Forestay/Jib adjustment

[Brian Mikiten]

I don't see much about forestay adjustments and given that there is no backstay, I'd expect to see more. I understand the effect of the shrouds on the tension but wondered if there was a standard (or typical) length of the adjustment loop at the clam cleat by the furler attachment. I seem to have only about 3" of adjustment but remember seeing boats with over 12". Assume no vang is on.

THX

[Dean Nelson]

The length of the forestay determines the mast rake.  Per class rule 7.4. "The length of the headstay assembly is optional. The recommended total length should be so
that the rake of the mast (dimension R in Figure 3) is between 34′ 9″ and 35′. This measurement will not be enforced and has been kept in the rules as a reference point only."

[Brian Mikiten]

Good guidance. I'll check the measurements.

[Josh Jones]

So now that a lot of people are installing adjustable forestays, and this is no longer "enforced", what length are folks using?  Are we really adjusting the forestay regularly based on conditions?

[Brian Mikiten]

In my case, I had to replace some of the components in the adjustment cleat mechanism and was concerned that I didn't provide enough adjustment. I had seen some boats with almost 12" of available line even if they only used 3-5" of actual adjustment. I realized this was an issue when during the last race we were being very out-pointed by another boat and saw that my jib was quite loose (floppy forestay) and beyond adjustment. I can't imagine doing any on-the fly adjustments but this would be for basic set up and tuning.

[Josh Jones]

hmm, I never thought to consider that as an indicator of rake measurement

I suppose it would be relevant if all of our jib haulyards were calibrated at the exact same distance, but I'm not sure that is the case

[Brian Mikiten]

To further my education (obsession) on this subject, I pulled my jib (furled) and found that I had about 3" of adjustment on the headstay. This compares to what looks like 12"+ in the original manual. I'm going to confirm that my mast is not WAY forward tomorrow but wondered what other people had for available adjustment. Photo from the manual is shown here.

[Dean Nelson]

How tight the jib halyard block and tackle assembly is adjusted has secondary/minimal effect on the mast rake.  The length of the block and tackle assembly is simply dependent on the length of the jib halyard.  How tight you want to pull the jib halyard block and tackle is dependent on the wind strength, whether you want any wrinkles in the jib luff and how much curvature you want in the jib luff.  Pulling the block and tackle assembly tight results in the belly of the jib moving toward the luff, reduces the wrinkles in the jib luff and reduces the curvature in the jib luff...all resulting in depowering the jib.  Having the block and tackle assembly too loose results in wrinkles at the luff, the belly moved back and more curvature in the jib luff.  Experience will tell you where the proper jib halyard tension settings are for low, medium and high wind.  Mast rake can primarily be adjusted via: 1) the length of a fixed forestay, 2) the length of the upper furler pigtail, or 3) an adjustable forestay.  Recommended mast rake is between 34'9" and 35'.  On windy days, typically less mast rake is desired.  On low to moderate wind days, typically more mast rake is desired.  Mast rake cannot be adjusted out on the water.