26M Forestay Sag

[baldbaby2000]

We just got back from sailing on Lake Granby this weekend. Winds were anywhere from 0 to gusts of 30 knots. Lots of convective storm activity. We started out with the genoa (roller furler type) and full main. When the gusts hit and the boat was severely overpowered I was spilling air with the main sheet. I observed that whenever I had to do this the forestay sag would increase quite a bit. I can see where the lack of the backstay on an M would exagerate this effect. The proper forestay tension and mast bend rely on the force of the main on the mast and when the main is released this force is reduced. From what I've read a sagging forestay gives the genoa more shape; probably not what you want during gusts. I don't remember how tight my vang was but maybe a tight vang would help. I also wonder if the sails supplied for the M have an optimal cut for this type of rig.

I'll probably try tightening the upper shrouds and this should help some. I guess the best thing to do is to reef before hand. The downside is that when the wind does let up you'll want to take the reef out.

My questions for you M and X sailors are:

How much forestay sag do you think is OK?

How do you deal with variable gusty winds?

Thanks for any advice.

BB

[richandlori]

From the moment I got my boat, I was always concerned about the "looseness" in my rooler furler. Even while sitting in drydock, it looks like it is loose and could use some tightening. Does anyone else see or have this impression?

Rich

[baldbaby2000]

In my CDI instructions it says that the halyard itself doesn't need much tension; about 50 lbs. Thus, the tension must come from the forestay. I believe my upper shroud tension is around 100 lbs. I may try increasing that.

[Richard Lisch]

Your shroud tensions on the M should be around 200lb. for lower and 250lb. for upper shrouds.

[baldbaby2000]

Your shroud tensions on the M should be around 200lb. for lower and 250lb. for upper shrouds.

I assume yours are that tight. Do you have any mast rotation problems?

[Richard Lisch]

No mast rotation problems at all, also have main halyard and single line reef led back to the cockpit.
Your minimum tension on the M should be no less than 180lb on lower and 200lb on upper shrouds.

[baldbaby2000]

Thanks Richard. I'll give it a try next time I'm on the boat.

[dgsl]

I am also concerned about stay tensions. How is anyone measuring or quantifying tension?

Darrell

[richandlori]

exactly my question Darrell. I assume with some type of tension measuring device? Does anyone have any recommendations on such a device?

Rich

[Frank C]

You want a Loos Gauge.

The correct size is $62 at Online Marine. I recall mine was only about $45 a couple of years ago, but it reads to an index scale (not directly in pounds of tension) so maybe that's a reason that mine was less costly.

[KaiSchuler]

If checked out the website of this "Loos Gauge", and am not sure I understand how it works. Apparently, it is attached to the shroud, and measures some kind of deflection. I would assume, that the amount of deflection depends greatly on the overall length of the shroud. Any comments from people who have used the device?

Thanks!


Kai

[Richard Lisch]

It's a spring loaded device, very simple to use and shroud length doesn't alter the readings. Mine is from West Marine. Make sure that you buy it for the right shroud diameter.

[Moe]

You want the one that does 3/32", 1/8", and 5/32" diameter shrouds.

--
Moe

[richandlori]

So lets say I buy the devise to measure the tension, now with the stay adjusters instead of turnbuckels, what is the +/- of the adjustment I can make? IE: is one bolt slot on the stay adjuster 20lbs or 40lbs?

Rich

[Andy26M]

Rich -

You'll actually find the adjustments available on the verniers for the shrouds to be very fine - the shrouds are probably able to be adjusted finer than the basic Loos guage measures.

The thing to watch, however, is whether or not you can still pin the forestay to the bow once you have the shrouds tensioned...

I have 240# on my upper shrouds atm, and it is all I can do with my 210# body to get my forestay pinned (with the genoa rolled on the furler; if I take the genny off it is a lot easier, of course).

AndyS