Actually Macca, I'm curious too. I have the same problem of boards (and rudders which are also sliding up and down in a cassette on my boat) not staying in position and ridding up as I sail. Until now I've been adding slimmed down carpet in my daggerboard wells (and rudder cassettes) to add more drag so the damn things stay where I put them. And replacing them every season.

So I'm thinking I'm missing something in the picture if you say you put teflon tape, as this is going to lower drag. The only way I can imagine this working is if the teflon compresses the board in place: aka it should be fairly hard to engage the daggerboard? How much clearance is there between the well and the daggerboard? How much of this clearance to you fill with teflon tape? Do you taper the teflon?

To answer the original questions:

- Plastic spacers: I only have one at the top and one at the bottom on each side, but my boat is equipped with the old style 49er rudders, without winglets.

- Slimmed down carpet.

- No idea, I would have to measure mine