Question:

Hello Jason,

Here come my latest insights, why I probably rigged the Bounce so poorly the first sessions. (It is a bit embarrassing, my apologies, haha.)

Well, the main question is, how do you measure luff length at Goya: From the end of the mast to the middle of the pulleys or from the end of the mast to the bottom of the extension?
I would say now, that it is the latter (and I hope I am right)…

With my former Gaastras, I have never had any problems with my standard Chinook RDM (old model with adjustment ring and pin) when I used the equivalent settings.
Without thinking, I rigged my Goyas the same way.
After another bad session two days ago, I measured the distance from the top of the ring to the bottom of the extension yesterday and I was floored how divergent the settings really are.

E.g., to rig the 4.7 Bounce with 406cm luff, I had chosen the 6 cm hole at the Chinook. In fact, this gives you a 410cm luff length.
Even worse with the 5.1. For obtaining a 419cm luff, I used the 20cm setting -> 23cm luff! With the 16cm setting, I get a real 19cm extension now.
To rig the 4.7, I will remove the ring the next time to get an zero base, as the block is 6cm.

Now I try and pull the pulleys of the sail as close as possible to the pulleys of the extension (as read in the Windsurfing Tricktionary book). Now I can trim exactly within 0,5cm accuracy and I can see the sail shape changing.

Well, lesson learned: With my rigging habits, the downhaul was way too high right from the beginning. I didn’t notice this because of the missing loose leech of the sail.
Especially when you start adding more and more downhaul to make the sail feel lighter, it made the sail nothing better but worse.

My explanation of this: With too much downhaul (that otherwise would have been visible but this is freestyle, haha), the mast was simply bent too much. That extra force met with the sail’s shape and pulled the two bottom battens even past the mast, as the construction of the sail is aiming at ducking. To counterbalance this I added either too little outhaul (super baggy sail) or too much (worst sail feel I ever had, haha).

Now the sail looks way better on land. Let’s see how it goes on the water.
I will keep you updated.

Best
Johannes

Answer:

Hi Johannes,

Luff length is measured from the tip of where the mast sits inside the sail to the bottom edge of the tack pulley.
Including the tip plug, most masts are about +1.5cm longer than what they say they are.

Boom length is measured from the front edge of the mast to the back edge of the clew ring.

An even bigger variation can be found on the assorted hardware on the market- in other words it says one extension amount, but the actual extension amount is something else entirely.

I see you are discovering that as well…. 😉

It’s OK, it’s an easy mistake to make…

It’s impossible to account for all these variations (and interpretations) across the industry,,, so my rigging method really relies on visual cues rather than numbers.

Bounce is a bit tougher because there is relatively less looseness in the leech of the sail as you rig it.

Interesting thing, is that Bounce, compared to the other designs, tends to work better with less downhaul overall,,, whereas I see you were ending up with more and more…

Try the Bounce with the leech just a bit loose between 1 and 2 battens,,, and with about 2cm of positive outhaul.
From there you can adjust the power and control of the sail with +1/-1cm of tension on both the outhaul and the downhaul…

Yes, please let me know how you go Johannes!!!

cheers

jason