Jeff, can you do me a favor? I am re-fitting standing rig this year, and had thought of going to a similar configuration. My thought was to swage a ring, or pigtail on the port shroud. My boat is totally apart and I cannot measure the ideal placement of the ring on the shroud. Can you measure and let me know how high, as measured from the attachment point on the deck, to the location of the block as it is mounted on the shroud? I would be much in your debt for doing so. Rex

What is the purpose for pulling the board...less drag?
Thanks

Yup. It helps make the boat more slippery downwind. You still want enough board in that the boat mostly travels in a straight line (it's faster that way) and to ensure that you have enough bite in the water to fly a hull...but you're aren't too concerned about maintaining height since you're object is usually further downwind from your angle (so deeper is better). The boards present a good bit of drag - enough that you can feel the difference up vs. down...so up enough to maintain straight travel downwind but reduce drag.

Thanks Jake,

Is one side better than the other? Also, if the boards are drags, and to far down cause you to trip in other conditions, then why are they so long, and in some cases longer? Other than Mike's foils for lifting, can they be to long?
Thanks again

Forrest I-20

Deeper boards = more lift when going upwind, and will fly the hull quicker, so in light air, full down, and as the wind picks up and you don't need all that lift, you start to pull them up.

We lift both when possible - but the leeward board is more important...sometimes, if time doesn't present itself, we lift only the leeward board and get the other one on the next gybe.

It was blowing about 15 to 18 in those races. If you can see it in the video, we had our boards raised about 8 or 10" upwind too. The boat carries enough speed at those wind strengths that the boards are more effective and we didn't need all that board grip in the water...not only does it reduce the drag, but it helps to settle the boat down just a little by raising the center of lift and making the boat a little less tippy.

As to the perfect aspect ratio - I have no idea. Over the last 15 years, we've seen boards continue to get skinnier and longer. The latest F18 boards are over 6 feet long. The A-cat boards have also seen the same trend (until the last couple of years where the a-cat boards are all banana shaped). The trick is a compromise between slow speed handling (pre-start) and efficiency at speed. Longer narrower shapes (like an airplane glider) are better at producing efficient lift. Materials have mostly driven the aspect ratio of our foils - which is why we're seeing them become thinner and longer lately (more advanced use of carbon). I'm sure there's a point in there where high aspect ratio becomes a problem...but I can't image where that is.

How high up do your boards go with the up-fker? about half-way?

I like the system you describe (especially if someone besides the crew can do it, in case hoisting the spin takes more than 1/2 second), and the other suggestion about swaging a ring/block on the shroud with a purchase system under the tramp sounds very effective.

I believe they come up slightly short of half way (with the older, slightly shorter, infusion boards). The distance the line can go down into the trunk is limited by the depth of the hull...the line shouldn't protrude outside of the daggerboard trunk when the board is down all the way. This is really the limitation.

With the new Infusion Mk2 boards you have to hoist them with a block on the shrouds otherwise they wont come up far enough.

Rex,

I am in Singapore until March 3rd, so away from my boat. I can check with the Fiancee and see if she can pull the shrouds out to measure. Also, I am sailing the Thai Cat week in February, so I can try to measure there if someone has the same system.

The way the boat jets off when the spinnaker is set!Worth watching all day...