All the original FCS fins connect to the board in the same way so I wondered what other innovations could come from thinking just a bit more…
I imagine a thin shim of aluminium, glass or injection molded plastic, hell why not 3-D print it, something thats maybe oval, that sits flat to the board with a rectangular slot for the front tab.
On the outside of the oval is a ‘supercharger’ style of small fin.
so you align the shim over the front plug, push the fin in and the shim is held in place.
With a longer Oval shape to accomodate both fin tabs, it might even work to provide an '‘fairing’ curve to the base of each fin…
Maybe even a dual supercharger version for centre fins or for a longboard single fin.
Or a mini Butterfly fin for in front of a single tab Knubster.
Or looking at the last 2 pics, maybe create an item thats held between the two tabs and the board.
There’s only 2 surfaces to this, the flat plate that sits around the front tab, and the fin.
Pic 1. So I did a few rough plans on the flat plate design, working out the angles and dims to replicate the same idea on a standard surfboard.
Pic 2. After the first drawings, its time to refine the lines and work out what’s essential and what part of the design can be profitably modified.
Pic 3. Now the flat plate outline is smooth, minimalist, and positioned around the front tab and under the front half of the side fin for maximum stability.
i find spending more time thinking thru the design saves a lot of time, rather than later building unworkable prototypes that just needed more thought.
Just working offa the basics , I’m going to have the same ‘toe- in’ as the side fin…Pic 1.
Keeping the alignment parrallel just makes it simpler for testing and pushing the new fin forward keeps its base away from the ‘tuck’ of the rail… Pic 2.
Looking from the side, with a small fin that’s set back from the front tab, there’s no overlap of fin template or dynamics…pic 3.
But with a generic 3 or 5 series fin there’s enough fin overlap to expect some interaction between ‘major’ and ‘minor’ fins…pic 4. Might even rake the minor fin a bit more…
I’m also afraid that it will damage your fin or finbox when it breaks (and it most probably will break).
when your fin flexes, the anlge of attack will increase (because the pivot point is behind the fin). When the angle of attack increases, the lift force increases, which makes the angle of attack increase, … you get the picture?
Please don’t let this stop your experiment, maybe I’m wrong and this works great. But don’t try this with you best fin and board.
I say go ahead with it brett , ignore people’s opinions , and let us know how it rides , eh ?
and… if it is an improvement to the board’s performance , GREAT ! [ if not …well , " nothing ventured … nothing gained " , as they say [whoever ‘they’ may be , anyway ?! … haaa !]
As you know , Brett … PRACTICAL EXPERIENCE is what it is ALL about ! [ whereas ‘opinions’ , without experience [ and , possibly 98% of the time they’re NOT based on experience ! ] , are just that …"opinions " ! …And so they don’t mean squat , anyway ! ]
Pic 1 and 2. Cut the outline with a few mmm to spare for foiling the edges, it’s only 1.5 mm thick but foiling every edge can’t hurt.
pic 3. The front tab sits neatly in the slot. If it’s not stable enough I can extend the plate to include the rear tab.
Pic 4. The minor fin has a degree more cant than the larger side fin. But I can change that + or -
Pic 5. With the flat plate cut and foiled Ive drilled holes in the fin panel, it’s not for weight reduction but for mechanical bonding between the panel and the resin, micro ballon mix to create the fin thickness and foil.
Hi Ben, yes its made of 1.5 mm Aluminium, light, strong, easy to work with.
The Al is more likely to bend than break and when /if it bends I’ll get a better idea of the size and direction of the forces during surfing. I can always change the shape / size of the fin component.
I put the microballoon mix on last night so this arvo I’ll sand it down and then its ready for testing.
Luckily the FCS grub screws go in and down at about 32 degrees so as the screws push onto the tabs, they also push the fin down to hold the flat plate to the hull.
Im only making one of these to test on a board with one standard fin and one with the added supercharger.
Trying it with different fins shows that the dimensions of the tabs on different fins are quite varied. Its likely I’ll need to extend the flat plate to include the rear fin tab to create more stability. ( see last 2 pics.)
ive done some fairing on the inside base edge, its not essential on the outside edge.
…they also look like they ‘glo’ in the dark , in some photos ?
DID you use some of the glo powder , for it ?
also ,
how is the gap between the bottom of the board , and the base of the fin , with the ‘insert’ in place ? [ is there a way to make the insert reallllly thin , so the rear fcs tab will also still sit flush to the bottom of the board , Brett ? ]
final question [for now] …
“captain caveman” / alex bud …will he test pilot these for you , so some ‘standup’ results will be possible ?
