jib luff tension

[Paul Gillard]

how does everyone get sufficient luff tension on the jib in fresh wind? not sure if class rules permit a cunningham at the foot, but really need some sort of purchase to get a good set

[Jay Harrell]

My boat has a halyard tension device that can be used to apply extra tension once the jib halyard is cleated off.  It's a multi-block purchase system with tails on both sides of the boat and I've never had any trouble getting as much as I wanted, although I usually don't need any more than I can pull on with the halyard itself.

[Paul Gillard]

Thanks Jay- does your purchase system run to the base of the tack (ie a floating tack)  or do you have a cunningham eye?
  I find in winds over 15knts(seems to be blowing in excess of that everytime I go out at the moment!) the halyard tension is too soft and it can not provide adequate purchase just going through the block in the mast.

[Justin Scott]

The standard "class legal" jib halyard set up has a halyard (cleated on the port deck) and  jib halyard fine tune which has tails run to port and stbd just where the deck meets the fwd tanks, within easy reach of the forward crew. The jib halyard fine tune is a "displacement" mechanism (You run the halyard through a bullet block attached to the fine tune which pulls the halyard and displaces it to increase tension), which has additional 4:1. This is enough to crank on jib luff tension in all conditions. I doubt you want to be bothered with a jib cunningham and have line running across the foredeck.

If you want to increase the purchase on the jib halyard fine tune, this would be a relatively easy thing to do.

Jealous of your 15 knots.......is it warm?       

[Paul Gillard]

Actually Justin - it has been more like 20-25+knots  besides the odd friday afternoon rum race(which are always fun) it hasn't been normal summer wind patterns at all. That's why my 1:1 purchase setup on the halyard hasn't quite been enough!!
  Regards, Paul

[Justin Scott]

Lucky sod.

1:1 doesn't cut it. We adjust jib halyard tension with the fine tune for chop or flat water even in 10-15.
You need to re-install the fine tune which must have been removed in one of Growler's previous lives. If someone has a photo of the fine tune mechanism perhaps they can post it (my boat is in Atlanta!)
After the halyard exits the mast, it goes thru a block attached to the hull on port side and then through the port deck. Between the block and the deck (or between the block and the mast), we run the halyard through a floating bullet block.The bullet block is attached to the fine tune line which has 4:1 purchase running up the underside of the foredeck and the tail splits to two cleats on either side of the boat accesible to the fwd crew. This fine tune "deflects" the halyard and has lots of purchase to increase or decrease jib halyard tension without coming off the rail. 

[Paul Gillard]

If anyone does have a photo would really appreciate it
Ta.
  Paul

[Jay Harrell]

Thanks Jay- does your purchase system run to the base of the tack (ie a floating tack)  or do you have a cunningham eye?
  I find in winds over 15knts(seems to be blowing in excess of that everytime I go out at the moment!) the halyard tension is too soft and it can not provide adequate purchase just going through the block in the mast.

Mine is just as Justin described - the tack is fixed and the adjustment puts tension on the halyard.  Here's the closest photo from the archives, but the fine tune is hiding in the darkness under the deck.  I'll try to snap a better shot this weekend.

[Paul Gillard]

Thats great Jay- my system obviously was removed at some stage-I do have a cunningham in one of my jibs, but it pulls the tack to one side down low so is not ideal, and not great with an extra sheet lying on the foredeck, but am getting a good idea of what you have got- if you do manage a photo of under the deck that would be great.
  Thanks for the help.
  Paul

[Jay Harrell]

Here's a photo of the jib halyard tension fine-tune from Bill Shaw's #17 Viper.  His is the only one I've seen with a Harken box - the others are using a multi-block purchase system with the same routing of the jib halyard from the mast to the fine tune block and then through a fairlead and up to the deck cleat.

Sorry for the shot quality - I didn't realize the foreground was out of focus in the on-camera preview!  But you can still see enough to get the idea.

[Paul Gillard]

Am about to put a system in my boat in next few weeks- Bill does the Harken box work fine- some say in certain circumstances it does not release that easily. i.e if conditions were variable and you wanted to ease tension it can be difficult. Have one lined up I can get but it would be good to hear if works ok in exactly the same application that i would be using it for.
Cheers

[Jay Harrell]

Specifically, Bill's magic box is located such that it tends to get in a bind - if it was somewhat further towards the bow it would probably be better.  And all magic boxes have so much friction that they don't release smoothly under light loads, but that doesn't seem to be a big problem on Bill's boat.  (Of course, Bill has sailed his boat more than I have - comments?)

[Justin Scott]

I think the standard system, using blocks works very well. U dont need the leverage of a magic box unless you are converting to a halyard/headstay (eg wire luff in the jib) and want to use the halyard to tighten rig tension. In the NE boats we use the halyard soley to tighten or ease the jib luff, and need the fine tune to ease easily to put crinkles in the luff of the jib. I never have a problem putting enough tension on the jib halyard, and at the same time it has little friction so even a light breeze is enough tension to ease the luff.

The course halyard goes thru one bullet block between the mast and its cleat. The bullet block is on the end of a line which has 4:1 (maybe 6:1, I would have to look inside my boat) and goes to two ends, one on either side of the boat. Tightening the fine tune pulls on the block and "deflects" the coarse halyard. Deflection gives plenty of power without much friction.   

[Greg Jackson]

Hey Tech Committee,

I'd like to verify that we don't need to run the jib fine tune as per the boat came from the factory?

This thread seems to say that with Magic Boxes and all.

Please let me know before I get a bunch of spectra nad a few more turning blocks!

Thanks

Greg
USA 46
heroin

[Robert Bernard]

Check out the Harken One Design layout page for the viper 640:

http://www.harken.com/OneDesign/Viper.php