No, I'm not talking about your Wife's undergarments, I'm wondering if there is any upwind, less drag, aerodynamic advantage to using a "lace up" the side type tramp, vs. the slide it into the hulls type.

The thought occured to me as I was going upwind on my old Prindle one day, in big wind. Now, my old Prindle tramp relly needs to be replaced, the side tabs that you tie into the hull slots are mostly pulled out, so about 6" of the sides of the tramp flap up in the air when I fly a hull and the wind gets under there...but it seemed as though it was much easier to control the boat's heal, as it did.

I started to wonder if maybe that's why the A cats (mostly) are using side lace ups? It allows the 'trapped' air pressure under the tramp a place to vent, which helps when the wind is up and you need to keep the hull only about 1' up? Or are they using them strictly to save a few oz. weight? Or something else?

OR...should we be designing our tramps to look like a wing laid on it's side, ie. fatter and round at the front beam (leading edge), with camber over the top, but flat on the bottom, tapered off to a thin trailing edge? Kind of like the Aka's on that 'flying' trimaran, Hydroptere? Do we want our tramps to help lift the boat, or no?

Seems the Curved Daggerboard school of thought says, lift the hull for less drag.

A tramp shaped like a wing would add lift too, right?

So, should we lace up, leaving an open slot on each side to allow the trapped pressure to escape, or use the lift to help get the hull up?
From my college Aero Engineering days, I remember that for any lift, there is also drag.

Without a wing shaped tramp, I think it's more drag than lift. But I'm going to have to get a new tramp for that old Prindle, I was thinking about a custom lace up vs. the same old thing.

I remember back when the I20 changed from the side slide to the lace up, but I thought that was due to isses of the slides pulling out of the hulls, more than any speed advantage. Did any of you who made the switch notice any improvements with the lace up?