Forums > Kitesurfing Foiling

Inserts as an alternative to US box for foil mounts

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Created by Mokuleia > 9 months ago, 10 Nov 2018
Mokuleia
68 posts
10 Nov 2018 4:08PM
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Hi guys,

First off, let me introduce myself as I am new to this forum. Mokuleia, 39, surfer (15 yrs), SUPer (5 yrs) and kitesurfer (1 yr), leaving on Oahu, Hawaii. So "Hi" everyone!

I am in the process of shaping a new directional board that I would like to be "hybrid" kitesurf and kitefoil. I am currently debating about the mounting system for the foil. Ride engine sells a nice two-track system in HD foam that can be dropped directly into the shaped blank and glassed over. Nonetheless, I have seen other option, like the "Hybrid" by North (RIP ;-) where they used inserts instead of tracks (see below). I like the idea as it is less intrusive and maybe better for drag (although inserts offer no option for foil position adjustment, but that is another issue). My plan is to use the board mostly for kitesurfing (80%) and a little bit for foiling (20%) until I get good at it (at which point I will shape a dedicated foil board!)


I am curious to know if you guys have any feedback on this type of insert mounts as far as durability and maybe some thoughts to share about possible integration into my shape. I suppose the insert would have to contact somehow the deck of the board for maximum strength (a la FCS plug), and maybe installed into HD foam block. I also thought about using T-nuts in wood blocks...

Anyhow, any inputs would be very appreciated.

Cheers, Mokuleia

RAL INN
VIC, 2880 posts
12 Nov 2018 10:09AM
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Tracks are gaining popularity over inserts mainly because they allow that fine position tuning.
plus I think the drag issues are too minor to be really noticeable.
10" tracks at 90mm centres will let you cover all the good foils.

Livit
WA, 542 posts
12 Nov 2018 11:06AM
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There are many ways to do it. I personally prefer the tracks for the reason mentioned above.

Hybrids are a bit different though as you will probably have a bit of rocker in that area. Futures strong box has a built in rocker line making it a bit easier to adjust to shape.

I have replaced 2 of the ride engine/slingshot blocks due to broken fin box (on one of them the foil ended up at the bottom of the river), so I don't think I'll advise you to buy their stuffs. I may be wrong but the foam they use on that block didn't look like PVC. You should be able to make a proper PVC using quality fin box for less than the Ride Engine option.

Many will advise to use only Chinook as they are built stronger ( I used to swear by them but since they can be hard to get I had to explore other ways) however Futures seems to be doing the job fine and is a lot easier to instal.

As for the HD block, I don't think a deck to bottom insert is necessary but if you are building the board from scratch, you may as well do it...

Here is a SUP I am currently working on. I used a 30mm HD foam block. This SUP had a 5mm PVC sandwich laminate but the core was a very ight EPS. With using the 30mm HD block I was a bit wary that compression could potentially be an issue so I drilled a dozen 25mm pits that I filled with 80kg/m3 PU foam.









If you decide to use inserts, try getting something like "big head" inserts : https://www.bighead.co.uk/the-original-bighead/

Swavek
WA, 393 posts
13 Nov 2018 11:27PM
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BigHead are quality inserts but in Australia you can get them in packs of 100 only and the pack cost $AU 700. Perhaps one can get smaller quantity in US.

These are used by some in USA - not as light as BigHeads, but perfectly suitable and good price for a pack of 5




ActionSportsWA
WA, 950 posts
14 Nov 2018 3:25PM
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Hi Mokulaiea,

The reason why Duotone/North did the inserts as opposed to the tracks is to keep the wight down and to preserve the normal flex of the board. The tracks add significant weight to the board which detracts from the surfing feel of the board when not using the foil. Drag is another issue but is probably a lesser factor than the weight.

The Duotone surfboard Hybrid with inserts, is much lighter than the Slingshot Converter with tracks.

Tracks do give a nice element of adjustability to trim the foil perfectly for balance, but if you surf 80% of the time and foil 20% of the time, the Hybrid would be the ticket.

DM




Mokuleia
68 posts
16 Nov 2018 4:46AM
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Hi everyone,

Thanks for the feedback, I really appreciate your inputs. Some comments for each of you:

Livit: I have been looking into Future Fin's central boxes and really like the option. Also, I have the regular Future Fin kit for thruster box installation already. Do you think I could use it to route the box for these central boxes using a larger router bit and by sliding the jig incrementally? Or are the dimensions of the central box so different than 4.5" boxes that I would need to by the 1-shot kit ($$$)?

Swavek: great find! would you install these with the flange right under the glass (a la Future Fins boxes)? Also, would HD foam be sufficient strength-wise? Should I consider wood blocks?

ActionSports WA: thanks for the precision. This brings me to an additional comment about hybrid boards: the fact that the foil is mounted on a tail with rocker leads inevitably to the foil fuselage not being parallel with the board (see picture below). Is this problematic? Do people use some sort of shims at the foil/board junction to correct the angle? Just curious.


Livit
WA, 542 posts
16 Nov 2018 3:10PM
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Hi Mokuleia,

I haven't seen the one shot jig for the 4.5" fin boxes so I can't really comment. I would assume that the flange of the strongbox is wider than the thruster and quad box, wouldn't it?

Regarding the hydrid board, I reckon if you have the skills to build a board, you should just make a foil specific one. There is less work involved in the shaping and it is just so much nicer to ride.
A couple of years ago, I bought a hybrid for traveling and found it was just a horrible ride coming from a pocket board. Even riding 80% surf and 20% foil I wouldn't even consider one....

that's my 2cts worth

Mokuleia
68 posts
17 Nov 2018 3:01AM
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Select to expand quote
Livit said..
Hi Mokuleia,

I haven't seen the one shot jig for the 4.5" fin boxes so I can't really comment. I would assume that the flange of the strongbox is wider than the thruster and quad box, wouldn't it?

Regarding the hydrid board, I reckon if you have the skills to build a board, you should just make a foil specific one. There is less work involved in the shaping and it is just so much nicer to ride.
A couple of years ago, I bought a hybrid for traveling and found it was just a horrible ride coming from a pocket board. Even riding 80% surf and 20% foil I wouldn't even consider one....

that's my 2cts worth


Hi Livit,

Yes, it looks like the future fin central box is larger, so you are right, the "regular" jig will probably not do the job. I will try to see if I can doctor up something though, cause $200 for the kit (without the router!) is a little steep!

I am also leaning toward making a foil dedicated board after all...as a matter of fact, the plan it to make both the board and the foil (using 3D printed skeleton). More on this soon ;-)

Thanks again for your input.



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"Inserts as an alternative to US box for foil mounts" started by Mokuleia