Fair enough .... no keel.

There is a boat like that in the US with a keel.

Rick

Very weird looking mainsheet set-up, can't quite work it out, looks as if you sheet from the bottom of the mast. 

http://www.vaxxine.com/clsailboats/stealth/develop/images/stealth%20002_jpg.jpg">

looks way too easy to pitch pole to me!

Re the unstayed mast comment before...

Is it just the angle, or does the rig seriously invert with assymetric up?

I suspect it's sailed on the great lakes where there is not much wind.

Can you imagine that in 25 knots at Lymn Regis ... dive, dive dive ...

The boat looking simular with a keel http://www.sailabongo.com/m/_general/bongo_photos.asp - http://www.sailabongo.com/m/_general/bongo_photos.asp

Another disaster in the making, pitchpole it self rights and sails off

Unless you're close reaching, in which case it powers you up...

Could be entertaining!

If the kite lifts the boat and the Center of Gravity is behind the point of lift then that will effectivly lift the bow

wether the kite lifts the bow all depends on the ratio between the length of the mast and horizontal distance between the mast and the end of the pole. The shape of the kite and the position of the kite sheet reletive to the CofG also makes a difference.

I Wouldnt Touch that thing,
1; it looks either expensive ( breakages of masts and the mast step and reinforcing around it)

2; looks boring unless you get into a descent breeze and then you can reference point one.

JimC you said that

I was responding saying that they can it is not common but they can lift the bow.

As you said the center of effort in the kite is about 10 feet in the air but what direction is it in? there are three components forward, up and sideways and the relationship depends on the shape of the spiniker.

Ignoring the sideways component these forces can be resolved into acting on three points

The haliard exit point approx horizontal
The tip of the pole approx vertical
The sheet turning block approx 45 degrees

These forces act on the boat through the lever arm of their attachment point and can be reduced to a force vector acting from approx the base of the mast in a forward and upward direction the magnitude of each part is dependent on the shape of the kite and the length of the mast and pole.
In the majority of boats the forward part far outweighs the upward part thus pushing the bow down, however if you have a very short mast and a very long pole then the resultant force has a large upward component.

The center of drag is located at or below the water line but also at the aft 20% of the boat and acts in a backward direction.

So you have a large back force acting against a large forward force  with a small upward component in a torque couple lifting the bow.

Have a look at some of the video of 12foot skiffs in windy wether when they have short masts and long poles and you will see this effect.

12ft skiffs dont have short masts, they are 30ft long from the keel, compare that to an actual waterline length of 12 foot, that rather large.
I hope in your viewing of the 12 ft videos you notice that the skipper and crew are right down the back of the boat? Maybe that mass creates a moment around the center of effort?  its not all kite that dose everything!

The No1 rig may be 30 foot but I would imagine the No 4 rig is slightly shorter The poles may also be shorter but probably not to the same extent.

I am not saying the lift from the kite is huge but I think that there is some lifting effect.

The difference between a windy white sail reach and one with the kite up is significant in where you need to be in the boat and how much the bow goes down.

to me that says that the center of effort in the rig has moved and that movement is pushing the bow down less than without the kite.

12 ft skiff masts - lets not argue big fish here.

From C-tech website:

	No. 1 Prod	(up to 3.6 meters; 5 spreaders)
	No. 2 Prod	(up to 3.0 meters; 3 spreaders)
	No. 3 Prod	(up to 2.5 meters; 3 spreaders)

By my reckoning to changes in length are pretty much proportional so the angles don't change much.

From all the 12ft skiff video clips I have watched it seems that as the kite is sheeted on, the boat accelerates and the bow goes down.  The bow then bounces up off a wave.  Once the bow is up at 30 degrees to the horizontal and the transom is dropping out the front of the wave, the back end goes down and the bow stays up.

So it would appear to me that - when the boat is trimmed approximately level fore and aft, then the kite pulls the bow forward and down.  Once you hit a wave and the bow points skywards, all the force vectors change and then the kite can be perfectly capable of lifting the boat into the air!

I think Mr. Redback may have a very valid point though - when you are two sail reaching the drive is coming from the main and jib - very much forwards with little in the upward direction.  Once the kite is up and driving, the force from the main and jib is greatly diminished so for the same heeling force, you get greater forward drive but also a greater lift at the front of the boat. 

Based on this, I think you could conclude that the kite normally drives the bow down - but to a lesser extent than when sailing under main and jib alone.  The kite is capable of lifting the boat when the boat is trimmed massively bow up.

From my time SAILING 12ft skiffs, when you are hit with a gust you bare away and go with it, the bow dosent get dragged up or down.  This is on flat water tho.  When on the harbour there are, wait for it waves!!! and funnily enough they have the tendency to make the boats hobby horse (leap out of the water).  Thats right, being only 12 feet long even small waves mave a big impact on the stability fore aft.  The sails are only half the component of all the force vectors involved.  You guys are neglecting the other half, the boat and the live ballast that is aboard it.  Its not having big rigs that makes 12's great boats, its the guys sailing them!

I agree I thought arguments raging for days based on false logic and wild statements were the whole point of forums like this?