I am trying to find out if my spin will need to be cut down or if it can retain it's current size? I am trying to install a F18 spin on a Nacra 5.2. Red side of chute is 26'8", green side is right @ 23'. My mast is 27'8" tall and my spin pole is right @ 12' long. From my calculations the spin may fit but i dont know that it would fit properly? I have searched and searched and searched. I have picked up on the fact that you dont want the spin closer than 3' to the top of the mast. So will this chute work in its current form? Im not looking for blistering speed right now. Im more concerned with getting everything rigged properly and getting used to the launch/retreival, etc. If the spin needs to be cut i can always have that done but it would be great if it could be used.

You want our chute to have about a fist worth of slack in the leading edge when its flying, so take your hand and grab onto the sail and rotate you hand all the way to one side. Then take the measurement from the tack to the head with your fist still in the sail. Now measure that same amount from your pole end to the mast and where that spot lands is about the right spot for the bale. I wouldnt go more than 1/3 the distance above the hounds, so if the point on the mast where the spin would land is higher than that you can rake the mast back, or get a longer pole.

And cutting down a spin doesnt sound like it will work.

The key factor that you left out is how high the tip of the pole is above the mast step.

I went through this process a few months ago. You can rough-calculate this with trig, but there's a lot of variables that you won't know until you actually rig the boat.

My solution was to fake-rig the boat. Put a 12' pole on the boat - doesn't need to be a real spin pole, just something nice and straight. Make sure it's attached to the boat like the real pole will be, including pre-bend.

Then, with the mast up, actually measure the distance from where you want the spin tang to be to the tip of the spin pole. You can use a piece of line to do this. Use a fairly heavy piece of line (not kite string) as you'll need to put some tension on it to keep it straight and you don't want it to stretch too much.

For extra credit, if you also measure the distance from somewhere else on the mast (such as the hounds) to the pole tip, you can calculate the luff length for any tang position on the mast fairly easily using the law of cosines. That way you can figure out where the tang will need to be for a specific luff length.

I was assuming the pole was rigged, but thanks for making that clear.

And since he's already got the spin, I would move the spin tang and cut the pole before I went and changed the spin.

That's a good rough starting place.


My new Grant Piggot kite needs to have the luff as tight as possible when there is enough wind to wire (single handed) down wind; but in lighter wind, it needs a slacker luff to work.