I just bought two secondhand AV boards Nuvolari. Both boards have oval, oversize, bolt holes that can accommodate 8 mm bolts (se attached photo). The "length" of those holes is 15 mm...!!
Surely this is not ideal? Won't ventilation become a big problem, and/or water getting pushed up through the holes, increasing drag? What is the best way to correct this? Suggestions very welcome..

I think the holes are longer than normal to cater for fins which are out of specification.
On mine, a larger issue was the box being about 0.5-1mm to long so fins sat too deep in the box. I had to cut a plastic shim from a takeaway food box to put down the front of the box.
Water does come up through the fin box, but no issues with air going the other way causing spinout.
Otherwise very happy with the board. Apart from the Goretex valve. Not required in the UK weather. Soon after getting the board I did the fastest 500m speed in choppy Poole Harbour for about 8 years or so.
I think the holes are longer than normal to cater for fins which are out of specification.
On mine, a larger issue was the box being about 0.5-1mm to long so fins sat too deep in the box. I had to cut a plastic shim from a takeaway food box to put down the front of the box.
Water does come up through the fin box, but no issues with air going the other way causing spinout.
Otherwise very happy with the board. Apart from the Goretex valve. Not required in the UK weather. Soon after getting the board I did the fastest 500m speed in choppy Poole Harbour for about 8 years or so.
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That's quite a bit a bit of water, but good to hear it won't be a problem. I might add some nylon insulators in order to reduce the water flow, something like this:
se.rs-online.com/web/p/screw-insulators/2326980
Another issue I found just now is that half of the footstrap screws, on both boards, were bent. I will replace all of them, but I am wondering if the screws are the correct type. Did your board come with this type of screws:
PS. I see you have the medium size, I have the two other sizes. Look forward to riding them!
I bought the board they used for Windsurf mag test so the straps were already screwed in place.
Ah, right. That was a glowing review.
its been used hard or crashed hard if they're bent like that. Often on waveboards, not so often on racey stuff. Have a goooood look at everything if they're bent
I just bought two secondhand AV boards Nuvolari. Both boards have oval, oversize, bolt holes that can accommodate 8 mm bolts (se attached photo). The "length" of those holes is 15 mm...!!
Surely this is not ideal? Won't ventilation become a big problem, and/or water getting pushed up through the holes, increasing drag? What is the best way to correct this? Suggestions very welcome..

Use rubber washer
If the fin fits properly it will seal any gaps.
Starboard supplied a couple of their oval serrated footstrap washers with a foil board, to be used inverted (smooth side down) on the foil bolts, which works well.
As stated above , probably slotted , because fins can be so far out. And because the holes are only 15 mm deep , they should handle way out fins.
Fin holes are most likely OEM and made for use with a foil
If you have a 3D printer or if you know someone with one you can drawup and insert which fits across the whole base of the hole and into the slot, and have it printed out of TPU which will seal it
its been used hard or crashed hard if they're bent like that. Often on waveboards, not so often on racey stuff. Have a goooood look at everything if they're bent
Yes, I was a bit worried but otherwise the boards seem just fine.
Fin holes are most likely OEM and made for use with a foil
If you have a 3D printer or if you know someone with one you can drawup and insert which fits across the whole base of the hole and into the slot, and have it printed out of TPU which will seal it
Good call, a friend of mine actually has a 3D printer. I'll talk to him.
Silly question, please tell me foil heads nuts have the same pitch as Tuttle? And is it true that foil bolts are quarter inch and fins are 6 mm ? Or is that early foils being imperial ?
Silly question, please tell me foil heads nuts have the same pitch as Tuttle? And is it true that foil bolts are quarter inch and fins are 6 mm ? Or is that early foils being imperial ?
Never found non metric in foil
I believe some foil bolts are M8.
They may also be slotted to allow for tilting of mast
Yeah, I was also thinking that. But I will be using fins only, going to find or make some oversize washers..
Silly question, please tell me foil heads nuts have the same pitch as Tuttle? And is it true that foil bolts are quarter inch and fins are 6 mm ? Or is that early foils being imperial ?
Never found non metric in foil
both my foils are metric
Silly question, please tell me foil heads nuts have the same pitch as Tuttle? And is it true that foil bolts are quarter inch and fins are 6 mm ? Or is that early foils being imperial ?
Never found non metric in foil
Had two that were. One built by a refugee to the US as a measure of pride in his adopted land and the other by a US shop that felt that users might find long metric SS difficult to find in the hinterlands (they aren't wrong but the internet solves that problem in a few days if you have the time).
Slingshot is the only significant outlier on M6 that Ive encountered with the original tuttle adapters taking M10 (M6 adapters were available) and the Phantasm jackplates (aluminum) taking M8. M8 is probably a better standard as there have been cases of M6s failing from stress resulting in a lost foil. But, most foil makers hesitate to try to squeeze it into the small space of the head and risking not having enough carbon fiber to keep it together.
For boards without a chimney for the tuttle screw, slotted holes can be helpful as when using a 90 or 100mm screw, alignment has to be at a high standard for everything to be straight. Or, the foil maker, like on the IQ can slot the tuttle head on the mast itself.
So, Imax1, rest easy. M6 will almost always do the trick. However, I have a quiver of screws from 45-100mm in length for various boxes and tail thicknesses ![]()
Ironically, my smallest board is the one that takes the longest screws.
Some foil masts have a true deep tuttle with the angled top and others have a "foil" deep tuttle with the top parallel to the bottom of the board. They drill the holes for the mounting screws perpendicular to the top of tuttle head so the screws are at different angles depending which type of deep tuttle it is. The slotted holes in the tuttle box allow for both. Just use a gasket washer when using with a fin.