I have a board that can't seem to hold the mast base in a fixed position. Even if tightened to the limits of my strength it isn't guaranteed to stay where I set it, but it's also a bit random, sometimes staying put despite multiple crashes during a session on the water, sometimes sliding forward to the front of the track after only a couple.
It happens with either of my mast bases, but both bases stay fixed on my other boards.
Someone at the beach suggested that the deck needs regripping, but I don't think so. The area around the mast track is as rough as sandpaper.
I'm wondering if it might be a deck flex issue, so the loss of traction isn't on the deck itself, but between the nut and the track inside the board.
Any suggestions for a way to fix it?

Try getting the surface of the t-nut that contacts the track and hit it with a centrepunch a few times. Now its rough.

If that works, there are foil t-nuts that are rough and have a larger surface area.

If it still slips I'd be surprised but at least then you can investigate other causes like it slowly undoing (?) but putting goop on the bolt to stop that might be a big hassle

Does board have alot of dome.

Check the bolt is no longer than the depth of the mast box.

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Mark _australia said..
Try getting the surface of the t-nut that contacts the track and hit it with a centrepunch a few times. Now its rough.

If that works, there are foil t-nuts that are rough and have a larger surface area.

If it still slips I'd be surprised but at least then you can investigate other causes like it slowly undoing (?) but putting goop on the bolt to stop that might be a big hassle

Are you saying there are nuts that are longer along the mast track to provide more friction? Where do I get one?
That said, I just looked at the nuts on my foil mast. They are larger, but they are a different bolt size

What brand of mast base?

I've had the internal bolt unscrew itself on one model, causing some issues. And lmax may be right about the bolt being too long too.

The bolts are fine, about 2mm internal clearance.
1 base is NP, the other is Severne. Both are happy to stay seated in Starboard and Naish boards, but not this JP Magic Ride

I've had problems with bases that have off set bolts, they can unscrew slightly and move forward. (crazy idea really, why would you make one like that?).
But you'res probably isn't one of those.

You could also try the Chinook two bolt mast base.

Probably nothing to do with the issue in this case, but Im not a fan of the old t nut. Too many times i do it up and find its not seated properly and disengaged then slipped half way through a session.

The latest base from Severne has neoprene on the disc towards the board, this works much better than the traditional hard plastic disc only.

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SurferKris said..
The latest base from Severne has neoprene on the disc towards the board, this works much better than the traditional hard plastic disc only.

This. Add some rubber

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Mr Milk said..
Are you saying there are nuts that are longer along the mast track to provide more friction? Where do I get one?
That said, I just looked at the nuts on my foil mast. They are larger, but they are a different bolt size

Yes there is and they have grooves across them for more grip ... I'll have to see if M6 or M8 ..... prob the latter

In reality, the cratering caused by a centrepunch would have more bite than the ridges on the t-nuts.

I thought of a simple fix without requiring a lot of work sourcing bits and pieces.
Just block the mast track ahead of where I want the mast base to sit.
I reckon an old toothbrush handle or 3 cut to the right lengths will be about the right size to slip into the track to stop the base moving forward