first half of next year.

Nice looking fin! Would you say this is a solid stiff heavy back foot sailor type fin? Is this something you are doing on your own or with Tribal?
Where does it sit along side the Power Max? This one looks like it might have extra sweep/angle?

I guess the design brief would be similar to the Powermax, effectively a slalom fin that will behave in rough messy water...also powerful so you can go down a size. It will take a heavy back foot as it has a powerful foil section and is quite stiff. Built superbly by the Tribal crew in the Netherlands but these are designed by me...the Tribals designed by Chris.

I used both the Masterblaster 38 and 32 freerace fins in the last 2 sessions...awesome, they work just great. Really fast and super slippery without nervousness, rock solid. Excellent fins as good as anything I have used.

I am going to get a production order together in the next few weeks so if you are interested in a fin give me a yell and I will get it included. Details are on my Atomicsurf website.

I also used the elliptical Slalom 42 prototype and was extremely happy with that, very promising. I have made a few tweaks and another 3 prototypes are being built so i am pretty excited about testing these. I am having a lot of fun with this project .

Version 2 Slalom Fin prototypes are on the machine.

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mr love said..
The final "sign off" Masterblaster rough water slalom fins have arrived along with the first Slalom sample. Hot or what!. The Masterblaster fin is proving to be powerful and fast and has really good grip in rough, messy water. It,s now production ready along with the Wave fins , lots of testing to go on the slalom yet, that will be available first half of next year.

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effectively a slalom fin that will behave in rough messy water...also powerful so you can go down a size. It will take a heavy back foot as it has a powerful foil section and is quite stiff. Built superbly by the Tribal crew in the Netherlands but these are designed by me...the Tribals designed by Chris.

I have finally found time to update the website with the latest fin info including a little slide show movie....take a geek.

www.atomicwindsurf.com/fins

Latest Slalom fins just arrived from the Netherlands. Version 2 Elliptical, slightly wider in the tip and the foil section has been tweaked with the help of Java Foil. Pretty impressive lift to drag figures. Will be testing them soon.

Interesting how the pattern on the G10 is different on the top and bottom fins. Something all those hand shapers who use the fibre layout as a guide should be aware of. Not much wastage there on the blank :-))

What is the reason for the reduced chord at the base on the Masterblaster fins?

Could be in my CAD file..need to check.

Idea behind the narrower chord in the bottom half is to reduce nose lift but it only worked with a thicker foil section,,,first prototypes were too thin and soft. I have been testing them on Port Phillip in the mess and they are working great.

Yes..memory jogged and i fixed it after I saw this photo for the first time.

Unfortunately due to an MCL tear I am off the water for a bit which really screws up my testing program. So I am after some help to test the Slalom V2 36 and 40 prototypes.
Qualifications...
IQ high enough to give me some usable feedback
Will sail regularly over the next 4 to six weeks.
Have some high end fins to benchmark against.
Uses GPS.

If interested in helping me out please IM me.....I will need the fins back when my knee is fixed.

Thanks Martin

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mr love said..
Pretty impressive lift to drag figures.

Hard to find real numbers for a windsurfing fin's lift to drag anywhere on the www. You're not keeping them secret are you?

For the record I have sent Ian the Polar graphs....I do not want to post them here as I don't have the time or energy for the inevitable arguments over the numbers. If you are truly interested IM me and I an happy to share.

Regards Martin

Some testing of the elliptical slalom fins has been happening here on Port Phillip, so in choppy water. Very encouraging so far. Feedback has been that they have a large sweet spot, turn on straight away and don't become unmanageable when overpowered. Very spin out resistant and forgiving. Upwind is excellent.
So we are meeting the design brief so far. Some flatter water needed now to really explore the top end speed so hopefully we will get some Sandy Point sessions in soon.
I will be back on the water next week to do some back to back testing myself.....

Martin start getting into Speed Weed fins seeing that's where everyone is sailing nowdays.

Yep it appears so. Not everybody sails in weedy places though.

First production fins have turned up...nice.

I used the Production Masterblaster 36 today in the Masterblaster 66 today. WOW....what a combination. The fin is brilliant, rock solid and fast. It was choppy and windy at times, pretty overdone and it never felt like letting go. In fact I tried really hard to get it to spin out and eventually succeeded in a lull when I was struggling to keep planing. I am really stoked, it has taken many, many prototypes to get here and I now think i have a pretty special freerace / rough water slalom fin. The combination was just brilliant along with the proto 2020 KaRace .
Now I just need to get my fitness up to the level of my gear!

Great work Martin, really like the look of the masterblaster freerace.

Been busy....

I have had some interest in experimenting with Assy side fins on my fusion board, something frankly i don't have experience with so was keen to learn and try. My understanding is that assy fins can increase the drive and grip through the turns but there is a downside to this, they can be draggy and unstable in a straight line . As far as i could see most Assys are flat foiled on the inside and generously foiled on the outside, a foil section like that is high lift / high drag.
As a starting point I tried to draw a parallel in the aviation world that had a similar set of demands as wave sailing and pylon racing came to mind, high speed and aggressive hi speed turning in a confined space....sort of feels like the wings would have similar demands on them as wave fins. I might be smoking crack but it felt like a good starting point. The more I looked I found a lot of work in the model plane pylon racing area, many people designing wing sections. Most of the work was based on an older section RG14 or RG15 which is still highly regarded. So I started there.
In xfoil run at Ncrit 2 and Reynold numbers between 1,000000 and 1,400000 it had very good lift to drag on the leeward fin and surprising good on the windward however I felt it was overall a bit draggy and I also wanted to improve the stall angle on the windward fin. So I made it a bit less aggressively assy and played with the foil section a bit to lower drag. When I ran the numbers on this revised section it had done what I expected..the L/D had degraded on the leeward fin but improved on the windward side and overall drag had reduced. The section I ended up with is 8.6% at 32% and has a camber of 1.47% at 37%.
Heres the polars compared to my slalom fin section.



So I modelled it up and will get a set made to compare with my symmetrical design.




Could be interesting!!!!

I have multi asymmetrical fins, as you said the basic inside foil is flat, from there many variations , true surf fins have some very sophisticated inside foils. Fins with twist near the tip are rare but still out there.
you assessment of how they work on the water is aligned with my thinking , no everyone likes the feel.
You didn't mention any toe in on the fin or boxes, this will eliminate some of the drag.

The board has the boxes set at 1.3 degrees tow in . I wanted to test apples for apples before i played around with extra tow in.

Heres the section

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mr love said..
The board has the boxes set at 1.3 degrees tow in . I wanted to test apples for apples before i played around with extra tow in.

I've found that using 1.5-1.75 toe is optimal, and doesn't effect dual fins that I can tell. My Witchcraft has 1.5,
the fins are only slightly asymmetrical.

your fin has a distinct rounded nose , it far from radical, having a round foil on both sides, it's asymmetrical for sure.
my POV is a very moderate asymmetrical foil. May be just what the doctor ordered. It's all feel on the water.

Theses bases fit my ProBox , which I use on most conversions , they are extreme, with convex inside foils and curved tips.

For me - every time Ive ever used symm production fins - the board loses so much performance riding waves , grubby moments bottom turning , niggles , rail trips , bad turn initiation etc .... Ive tried so many many boards with symm fins ( i run big quivers / go thru alot of boards) - ALWAYS find assy fins , either modified surf fins , or good old k4 ezzy fronts - work so so so so much better in proper riding conditions ... run 3deg ezzy k4 fronts in parrallel no toe / 0 toe boxes - or 1deg in custom boards with boxes at approx 1.6-1.8 deg ... My feeling is sometimes running assy fronts makes the boards perform as much as 40% better .... there's only been 2 production boards Ive preferred with symm fins , in the bigger volume sizes (89 / 92) - one with an aggressive double concave shape , the other with a single concave - interestingly both boards had tail 'hips' / kinks in the outline and just didnt like assy fins in general - but the smaller models in their range DID -and again felt much better with assy fronts .... I just dont get windsurfings obsession with symm fins - and if your running them right - should be LESS drag . Ive recently sailed tectonic fronts - and they were off the scale AMAZING - just loosened up some fast rocker thrusters to an amazing degree and took out all niggles / glitches - tectonics have the curving IN tip like the witchcrafts ...

Thanks Seabreezer. First is to test the fin at the same tow in as the symmetric, apples for apples so I can understand how the foil section behaves compared to the symmetrical section. Then I can play around with extra tow in. If I go straight to "one with the lot" then I won't clearly understand if it is the foil or the tow in that is the major contributor.

I very quickly think that I would get a set of K4s with max toe, 3 degrees*, and test them side by side.
* think these are actually a little less, like 2.75.

k4 asymmetrical are much flatter than yours , the nose only slightly curved.

There has been quite a bit of talk about 3D printing fins. I saw the Markedforged machine at the engineering show and it got my attention. The machine is capable of laying carbon rovings into a print. I bit the bullet and got a side fin made just in the standard carbon filled material ( no extra rovings) to see what it was like. The material is called Onyx and is meant to be the stiffest 3D print nylon material you can get??



Well the material is way too soft so would definitely need quite a bit of additional carbon rovings added. The finish is average, you can see the big "sink" along the trailing edge.
Conclusion.....The tech is not there yet, I am confident with the right amount of added carbon it would be stiff enough but the surface finish is not good enough. Then the cost.....well it is BS, way off the mark.

My opinion is it will get there in a few years, but not there yet.