pivot offset?????

ok…
i just finished my Innovator (36/600) and I have way too much jib luff tension…worst after trying to setup the rig…I still cant really understand what I am doing…
so after reading this:
http://www.onemetre.net/Download/Jibstay/Jibstay.htm

I am even more confused…what can i do to decrease this jib luff tension? if i change the pivot offset will it help to decrease this tension?

Any ideas or suggestions…if you need pics i can send or post them!

Thanks for the help

Wis

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

dont forget about the jib topping lift, it’s settings can [:-hspin]also affect the jib luff tension

Wis,

Greg is right that if the backstay (and to a lesser degree the shroud) tension is the main thing causing jibstay tensiton. You want to use backstay tension to accomplish 3 things. First, to set the jibstay tension. Secondly, to set the jib topping lift tension, and third to bend the mast.

If you are increasing your backstay tension to keep enough tension in your topping lift to prevent it from snagging and this is causing too much tension in your jib luff, then you can fix this by moving your jib pivot back on the jib boom (and also on the deck). Think of the jib boom as a see-saw. If you move the pivot toward one end then you need a heavier kid (more tension) on that end to balance a lighter kid (less tension) at the other end. So if you have too much tension at one end and not enough at the other, then move the pivot to create a better balance…

but I also agree with Gregs quenstion of how you know you have too much luff tension. Jib sag will effect your pointing ability, so the only way to know if you have too much or too little is to assess your pointing ability relative to other boats of the same type or at least the same class. Have you been out racing your boat yet and noticed that you cannot point with the other boats?

  • Will

Will Gorgen

ok

As Greg told me before, i put the pivot @ 25%…

here some pics: (sorry for the quality)
<font color=“green”>Edit (dang i am stupid LOL…mea culpa)
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=3
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=4</font id=“green”>other thing…the rig was tested in a static situation…i didnt sail her yet…the ponds are still frozen and covered with snow.

This is really weird, with my Seawind I dont have this…i really have no idea why???
As for the topping lift…I wont use it!
Thanks

Wis

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

Where did you get the vang

you’ll get killed in light air without a topping lift

Greg,

I put the pivot @ exactly 25%!

I re rigged the whole thing and made all the changes you were suggesting, except the topping lift…boom is too short!
(Btw the toppinglift is for light air, right? I seldom sail in light air…why I said that I wont use one…anyway, if I use one, I need to change the boom!)
some new pics:
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=5
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=6
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=7
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=8
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=9
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=10
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=11

The jib luff tension is a LITTLE bit better…still bad (I think)…worst the gap between the jib and the mast is kind of tight.

Thanks for the help

Wis

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

Wis,

The toppinglift is not just for light air. In heavy air - especially puffy conditions - your jib slot will change drastically during the puffs and lulls if you do not have a toppinglift to control the leach tension.

Having said that, here is what I see in your pictures. The foot and leach of the sail are too tight (you can see the over-tension creases forming in each). This is because the back of the boom is pulling down on the sail as the front of the boom is being pulled up by the jibstay tension. The outhaul line then pulls down and back on the sail (due to it’s angle) causing the over-tension in both the foot and the leach.

You need a toppinglift! This will take the tension of the back of the boom pulling down (rather than your sail taking the load). Then, you need to tie a loop of line through the clew of the sail and around the boom to allow the outhaul to do its job (add only foot tension).

If you do not want to use a toppinglift, then you need to ease your backstay tension and very carefully control the backstay tesntion to get the jib slot (jib leach tension) you want for a given set of wind conditions. But either way, you need to still add the loop of line to hold the clew of the sail down to the boom.

  • Will

Will Gorgen

Will

Thanks for the advices…didnt know about the topping lift in puffy conditions…will be added right away…I ll give a try and let you know

Thanks

Wis

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

Greg, Will

I should be in bed… 0.40 am Friday 27th here…but I just had to try one more time to setup this rig…well good news…it looks much better…not perfect but better, BUT (Sorry no pics yet…late here),now the jib is touching the mast…I guess tomorrow I ll re-do everything again…oh and btw…what is “over-tension”…could you quantify this without using any measure instruments?

Anyway thanks for all the infos

Wis

(and now i am off to bed…tomorrow will be hard)

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

Wis
For a little bit easier adjustment I put an eye in the jib stay between the bowsie and the top of the sail. Then I moved the top of the jib uphaul to that eye. That way when you mess with the jib stay length you aren’t messing up the jib uphaul adjustment. Put the eye as high as you can to minimize the angle between the new jib stay eye an the grommet in the top of the sail.

Thanks
Don
Vancouver Island
I’ll see if I can add a Picture.

Download Attachment: DSCN2107.jpg
50.55KB

Wis,

“Over-tension creases” are the tendency for the sail material to fold over on itself along the direction of too much tension. You can also have over-bend creases if you bend your mast too much. THese are the things that greg pointed to with his circles in his previous post. By the way, Greg, is it still too cold to work in your shop? Nice job with the 8x10 color glossies with the circles and arrows. Do you have a paragraph on the back of each one as well (blatant Arlo Guthrie reference). Aparently you still have some time on your hands…

  • Will

Will Gorgen

Wis: I was wondering where you got the vang on the main sail

What excellence replies. Especailly Gregs with the marked up photos (1 picture is worth a thousand words)

I could be wrong here by putting this under this topic but it needs to be started.

It has started me to think (hard sometimes plenty of smoke and gears turning) that there should be a topic section ( under"Technology Discussions" or a new Subject say “Boat Setups”) for setting up boats, such as:
Standing rigging
Runniing rigging
Jib setups
Main setups
etc

Where members can write a descriptions and put photos of their setups up the subjects. This would allow poeple to compare, copy, change or totally rebuilt parts of the boats to a better system.

What do you think.

I will put this post in “General Discussions” so we won’t hijacked this topic as it is worth while maintaining the excellence discussions and pointers.

Looking forward to your responses under Boat Setups . See you there.

Hoj,

It looks to me like the “vang” is some sort of fixed geometry fitting.

If you are looking for compression vangs, check out this one sold by Great Basin:

http://www.gbmy.com/125.jpg

I know some others sell them as well…

  • Will

Will Gorgen

And here I am again…@ work LOL

Hoj;
The vang is a “fixed geometry” I cant adjust it…but the boom is attached to the mast with 2 ball bearings…I ll post some pics if you want.

Don;
Guess I am plain stupid…but I cant really understand your system…sorry.

Tonight I will post some new pics with the “better” setup

Again thanks to all!

Wis

PS: Greg; I have some carbon tubes from my old kites which I dont need…I guess I will make a jib boom from them.
As for the rig…first I will try to sail her like this…at least one time; then time to get a new rig…any suggestions here?
I know some guys sailing some Venoms and Orcos here in Japan…time to get more infos
http://www1.ocn.ne.jp/~try1/Center-05-BOATS.html its just about 450 km from my home…but I d love to sail with them

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm

Is there any reason,other than aesthetics(sp), to have the boom follow the shape of the sail?

Thanks
Don
Vancouver Island

Don,

You definitely do not want the boom to interfere with the jib freely tacking from side to side. Otherwise in light air you will have really bad sail shape. So the first requirement is to have some clearance between the jib and the boom.

Once you have done that, if you have a straight boom, then the tack and clew will be quite high off the boom which makes it hare to get good control over the foot shape. You want to hold the sail down to the boom at the clew so that you can adjust the shape of the sail with outhaul tension. If the clew line is at a large angle relative to the boom and is quite long, then it becomes very difficult to control the foot shape (draft). So the curved boom allows you to have much better control of the foot shape of the sail.

Of course the foot round for the US1M is free (unmeasured) sail area, so you want the foot of your sail to use the maximum round allowed by the US1M rules.

  • Will

PS - Greg, where are all the arrows and circles to annotate your picture? I expect more from you now that you have set the precedent… BTW, seems like your boom is a bit high (especially after some of our previous discussions).

Will Gorgen

Greg
Love the chequeboard paint job, hard to do???

Sorry should go in the new section under “Hulls”!!!

Ok, here I am again…
a few new pics…and it looks much better (I tried to adjust the same way Greg described on my SW…works fantastic…I ve never had such a beautifuly shaped rig

back to the pics:
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=12 (the whole thing)
http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=13 (jib)
and for hoj : http://groups.msn.com/wismerhell/shoebox.msnw?action=ShowPhoto&PhotoID=14

Thanks again, great job. Btw, Greg, keep on the work with the pics /comments…thats exactly what I need…very clear!
Wis

if it isn’t broken, don’t fix it!

http://wismerhell.esmartdesign.com/index.htm