Dave:

Your question can be taken a couple of ways. Are you asking the physical way they work or whether the catamaran performs better with them?

As to whether they work better. I am kind of surprised that they are on the Infusion. When Pete and I took the boat out with both set ups there was no real obvious performance difference. He was thinking of scrapping the idea. That was only tested one day though. He has since gone back to the drawing board and decided that on paper it will be worth it. The last time the boat was sailed, actually hull #1, everyone on the boat liked the way it sailed. They got the balance on the helm exactly right, it was agreed. The new standing rigging is really nice. The sail is going to get just one more iteration, making it a bit fuller.

If you are sailing the Gybing boards you will have to pull them up downwind. They apparently can get out of sync. I think that 1/2 way is fine.

As for physically ("how they work") in case that was your question. Imagine that the dagger well is bigger that the board. That makes a kind of a sloppy fit, so bind the back of the board to stay in place. That leaves the front to move back and forth. The pressure of the wind is pushing the boat against the water and turning the boards to lock the leading edge a bit into the direction of the wind. It is not very much. They are designed for better performance going to weather. Maybe they should be called tacking daggerboards? If you own the boat and do not like them Gybing it is just a matter of filling in the gap.

Later,
Dan