Luff groove furler

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Quoddy

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Apr 1, 2009
241
Hunter 260 Maine
Jib halyard tension affects the draft position and groove width. On the CDI furler, which has an extrusion with luff groove, they say to tighten the halyard till the wrinkles are just out. They seem to ignore any question of high or low tension. Does the solid extrusion have some special effect on the jib luff and draft position?
 
Mar 26, 2011
3,976
Corsair F-24 MK I Deale, MD
Yes, it certainly does have an effect. However, I think they may be concerned about the effect of a continuous load on the furler bearings. The greater the luff tension, the greater the commpression, and in some cases, the greater the difficulty furling.

Plus replacing the bearings is a bit of work, but is something that needs done ocationally.
http://sail-delmarva.blogspot.com/2009/09/hood-seafurl-800-bearing-replacement.html
Certainly your model is different, but this should give some idea.

When I had hank-on sails or just a foil, I would adjust. With the furler I do not.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
I think you mean luft sag not draft position. A loose footed (all jibs I know) does not really have (or need) draft position controls as that is all done with the sheet and sheet controls. Course luft sag is controled by the forestay tension not the halyard so perhaps I'm missunderstanding what the issue is.
 
Oct 2, 2006
1,517
Jboat J24 commack
The jib shape just like the main is affected by haylard tenision/wind strenth
 

Joe

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Jun 1, 2004
8,323
Catalina 27 Mission Bay, San Diego
Quoddy.... Is your CDI the type with the halyard built into the extrusion that would be difficult to adjust under way? If so, the instructions are simply suggesting a neutral position that will allow the furler to operate satisfactorily.

If the halyard is external, i.e. attached to a swivel at the head, and you can adjust the tension underway, then the trim adjustment features of the halyard should be the same as a hank on rig or a racing foil set up.
 
Last edited:
Jul 1, 2004
567
Hunter 40 St. Petersburg
Nope, he means draft position.

I think you mean luft sag not draft position. A loose footed (all jibs I know) does not really have (or need) draft position controls as that is all done with the sheet and sheet controls. Course luft sag is controled by the forestay tension not the halyard so perhaps I'm missunderstanding what the issue is.
(I think.) Hi Bill. Headstay tension will mostly control luff (not luft) sag. This'll also be affected by backstay tension if he has one. It'll change draft somewhat.

Halyard tension will change his draft position as Tommays says. With enough of it it'll also help with headstay sag but he probably doesn't want the blocks, bearings, shackles, etc. that loaded up.
 
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