Where or how should the downhaul be set when spin is up?

Downwind, release the downhaul to the "wrinkles just out" level.

Also, don't forget to rotate the mast 90 degrees, loosen outhaul, keep the main sheeted, travel out to about the footstraps if sailing uni or about half way to straps if sailing sloop(that's with the Taipan jib--blade jib is narrower)

I would disagree about the outhaul - I leave mine as it improves the airflow around the back of the sail. I don't believe you need a full main down wind as the apparent wind will always be forward.

I also disagree about mast rotation. Once out on the wire, again the apparant wind is forward so 90 is too far.

I'm just offering some starting points for Robi--obviously, conditions, sea state, mast wing section, trap/non-trap, wild/non-wild, spinnaker cut, spin sheeting point, etc, etc all play in. I find I that I really benefit from loosening the outhaul, not taking it all the way off, just to get the main a bit fuller. This is essential because in any wind over 10 knots I'm sailing upwind with my main set up very flat and streamline.

Bottom line is that every rig is a bit different, and different condition and boat speed can put the apparent wind further forward. Tell tails tell the tale of truth.

Of course I sail with the Superwing mast as well and with this mast you don't want to sail with less rotation than 90 degrees in strong winds. This mast is rather flexible in the top and has a low hound fitting. If you don't rotate it fully in strong winds than you can witness your mast bending forward by a huge amount. Been there, done that, with witnesses around and they assured me that I'd better do 90 degrees next time. Ask Phill Brander or Geert Ruesink; they were on the other boat waving and screaming for me to stop.

Of course in lighter conditions you can derotate (less rotation than 90 degrees) but when you do still keep a close eye on the top it doesn't take much load to bend the top away. The superwing mast section is simply different than most other catamaran masts.

On the outhaul I have no opinion as of yet. I haven't been able to experiment with that.

On downhaul; I loosen it as Eric says when I find the time to do it; halve the time however I forget to do and just sail downwind with it on. For some reason I haven't felt a clear advantage or disadvantage of either setting. Probably because when I forget to do it it is always blowing and so a flat sail may not be a bad thing then.

Wouter

So in essence, rotate mast more or less close to 90 degrees, loosen the downhaul a tad bit, keep one hull clear off the water, but NOT too high right?

The only thing that you absolutely must do is mast rotation, particularly with a wing mast. They are soft on the side axis so you have to rotate them or you will bust the rig.
Downhaul is pretty easy to sort, let it right off in lighter stuff and when is howling just make sure you let the tension go a bit so that you don't have the full upwind setting.
Outhaul is the easiest of them all: don't touch it. Ever. just set and forget. You could even tie it off and remove the cleat and pulley system.

I'm confused. 90 degrees sounds like WAY too much mast rotation for sailing downwind with spinnaker (unless maybe sailing straight downwind).

Robi,
The big thing to keep in mind is to keep the leeside junction between the mast and the sail as one fair curve. If over-rotated the mast will be a blunt obstacle (much a like fixed mast) for the wind and will not attach to the sail until much farther aft in the main. This is not good.
If under-rotated the union between the mast and sail will have a big indentation. The wind will come around the mast all happy and then bang its head against the rut. It will then bounce off and not attach again until way back.
The happy air molecule will come around the mast and pass over a very smooth transition between the mast and the sail.

It sounds like the advice so far is for sailing without a spinnaker. When sailing with main and jib you are going much slower and your apparent wind is pointing more at 90 degrees to the boat (that is the telltale on the sidestay points slightly aft of your mast.)
In that case you rotate your mast at 110-degrees and leave your main traveler out to near the hiking straps or maybe even farther.
That would be the ballpark setting to allow the smooth transition between mast and sail.

Now, with a spinnaker you will gain a lot more speed. And each sail backwinds the next, causing it to luff.
This is hard to explain, but here is how I read things.
I put a telltale on the bottom of the outer end of the pole (I use 8-track tape that is easy to find in yard sales, or go to Radio Shack and buy some cheap reel-to-reel tape.., same size), then I put telltales on either side of the forestay on the bridles, and finally on the sidestays.
Once dialed in the telltale indicating the apparent wind on the pole will be at about 90-degrees to the boat or pointing a little aft of that.
The telltales on the bridle will be flow farther aft by about 20 to 40 degrees.
And the telltales on the sidestays will be flowing amost straight back as if sailing on a close reach.

What is happening is the spinnaker is backwinding the jib. So, if you left the jib out it as at first set, it would be luffing.., so you sheet it in. Now it is sheeted in more than the spinnaker.., because it is backwinded.
Now, the spinnaker and the jib are also backwinding the mainsail. So, if you left the main out as at first set, it would luffing also.., because it is backwinded. So, you sheet it in.

So, with the two headsails both backwinding you will find the main is set almost as if it were on a close reach, rather than at 90-degrees to the true wind. That is because you are building tremendous apparent wind.

Back to the sail adjustments. Since you are now setting the main for a close reach, you only need to let your traveler down less than a foot, you probably do not have to even think about touching the mast rotation (it is probably set perfectly when you ease the mainsheet and traveler), don't mess with the outhaul, and you might ease the downhaul a bit.

Too bad you can't come to the Sailing Seminar next week. These are the basics we teach there.

And I could really get you tuned into your boat and save you years of experimentation. Just trade off some duty days with some other CooGoo. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" /> I used to be Hooligan's Navy.
Rick

Okay, let me get this straight. With most masts you would do as Rick has described, but if you have a superwing mast, you have to rotate to 90 degrees (an inefficient position for tacking downwind with spinnaker), so that the mast won't break?

WOW Rick! Thank you for the explanation. You are correct, IT sux that I cannot go to your sailing seminars. I would have loved to attend, too bad uncle sam got a good chunk of my money , wifes speeding ticket and a small run between the blade and a parked focus. all those added up to mucho mula!

I guess that is a true statement. The strong points of the wing mast when dead centered are fore and aft. In other words the longest section of the mast.

Maintaining what would appear to be a correct flow angle around the mast to the mainsail is of little concern when you are using a Kite. what really matters is keeping the mast in one piece. A wing mast such as superwing is more critical but even on the Tornado we rotate the mast to at least 90 deg when we go downhill particularly if we are on the wire. if you don't then you will have some seriously ugly bend.
Robi, I am not sure how windy you are planning on sailing with the kite but if you go out in 20kts you will bust the rig if you don't rotate the mast to at least 90 deg.

have a look at this pic: Taipan with kite

Or this: Tornado

and this: Nacra F18

Now all these pics are taken in light breeze, the only reason some masts are not rotated more is that there is not enough pressure on the main to force more rotation. You will find that the mast rotation control is loose allowing the mast to rotate as far as it wants.

Must agree with Macca here,
yes: the superwing mast is quite a soft and bendy mast
yes: it can stand up to a whole lot. The amount of bend and flick it can withstand in 25-30kts upwind is truly a remarkable sight.

But unless you rotate it, or any other mast to 90 degrees (ish) with a spinnaker up, you will eventually snap the thing in two - and cleaning up a rign that has fallen down with all the spinnaker lines etc attached is not a whole bunch of fun.

Sounds good and all, but after looking at the rigged mast. The mast cannot and will NOT rotate a full 90 degrees, maybe closer to 75 or even 80 degrees. The sidestays are limiting the mast to rotate the full 90 degrees.

Also another question. With the spinnaker flying will the load make the mast rotate to the mentioned 90 degrees? Or do I have to rotate it to its proper position? in other words, the Blades mast rotation control setup cannot make it rotate that far out. The Blades mast rotation system pulls the mast to the middle of tramp. Will the downwind load make it rotate to 90 degrees?

The mast will rotate to 90 degrees once there is load on the sail. Even with tight sidestays the mast will rotate and push its way into the stays.

Its almost impossible to get the rig tight enough so that the leeward sidestay stays tight upwind when everything is cranked on hard. Same rule applies with the kite up. Trust me, when you've got enough wind to fly a hull, you should have enough breeze to be able to rotate the mast to 90 degrees.

The wind pushing into the mainsail will be enough to rotate the mast. If not, just run in and give it a bit of a shove but the more wind, the easier it is, and the more likely it is to stay there.

With the kite flying, if there is plenty of breeze the mast should rotate and stay there, though sometimes if the loads come on at a different time out of a gybe (ie, kite loads up before mainsail) the mast might not rotate all the way around and only go to 70-80 degrees (you'll notice the difference if you look up!).
In really light breezes <5kts sometimes my mast won't rotate and stay there but you're not likely to break it in that stuff anyway.

Alright sounds good, Once I go out and test all the theory, I will post up.

Thanks for the good replies folks. I apreciate them all.