I just noticed on a 2021 Tabou 91 race foilboard it is very thick for volume, and has a recessed mast track, but by just 40cm long by 15cm wide. The rest of the deck is the normal slightly domed shape. So when the rig is in the water the length of the tendon would keep the extension off the edge of the recessed part and the rail where the extension would hit is lower than the mast foot. So I think bunging a foilbox in a 'normal' windsurf board with a concave deck to sell more boards is a oversight.
think I came up with a way to protect the board deck, including areas already dented and flexible along the ridge. Will cover deck with the dual density eva padding AND then along the ridge will contact cement a 1-2" wide strip of 1/16" thick plastic to the eva, then any mast impacts will first hit plastic strip on top of the eva and dissipate the energy instead of possibly punching through to the board. Did something similar for my nose guard and it has worked great (1/16" thick plastic on top of 1/2" thick dense gym mat).
Select to expand quotePhilUK said..
I just noticed on a 2021 Tabou 91 race foilboard it is very thick for volume, and has a recessed mast track, but by just 40cm long by 15cm wide. The rest of the deck is the normal slightly domed shape. So when the rig is in the water the length of the tendon would keep the extension off the edge of the recessed part and the rail where the extension would hit is lower than the mast foot. So I think bunging a foilbox in a 'normal' windsurf board with a concave deck to sell more boards is a oversight.
interesting, well at least one manufactuer came up with a way to solve the problem in a wide foil board, the wider the board the bigger the problem, but the wide concave deck would still be a problem windsurfing, for me at least, since I use the same sails/mast/extension for windsurfing as foiling.
A problem I can see with plastic on top of the EVA is , it will be thick . When the sail is in the water it may raise the other side of the board up making things worse . Sail stuck to water , you leavering on other side = more crushing force .
If you don't want to fix the damage first , ( which you should ) , I would put a few layers of glass over the area . That way it's solid , flat , no tripping hazard and less ugly .
Select to expand quoteImax1 said..
A problem I can see with plastic on top of the EVA is , it will be thick . When the sail is in the water it may raise the other side of the board up making things worse . Sail stuck to water , you leavering on other side = more crushing force .
If you don't want to fix the damage first , ( which you should ) , I would put a few layers of glass over the area . That way it's solid , flat , no tripping hazard and less ugly .
good point Imax1, thanks. just the deck padding alone is 3/8" thick, mast can sink into that, but if I cover with 1/16" thick plastic mast will not. Will put on the padding and see how it works first. the flexible area is just so small and crack free, do not see the point of fixing it. If I just cover with glass, there will be no support underneath, and mast could then cause the glass to crack. The carbon deck is stiff but flexible, though once glued to the padding should be stable, will find out down the road.
Select to expand quotePhilUK said..
I'd say the cause is uphauling and the recessed mast track/higher rail. When standing on the board with the rig in the water because of the higher rail the mast is going to be resting on the deck at 1 point, which is where the dents look to be. Is your mastpad on the sail long enough to cover the mast at that point? The board is 80cm wide. The board is a light construction for freerace which is fair enough. When slalom/freerace boards came out with recessed decks it put me off them, as I had seen a few with dents there. Speaking to a slalom sailor, he said that in between heats he sometimes sits on the board with the rig in the water, rig sunk a bit. To help uphaul they sometimes stand on the rail to help lever the rig out of the water! The use larger sails than you (I guess you dont use 8.5m+) but I think it could still cause damage.
I would say boards which are uphauled a lot (beginner boards) dont have the recessed decks and dont think foil boards have recessed decks either. (Wow that lowered centre of gravity really does help control massively for the freeracer/freerider 
, not.)
I was going to buy a Bolt 125 when they came out, but stalled when I saw they had the recessed deck, earlier smaller Bolts hadn't. I nearly changed my mind but a decent older board came up secondhand.
If you can hear crunching when you press it, it is the carbon flexing, so needs fixing.
Hey PhilUK thanks, read your post (think I missed it in between my posts), you nailed the problem, appreciate your insight from first hand experience. I did use my 9.0 sail on the board on light wind foiling days back when I thought I needed it, now 8.0 is biggest sail. Sail mast pad is long enough and dense, just not wide enough to prevent damage, the pinch point is when the mast is at 90 degrees to the board lengthwise, then mast hits just the top of the ridge, 1" cross section. Do not want to open board up for some 1/2" x 1-3" long max spots that flex under firm pressure, will see how the padding works. Of course, will be hard to tell if it spreads under padding, until it is past the 9" wide x 24" long padding, one on each side of the mast track, but will check by pressing on the padding, dual density is pretty firm on the outside.
Here is the thing about repairing the dents first, the mast is going to hit the deck ridge in the same place and dent it again, probably even with the dual density padding covering the repair, so what is the point unless there is delamination?, which there is not.
Talked to another local shop about the issue of the mast hitting the top of the concave deck ridge. They also recommended repairing the dents and flexible spots, but I said the mast will just dent the repaired areas! To which they said, get a longer bolt for the mast base so the mast hits on a flatter deck area towards the rail. I measured and think I need a M8 bolt that is 1" longer, so would have to add 1" shim under the Streamlined mast tendon base. Deck area mast would then hit is not perfectly flat, but a lot better than hitting the sharp ridge. Would still add the deck padding. What do you all think about doing that?
found at Belmetric.com 100 mm fully threaded flat head allen drive M8. Not at boltdepot or McMaster Carr.
put pads on the deck to cover ridge dents and now have a 3/4" spacer for the mast base which makes mast hit on the downward slope of the deck past the ridge, all is good!
Select to expand quoteSandman1221 said..
put pads on the deck to cover ridge dents and now have a 3/4" spacer for the mast base which makes mast hit on the downward slope of the deck past the ridge, all is good!
You'll save the deck but kiss your toes goodbye
Select to expand quotechoco said..Sandman1221 said..
put pads on the deck to cover ridge dents and now have a 3/4" spacer for the mast base which makes mast hit on the downward slope of the deck past the ridge, all is good!
You'll save the deck but kiss your toes goodbye
Choco what do you mean about my toes? Had it out yesterday for 4 hrs worked great and toes are fine.
Select to expand quoteSandman1221 said..t3wind said..
Instead of the eva pad, would a shim under the mast foot be better or it's a dumb idea? You can get kitchen PVC cutting boards on various thicknesses
You need to check the length of the mast foot bolt to see how much it allows
thinking of something like that, they did something similar with the iQ foil boards to keep the extension collar from denting the board, put a carbon spacer between mast and extension collar to move collar lower.
Do you have any pictures of the IQfoil system? Would be interesting to see if it could be adapted to other applications.
