if you were looking at buying a new boat and it came in two configurations (uni and sloop). which would you buy and why? i for some reason seem to get this vibe that uni's are not as well received as sloops, but would that be part of you decision making process?
Assume it was a higher performance boat n20'ish. uni had a taller rig and sloop was a little shorter. sloop a little better at distance racing, but uni better around the cans. just a thought after seeing the m20 do well at the steeple chase. boat would be 20', 2-up with a spi.

Will, does your question assume that both configs are to be sailed 2-up?

Great, here comes the F16 crap. OH JOY!

yes,20', 2-up with spi, i fixed the original post to reflect that

oh yes, the "crap" from the "F16 rookies" and the "hijack" despite someone else bringing it up... yeah... makes sense <img src="http://www.catsailor.com/forums/images/graemlins/mad.gif" alt="" />
where did that come from...

We'll call it a "pre-emptive strike."

That depends on your overall purpose for the boat. Yes i am looking at a Blade. I wanted something I could race 2 up for when/if I find a female or light male crew, yet something I could also race uni then I wanted to and still be competitive. Also had to be 21 century technology. That is why I sold my Hobie 17 and bought the Mystere 4.3 to learn spin on. I think the Blade accomplishes this for me. I know nothing of the M-20, BUT can a boat that big be sailed uni and righted 1-up?

Doug

The M20 is pure boat sex! Get one if you can afford it. If I could I would!

let me clarify a little more. i'm not talking a/b sailing one up or any goofy class stuff like that. if you could get an m20 uni OR sloop, what would you get and why?

There is a reason the top M20 sailors have switched from uni to sloop, its faster that way.
I'm pretty sure that the M20 that won texel this year is the fastest beachcat around, and it has a jib.

Sloop

Ok then...
The F16 is the BEST boat around because it can do both and does it at less than 400lbs.

TREY STARTED IT!

I sailed the 18Ht (2-up UNI boat) for a while and it was very nice and simple. The problem, as someone stated, is it is not for distance racing because the jib really comes into play on reaches.

Or maybe just laid the bait . <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

yeah, I took it... I am just so sensitive, touchy, chip on shoulder, at least Fad didn't say it. Gonna rig up some "cow catchers" on the F31 to take nay-sayers out (too bad they will outrun me... then it will be my turn for a pre-emptive strike <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

This is why I love catsailor...you catch something everytime you go fishing.

Well, I think, having sailed tons of sloops, the 18ht and the CFR20 that both rigs have their merits. The uni's are faster around the cans, BUT I think the grove for those boats is much narrower (i.e. less forgiving). I think the sloops are more rounded in their performance, wider groved and obviously better for distance racing b/c of the jib for reaching.

Interesting that the polling is pretty much dead split, however.

It always suprises me that when every time a M20 does well in a race (not too often) that this is claimed to be the result of being an uni-rig while at the same time it is also about 150 lbs lighter then as good as all its competitors, 2 feet wider and at least 3 feet taller then its competitors. One would think that these differences make an impact as well, especially in light winds were a tall rig is many times more powered-up because of the laminair wind speed winds distribution with height. See the picture below.





Note how in laminair winds a boat with a 10 meter tall mast cat harvest 30% more energy then a 9 mtr tall rig. That is how much difference a single meter of mast length can make (in the extreme).


The only way to get a real answer on this question is to fit identical boats with these different rigs and compare them over a wide range of conditions. Actually that would require four different rigs as there four different ways how you equalize the uni-rig to a sloop rig in the important parameters.

-1- The uni-rig mainsail and mast are identical to the those of the sloop that in turn has an added jib. (Uni has less overall sail area)

-2- The uni-rig is identical in everything like the mast length but can move all area of the jib into its mainsail. (uni-rig has same sail area with same height and much more heeling moment)

-3- The uni-rig is identical in every like the mast length but with that amount of sail area added in its mainsail so that it has the same heeling moment as the sloop rig.

-4- The uni-rig adjusted both the mast length and sailarea to arrive at the same heeling moment as the sloop rig but now in the most efficient way performance wise.


Pretty much options -1- and -3- are slower then the sloop rig or at best just as fast in narrow speed grooves. Option -4- will not be much faster then option -3- at all, there is too little difference there. Option -2- will be faster in light winds (below 5 knots) but quite loose alot of speed when the winds turn turbulant (above 5 knots), it will loose more and more performance with increasing winds due to having significantly more heeling moment then the alternative sloop rig. Pointing will go out the door very quickly as well when the leech has to be slackened to depower the top of the sail.

Without a spinnaker all uni options are significantly less performant on downwind legs. This takes a large chunck out of their upwind advantage if it doesn't totally correct or overcorrect for it.

The only exceptions that can make unis more performant around a course is when the overall total amount of sail area is limited to a sufficiently low amount so that it is only practical to make one single sail out of it. Sloops really come into play when this limit is increased to a level where it is no longer practical to put all the area into a single sail.

That is the whole scientific founded story.

Wouter

Uni is NOT faster. If you are limited in sail area like the A class, it is more efficient to put it all in a single higher aspect sail. If you are not limited a jib adds more power at a low center of effort and provides a slot for smothing the flow. There is definitely a reason all the Euro guys have put jibs on their M20s because it is faster.

Uni is easier to set up as their is only 1 sail, but that is pretty much the only advantage. Personally I feel the uni is more difficult to sail, but that is primarily due to my lack of time on uni rigs. If cost and sail area are not an issue definitely go sloop.

Matt

Let me be the first to actually answer the whole question...

I would buy a sloop because my son and I sail together, we don't fly a spin so this is the most efficient sail plan (in my opinion) of the two options for our purpose.

Clayton