I've always heard (and experienced) that the uni rigs tend to outpoint the sloops - no?

The jib acts as a slat acts on an airplane wing, pre-bending the airflow around the leading edge allowing the wing to operate at more angles of attack without the flow seperating. Most texts on sailing list this as a major advantage of the sloop over the una.

Jimbo

Uni rigs point higher, period. An A-cat can point higher than anything on the planet.

On a Hobie 17, I've beaten I-20's to weather in flat water and 15 kts+. Pointing higher, going faster.

Slats (jibs) allow a higher angle of attack without stalling. They do not facilitate a low angle of attack (pointing higher).

It seems to work for both lower and higher AOA's. There's some interesting discussions in the archives of the boatdesign.net forums on just why this might be so. The gist of the arguments seems to come down to the headsial's finer entry or leading edge. The mast is the LE of an una. The blunt LE of the mast allows the stagnation point to slip over to leeward at low AOA more than the fine, sharp LE of a headsail. So then the mainsail is actually operating at a higher AOA and making much more power. Seems to make sense.

I don't argue about the performance of the A cat; I'm sure it is all so many people say it is.

My sole experience with unas was with my first cat, a Hobie 14. I added a jib after a while and found it did point noticeably higher.

Jimbo

Sailing my H17 in mixed fleets I have always counted on the fact that comming out of the gate I could point higher and work up into clear air above the sloops. Works every time.

BTW. Matt...When you sail a 17 do you adjust your mast rake for different wind strengths?

I never adjusted the mast rake on my 17 in 10 years. Found a good spot and left it there. I carried a looser rig than most people, though. Allowed it to flop forward a bit going downwind.

On the photo below, look at how loose my leeward shoud is:


I was already prepping to round through the gate in that photo, so it's not *really* sailing downwind. The traveller is almost up to center.