tension adjustment with new standing rigging

[paul I]

So I replaced all the standing rigging on my 2000 this year. All new stays are from BWY. When I installed them I removed the mast from the boat with all the old stays attached and laid then out against the new ones using a side by side measure and replace routine. I adjusted the new veneers as needed to get to the right length'. When I did the forestay I measured the free length of wire coming out of the furler end cap while the foil was laying flat and reasonably taunt (6 1/8") and duplicated that length with a turnbuckle adjustment after replacing the head stay. I needed to close the turnbuckle considerably due to 1.5" or so difference in length between the old one and the new one. I thought this would be a good starting point for tuning. I estimate the new stays are within 1/8" or so of the length of the old ones.

I raised the mast for the first time in my yard to do some tuning. The pic shows the mast profile. It looks more bowed in the than I remember. I verified the 94 degree mast rake angle and it is close enough at about 93.5.



Loos gage measurements for the uppers are 29/30 where 30=350 lbs. Lowers are off the low end of the scale, apparently below 150 lbs or so, and they feel significantly less tight.

Am I correct in the thought that easing tension on the uppers will apply more tension to the lowers and remove some of that bend?

Any discussion is welcome.

[dlandersson]

That would be my thinking

So I replaced all the standing rigging on my 2000 this year. All new stays are from BWY. When I installed them I removed the mast from the boat with all the old stays attached and laid then out against the new ones using a side by side measure and replace routine. I adjusted the new veneers as needed to get to the right length'. When I did the forestay I measured the free length of wire coming out of the furler end cap while the foil was laying flat and reasonably taunt (6 1/8") and duplicated that length with a turnbuckle adjustment after replacing the head stay. I needed to close the turnbuckle considerably due to 1.5" or so difference in length between the old one and the new one. I thought this would be a good starting point for tuning. I estimate the new stays are within 1/8" or so of the length of the old ones.

I raised the mast for the first time in my yard to do some tuning. The pic shows the mast profile. It looks more bowed in the than I remember. I verified the 94 degree mast rake angle and it is close enough at about 93.5.



Loos gage measurements for the uppers are 29/30 where 30=350 lbs. Lowers are off the low end of the scale, apparently below 150 lbs or so, and they feel significantly less tight.

Am I correct in the thought that easing tension on the uppers will apply more tension to the lowers and remove some of that bend?

Any discussion is welcome.

[sailboatmike]

Looks pretty good to me, the prebend isnt a issue.

But how did you measure the mast rake? Looks very straight to me taking into account the boat deck is not parallel to the ground

[Tomfoolery]

The manual says 4 degrees of rake, referenced to the flat area of the deck immediately in front of the mast. It also says the mast should have about 3" of prebend, which can be checked with the halyard pull tight to the mast at the bottom (should already be very close at the top).

I would increase the tension on the lowers a bit and check again. Increasing lower stay tension will increase the upper stay tension, so you may have to back off on the forestay a little. A little more of this, a little less of that . . .

Oh, and my Loos gauge measures about 300 lb on 5/32" rope when the needle is on 30. I checked it using olympic plates and a shop crane, for calibration purposes. There's a thread on here somewhere about that.

[paul I]

Looks pretty good to me, the prebend isnt a issue.

But how did you measure the mast rake? Looks very straight to me taking into account the boat deck is not parallel to the ground

Again I think there is too much bow, centered right in the spreader area. No?

For rake I cut a 1x6 about 18" long to a 94 degree angle in a chop saw that I trust. I set it in line with the mast step and adjusted to it. I was only off by a small amount based on the overall length of the old head stay.

The boat may not be at the proper level based on a waterline, but the trailer frame IS level.

[paul I]

The manual says 4 degrees of rake, referenced to the flat area of the deck immediately in front of the mast. It also says the mast should have about 3" of prebend, which can be checked with the halyard pull tight to the mast at the bottom (should already be very close at the top).

I would increase the tension on the lowers a bit and check again. Increasing lower stay tension will increase the upper stay tension, so you may have to back off on the forestay a little. A little more of this, a little less of that . . .

Oh, and my Loos gauge measures about 300 lb on 5/32" rope when the needle is on 30. I checked it using olympic plates and a shop crane, for calibration purposes. There's a thread on here somewhere about that.

Yeah I read your post on the gauge. Interesting. A 15% difference right?

But don't I want to relieve some tension on the uppers to help smooth out the bow, then possibly add tension on the lowers if needed?

[dlandersson]

No tension on the backstay?

[paul I]

No tension on the backstay?

In my experience the backstay on these boats does nearly nothing unless you want to try and bend the mast top a bit. I do have an adjustable one though.

[Tomfoolery]

Paul

I took the liberty of pasting your photo into AutoCAD and putting a photo of mine (taken fifteen minutes ago) right next to it. I rotated both photos a little so the boot stripes are horizontal, struck a line from the top of your mast to the bottom, and dropped in an angle dimension.* You can clearly see the bend in your mast, which scales to a little more than 4".**

I then copied the red line to my mast, and it lines up almost perfectly. I had pulled the main halyard very tight along the back (slot side) of the mast, and the red line sits right on top of it. Which tells me both masts are very close to the same amount of rake. FWIW.



This closeup is a bit grainy, but you can see the bend in the mast more clearly.



Mine has a little less, which scales to a little more than 2". Looks like mine could use a little more bend.



My upper side stays are tensioned to about 300 lb, and the lowers to about 270 lb, using the calibration I worked out using test weights. I'd have to decrease the lower tension a little to put more bend into the mast, and possibly increase the upper tension to compensate. But I've already taped up the pins and ringdings, and I'll go sailing (this week, I hope) with it the way it is. With my original, badly blown-out main, I don't think it's going to make much difference anyway.

*Angle from vertical is not what the manual says, but I measured 1-3/8" horizontal on 24" vertical with a framing square on the front of my mast, which is 3.3 degrees of rake. Using a heavy kellet off the main halyard, I got about 21.5" off-plumb, which is about 3.8 degrees of rake. But the little flat spot on the deck is tilted forward from level, so it's clear that angle from vertical is not the same thing.
**Scaling is a bit iffy, as the photos were taken from close-in and at ground level, so the horizontal measurement may be a little larger than reality.

[dlandersson]

My point is that it should be loose - it should NOT be "tight"

No tension on the backstay?

In my experience the backstay on these boats does nearly nothing unless you want to try and bend the mast top a bit. I do have an adjustable one though.

[paul I]

My point is that it should be loose - it should NOT be "tight"

OK, Yes the backstay is not even connected up. It will stay disconnected through the tuning process.

[paul I]

Tom,

Thank you for the analysis. I appreciate the work you did.

So if I understand this correctly, the mast rake, as I have it set now, is at least very close to where it should be. But I have about 1" too much prebend (what I've been calling bow) that I can try to remove.

To reduce the pre-bend, I'd want to reduce tension on the uppers just a bit (one hole probably). This will allow additional tension to be applied to the lowers without adding more pre-bend. Once that is done, I will need to re check the mast rake to stay close to the 4 degree recommendation (but I don't think that will change). Repeat until the mast looks a bit flatter and stay tension indicates about 300 lbs and 270 lbs on the uppers/lowers respectively.

Yes?

[Tomfoolery]

Tom,

Thank you for the analysis. I appreciate the work you did.

So if I understand this correctly, the mast rake, as I have it set now, is at least very close to where it should be. But I have about 1" too much prebend (what I've been calling bow) that I can try to remove.

To reduce the pre-bend, I'd want to reduce tension on the uppers just a bit (one hole probably). This will allow additional tension to be applied to the lowers without adding more pre-bend. Once that is done, I will need to re check the mast rake to stay close to the 4 degree recommendation (but I don't think that will change). Repeat until the mast looks a bit flatter and stay tension indicates about 300 lbs and 270 lbs on the uppers/lowers respectively.

Yes?

I think so, yes. If the forestay length remains unchanged, the mast rake would remain unchanged, too, assuming the forestay tension hasn't changed - wire rope is actually pretty stretchy, like long rubber bands, and the standard forestay is 1/8" (mine is 5/32", though, so a little less stretchy).

You might have to shorten the lower stays by 1/8" at a time (the vernier pitch is 1/8") as you lengthen the upper stays. What I would do in your deck shoes is what I've done in my deck shoes, and that's stretch the main halyard very tight along the back of the mast, terminated on the vang bail, if you have one, like in my photo. Then you can see the result right away as you adjust.

After all this talking it out, I decided to cut off the rigging tape that I had just put on the shroud adjusters, as well as the rigging wire on the forestay turnbuckle, and re-tune it for a little more pre-bend. I can't do it in the water easily, as I can't reach them from the deck (I've tried), and I don't want to keep turning the boat around to face the dock, so I'll bite the bullet and tweak it just a little more in the driveway and hope it doesn't change much in the water, full of ballast. At least it's relatively easy to adjust the forestay turnbuckle from the deck, or from the dock (I always dock it bow first).

[paul I]

Tom,

Thank you for the analysis. I appreciate the work you did.

So if I understand this correctly, the mast rake, as I have it set now, is at least very close to where it should be. But I have about 1" too much prebend (what I've been calling bow) that I can try to remove.

To reduce the pre-bend, I'd want to reduce tension on the uppers just a bit (one hole probably). This will allow additional tension to be applied to the lowers without adding more pre-bend. Once that is done, I will need to re check the mast rake to stay close to the 4 degree recommendation (but I don't think that will change). Repeat until the mast looks a bit flatter and stay tension indicates about 300 lbs and 270 lbs on the uppers/lowers respectively.

Yes?

I think so, yes. If the forestay length remains unchanged, the mast rake would remain unchanged, too, assuming the forestay tension hasn't changed - wire rope is actually pretty stretchy, like long rubber bands, and the standard forestay is 1/8" (mine is 5/32", though, so a little less stretchy).

You might have to shorten the lower stays by 1/8" at a time (the vernier pitch is 1/8") as you lengthen the upper stays. What I would do in your deck shoes is what I've done in my deck shoes, and that's stretch the main halyard very tight along the back of the mast, terminated on the vang bail, if you have one, like in my photo. Then you can see the result right away as you adjust.

After all this talking it out, I decided to cut off the rigging tape that I had just put on the shroud adjusters, as well as the rigging wire on the forestay turnbuckle, and re-tune it for a little more pre-bend. I can't do it in the water easily, as I can't reach them from the deck (I've tried), and I don't want to keep turning the boat around to face the dock, so I'll bite the bullet and tweak it just a little more in the driveway and hope it doesn't change much in the water, full of ballast. At least it's relatively easy to adjust the forestay turnbuckle from the deck, or from the dock (I always dock it bow first).

Ok it all sounds like a plan. Ill be trying it out tonight or tomorrow. I agree with doing all the adjusting on the trailer. Its a pain to get to those connectors when in the water. FWIW the last time I did tuning 3 or 4 seasons ago nothing seemed to change when going from the trailer to the water with respect to shroud tensions.

The other thing I was wondering was related to the furler. I have had issues in the past where the furler top (the black part) would rise up from the cup causing fouling of the furler line. Nothing actually connects the drum to the upper black housing and nothing prevents the housing, along with the foil and the rolled jib itself, from rising upward except gravity. To prevent this in the past, after all the tension adjustments were completed, I attached a spare spreader end cap to the top of the wire to allow no more than a 1/16" or so of vertical play on the foil. Has anyone else run into this?

[Tomfoolery]

Ok it all sounds like a plan. Ill be trying it out tonight or tomorrow. I agree with doing all the adjusting on the trailer. Its a pain to get to those connectors when in the water. FWIW the last time I did tuning 3 or 4 seasons ago nothing seemed to change when going from the trailer to the water with respect to shroud tensions.

Good to know. Thanks.

I just finished lengthening the lower stays 1/8" to add a little more bend into the mast, but as expected, the tension also dropped. So with the upper stays at about 300 lb, the lower stays are at about 200 lb. Increasing the lower stay tension takes bend out of the mast, and I only have about 2-1/2" or a little less as it is. So I'll try that for a while. The boat is coming back out of the water for a road trip to Cape Cod in July, so I'll make observations (especially mast pumping) and make adjustments if needed when it comes back out. Or if my dock neighbor is out for a while, I can just pull the boat sideways to the other finger and make adjustments, back and forth. Hopefully I won't have to.

The other thing I was wondering was related to the furler. I have had issues in the past where the furler top (the black part) would rise up from the cup causing fouling of the furler line. Nothing actually connects the drum to the upper black housing and nothing prevents the housing, along with the foil and the rolled jib itself, from rising upward except gravity. To prevent this in the past, after all the tension adjustments were completed, I attached a spare spreader end cap to the top of the wire to allow no more than a 1/16" or so of vertical play on the foil. Has anyone else run into this?

Assuming you have the FFII unit, there's a cross-pin that holds the drum down. It's a long, skinny pin with a small ringding to hold it in place. It fits through a hole in the foil. That locks the drum to the foil, but other than that, I don't believe there's anything else to hold the entire foil and sail from sliding up the forestay. Sounds like a spacer at the top is the way to go, preferably plastic. Buy I've never noticed a problem with the furler climbing up the forestay on my boat.