A possible different way of preventing a fan-up.

In response to my previous posting, Linda expressed concerns to me about complexity and friction from my FUP on China Moon's double rig.

Here is a possible other way of doing it:

• ·         Add a pair of long ‘yard parrels’, going from the throat of the yard and to the shown point B1.  The parrels are to run outside the topping lift and mast lift.
• ·         The position of B1 must be as far forward as possible, but not so that the parrels jam against the topping lift in normal use.
• ·         These long parrels should be just slack enough to avoid rubbing hard on the topping lifts during sailing.

These parrels will prevent the yard from flying forward of the topping lifts in case of a long, wild gybe.
However: The topping lifts themselves must be kept half-taut to act as a groove for the yard and battens to stay in, even with a slack sheet and in rolling sea.

For that reason, I recommend rigging the tackline more like a kicking strap, as on the diagram. That is exactly how I make the tacklines on my sails, in combination with my FUP. Keeping the boom from flying (much) up is important in any case.

I also drew up these long parrels for the two upper battens as well, but now I don’t think they are really needed. If the battens are lengthened slightly, there is no way they can fan up past the yard.

Just as with the ordinary FUP, one can try out this version in the harbour by over-peaking the yard with the yard hauling parrel, YHP.

Worth trying, me thinks.

Arne

(See Arne's sketches, section 8)

Linda,

there is a simple method to test the fan-up preventer  FUP.
On the photo, Ingeborg’s sail is setting four out of seven panels. With only three panels up, the peak of the yard is nearing the boom lift, so risks falling forward of it. The yard extension stick was made to prevent that. Then I added the FUP, as per that article, above.

To verify that it works, I did this:

First, with the FUP line not made fast, I could easily haul on the yard-hauling parrel, YHP and the yard would then be peaked up until it would fall forward of the boom lift. That would actually be a slow motion fan-up.

Then I repeated the exercise, but this time with the FUP line tied half-taut. Hauling on YHP would then not be able to peak up the yard. Both the furled bundle, plus the boom would have to be lifted. Even more, the slightly beefed up boom is held down by a tack line, which is rigged more like a kicking strap with a rubber snubber on it. With this at work, there is no way the boom will swing up. Therefore, that FUP is good.

If you can lock the yard and top section from fanning up on flat water, then a fan-up is unlikely to happen offshore as well.

Friction
Make sure you use a slippery FUP line, say 5mm flag line, and pass this through low-friction thimbles or blocks  -  and run the line on the outside of the lazyjacks.

Good luck,
Arne

FUP-line working on batten 2.