# Sticky  Adjusting Your Rig



## Giulietta

*Adjusting Your Rig, step by step.*

*Small introductory disclaimer (because you Americans love to sue people):

For the record it is my strong personal opinion and belief that any and all work performed in a boat's rig should be performed and done by appropriate professionals, (that know what they are doing, because I have seen too many "rig professionals" that don't have a clue of what they are doing), do it yourself only if you have at least 3 ounces of brain and if have been around boats long enough and know with a minimal amount what you are doing..If you don't, PLEASE DON'T TOUCH IT, IT's NOT FOR YOU.

If you damage your rigging, your boat and/or hurt yourself or others don't come here blame me..get a life, I wrote this for intelligent people only.

This I write bellow is to help you get by should you not find a rigger near you. IT IS FOR INFORMATION ONLY.*

*Now the post:*

A few months ago, one of our most dear friends here at Sailnet was stranded with a mast down problem, in a location where proper rigging professionals were scarce and the knowledge about rigging of the existing "rig professionals" was par to the local baker, veterinary and dentist&#8230;(I think he mentioned they were the same guy)&#8230;

So, and since he asked, I wrote him a small letter (sorry for the spelling mistakes and grammar), where I tried to explain to him how to set his rig in a way that would allow him to continue his journey and even get by in the future.

Please note this is my own experience, and other people may have better procedures..like I say, I am not a professional, and do this based on my own experiences. So if you don't like it, write you own and post here. It will only enrich the site. Please keep disagreements to PM level only, and I will discuss with you, should you not like or agree with me. Thank you.

*HOW TO ADJUST AND SET YOUR RIGGING:*

First you need understand this:

We will do 3 basic adjustment types:

•	*Lateral Adjustment
•	Longitudinal Adjustment
•	Sailing (done later) Adjustmet*

*1) Lateral Adjustment.*

(NOTE: this has to be done in a day with no wind with the boat perfectly horizontal, shift weight if you have to, to balance the boat).

a) Install the mast, and make sure the intermediate and lower shrouds are lose, but attached.

b) Make sure the stays and back stays are attached but not over tightened. At this point you want the mast as vertical as possible.

c) Remove the boom, or lower it so its not pulling on the mast, we will need the topping lift.

d) If the mast is keel stepped, remove the centering thru deck bushings at this stage.

e) Once the mast is up and vertical by eye observation, take the topping lift or the main halyard and measure the distance from the top of the mast to the boat's toe rail on port side. Repeat on starboard side, make sure the location of measure is symmetrical and at the same distance from the bow.
f) If the distances are not the same, tighten the side with the longest measurement.

g) Tighten the upper shrouds to a snug fit the same number of turns on each side, until the mast is perfectly centered.

*2) Longitudinal Adjustment. (Rake)*

(*NOTE*: this has to be done in a day with no wind with the boat perfectly horizontal, shift weight if you have to balance the boat).

Rake will help increase or decrease Weather helm. Aft Rake increases weather helm, improving pointing, forward rake does the opposite.

Normal rake is 1 to 2º degrees aft for cruiser boats and up to 4º deg aft for high performance racers.

a) Install a bucket with water under the boom by the mast.

b) Attach a heavy object to the main sail halyard and dip it the bucket but it should not touch the bottom of the bucket. (The bucket and water are used to dampen the swinging of the halyard.)

c) Measure P, which is the distance from the boom to the top of the mast.

d) Measure the distance from the halyard to the edge of the mast, at the gooseneck.

The distance should be as follows in the table:







*Note,* if you have a T shaped mast head, for halyard sheaves, add the distance of the T leg to mast to the above calculations.

Here is an example:

Our friend's mast is 42 feet long, or 12,8 meters, therefore for:

0,5º Deg rake = 11,52 cm = 4,33 Inches
1º Deg rake = 22,4 cm = 8,66 Inches
2º Deg rake = 44,8 cm = 17,3 Inches
3º Deg rake = 67,2 cm = 26,3 Inches

He also had a mizzen mast, and in his case, the mizzen mast has 21 feet, or 6,4 meters, therefore, for:

0,5º Deg rake = 5,76 cm = 1,96 Inches
1º Deg rake = 11,2 cm = 4,33 Inches
2º Deg rake = 22,4 cm = 8,66 Inches
3º Deg rake = 33,6 cm = 12,99Inches

e) Measure the distance from the halyard to the edge of the mast, at the gooseneck.

f) Adjust the rake as needed, using the above table, using the stays and triatic also, (should you have a triatic), don't forget that, ok?

g) Once all is where it should be, and the mast is where you want it, I would go with a rake of 1 º Deg for both masts for cruisers and 3% for racers.

h) Later on, once you sail, if you "feel" you need more rake use above numbers and adjust all again.

*Note* if you have a mizzen, for the triatic, you need a little help to get up there, but try to do it once with only one climb.

*3)Dynamic Adjustment. *

This will be obviously done later, if you feel you need more bend or better mast flexibility. See note further down, as at this stage we need to talk about tension in the rig.

The next step is therefore set the right shroud tension.

RIG TENSION​
*1) Shroud tension*

We now need to tension the upper shrouds, so let's tension them.
The values I calculated for our friend in the example are as follows:

a) All shrouds, including the upper, intermediate and lower are to be tensioned to 15% of the cable breaking load which in his case was:

3/16 cable the breaking load is 4850 lbs, so 15% of that is 727,5 Lbs

1/4 cable the breaking load is 7054 lbs, so 15% of that is 1058 Lbs

5/16 cable the breaking load is 12566 lbs, so 15% of that is 1885Lbs

b) The stays and triatic are to be set at 20 to 25% of the breaking load.

Use the same calculations above, to calculate the setting values, if you have a LOOS gauge, use it to set these tensions.

c) Now for the main shrouds, if you don't have a Loos, or are just a cheap person, you can use a measuring tape. I did for many years.

You will need to attach a tape of at least 2 meters to the shroud, so that the zero or the beginning of the tape starts at the turnbuckle.

The rule is simple each 1mm of stretch means 5% of the breaking load, and that is valid for *ANY CABLE IN A SHROUD*, no matter what the diameter is!!!

So you want to have at least 3mm of "growing" or 0.11 inches stretch when you're at the right tension, for 15% tension&#8230;cool huh??

Simple. Repeat the other side. Don't do all 3 mm in one go. Do 1mm on each side and measure and adjust slowly so you don't throw the mast off alignment.

Once the upper shrouds are tensioned, go to the next step.

*2) Mast Pre bend*

Once the masts are where you want them to be, and before we tension the shrouds, we need to set the masts curvature, or pre-bend.

For this attach the halyard that was in the bucket so it ends at the mast foot.

Now adjust the baby stay and or forestays so that the belly of the mast goes forward. Takes a few tries.
The max bend at rest should not exceed half of the mast diameter.

3) *Max Mast bend* (back stay and or triatic if you have one)

Tension the back stay on the mizzen first, (if you have one), so that the distance from the vertical halyard to the mast is half of the mast's diameter (IMPORTANT - DO NOT EXCEED)

The mast bend when the back stay is pulled should never ever be more than 2% of the height of the mast from the top to the deck (not cabin). In our friends case with a 42 foot mast, at full back stay pull the mast top should not move back more than 10 inches. OK?

*NOW IN THE WATER!! Dynamic Adjustment continuation of chapter 3 above*.

OK so where are you going to set the intermediate and lower shrouds??

*LOWERS*

Easy. At dock, adjust the lowers so they are just tensile to the finger, use the Loos to set them equally port and starbord, they should be almost flexible at rest. Hard but not too much. These can only be adjusted once you sailed to measurel.
*
INTEMEDIATES*

also at dock, Should have a flex of about ½ inch when at rest.

* 
The lower shrouds adjustment *

Now, when you go sailing, on the first tack, see if the mast is vertical and doesn't bend sideways when you are on a tack.
Look from underneath and see if it's straight.

If the mast bends to leeward, kind of like bellies to the low side, the lowers are too flexed.

Go to the lee side lower, and turn it a few turns, and note how many times you turned.

Then tack to the other side and see if its good. If its still bent, go on the lee side one and do the same number of turns plus a few more, repeat tacking and adjusting till all is good and straight.
*
The Intermediate shrouds adjustment*

It's the same as with the lowers, except now it's the top part of the mast that "bends" to leeward if they are lose.

Those only adjust at the marina, ok??? You need to go up there.
*
So a recap:*

1) Tighten by hand the upper shrouds till the mast is straight.
2) Adjust mast rake with stays and backstay/triatic.
3) Tension upper shrouds to 15% breaking load
4) Adjust mast pre-bend
5) Adjust back stay movement to not more than 2% mast lenght
6) Adjust lower shrouds while sailing
7) Adjust intermediates observing while sailing and adjusting at dock

Have fun.


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## merlin2375

NICE post, very useful information!


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## max-on

Giu, next time call me first about the disclaimer, we'll make the language stronger!!!


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## Idiens

Thanks Giu


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## TSOJOURNER

Wow, impressive post Giu. Thanks for that.


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## Valiente

Alex, if I corrected the very few errors in this, it wouldn't sound like you anymore. Excellent advice, and it's good to know we tune essentially the same way, breaking it down into "at dock" and "underway" procedures.

I have 1/4" stays on the old, more race-oriented boat, and I swear since I learned about tuning I get a great deal more performance out of it, even though my back stay is fixed (no Navtec lever or wheel or ram). 

A point here about tensioning: Don't bother trying to align your prop shaft and coupler until AFTER you have tuned the rig, at least at dock. I don't care for saildrives, but one advantage is that this problem of a tensioned rig "bending" the boat slightly is avoided. If you have the most common cutlass bearing and spade rudder set-up, align the coupler at launch just to motor to your dock and to the mast crane (if your mast is out). Tighten the stays just enough to keep the mast up, and then go back to the dock for a beer. If it's calm and you aren't drunk, follow Alex's fine instructions. Tune the rig at dock.

Leave the boat. Wait a couple of days. Come back and see if your prop shaft is still aligned. Maybe it isn't. Realign it now that the boat is bent according to the rig tension and not because it's been drooping off a cradle or jackstands all winter. You will probably find enough of a misalignment to make you glad you checked it out.


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## xuraax

Gui,

Thanks for an excellent set of instructions.

I have read through your post a couple of times already but I still need to reread it several times more to appreciate all its contents.

There are 2 comments I would like to make, always with due respect.

1. it would help to define the various types of stays on the mast for us non English readers.This to unsure that we correctly tighten the correct stay.

2. At one point you said you calculated the strength to be 15% of breaking strength. How do you arrive at this figure?

By the way you are spot on in your DISCLAIMER.

thanks again

xuraax


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## jrd22

Disclaimers don't mean squat anymore (who's smart enough to understand them?), you'll probably be in the middle of a class action suit soon from all the unemployed riggers that your information put out of business. 

Thanks Alex, timely info., I should be stepping the mast within a month and I'll have this printed out and with me when I do.

John


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## Giulietta

xuraax said:


> Gui,
> 
> 1. it would help to define the various types of stays on the mast for us non English readers.This to unsure that we correctly tighten the correct stay.
> 
> 2. At one point you said you calculated the strength to be 15% of breaking strength. How do you arrive at this figure?


Xuraax,

*It's GIU !!!! Damn it!!!! * (inside joke...don't worry) 

Now, for your information, I have learnt the technical english they use in the United States, so that you know I use (with some difficulty) their terms.

*Stays* are all cables and/or lines that pull the mast in the longitudinal axis, forward or backwards, such as Fore stay, Stay, back stay, baby stay and Triatic (for mizzen masts).

*Shrouds* are the ones that are located on the sides, normally attached to chain plates, and pass thru the spreaders.

As far as the 15%, I said I had calculated it, but it was in response to a question my friend had asked. He sails a heavy cruiser in moderate to heavy winds, and 15% seemed like a good all around value for his case.

Shroud tension should vary between 10% and 20% of wire or cable breaking load. and stay between 15% and 30%.

Also the tension settings should vary with the prevailing wind strenghts the boat normally sails in. 10% shroud tension would be better as far as performance is concerned for a boat sailing in moderate winds, 20% should be better for racers and or for boats sailing in heavier winds, where less flexibility is desired.

In your case, and since I know Malta very well, and you want to race, 20% should be the right setting, and 25% for the stay.


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## KeelHaulin

Again; nice writup Giulietta. I was wondering about the difference between rake and pre-bend. When you measure pre-bend is that in addition to the rake? So first you measure the rake and then you put additional pre-bend on the mast?

I also have a question regarding the wedging at the cabin roof for a keel stepped mast. "Spartite" was installed at the partners so I can't remove and replace wedges. Can I add rake and bend with the Spartite in place or would trying to rake the mast at this point only result in bending? The mast already has a factory taper and pre-bend IIRC; it's a tall rig, the I is 52'. Visually I don't see much rake; but there is bend above the upper spreaders.


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## Giulietta

KeelHaulin said:


> Again; nice writup Giulietta. I was wondering about the difference between rake and pre-bend. When you measure pre-bend is that in addition to the rake? So first you measure the rake and then you put additional pre-bend on the mast?
> 
> I also have a question regarding the wedging at the cabin roof for a keel stepped mast. "Spartite" was installed at the partners so I can't remove and replace wedges. Can I add rake and bend with the Spartite in place or would trying to rake the mast at this point only result in bending? The mast already has a factory taper and pre-bend IIRC; it's a tall rig, the I is 52'. Visually I don't see much rake; but there is bend above the upper spreaders.


Look here:










KH..the bend is mesasured by bringing the halyard you used to set the rake to near the mast foot, so you can measure it, by measuring the distance between the halyard and the mast, and this is obviously independent of the rake, since the halyard starts at the mast head and comes to the mast foot, and that happens even if the mast is lying down on the floor.

technically, the bend should be there independent of the rake, that is why you set the rake first and the bend after. Now the bend can be increased at a later stage by the backstay, if you have one.

As far as the mast thru deck seal..obviously it would be better if it was not there, as the thru deck is creating a "pivoting point" in the mast, thus affecting the ability to properly set rake and bend.

But if you can't remove it, "he that doesn't have a dog, can hunt with a cat", as we say in my country.

The rake can to some extent still be set but I doubt you can get better than 3 deg rake, as it will start bending, yes.. Give it a try..

If you knew how many people I know that complain about boats with excessive or lack of weatherhelm that are sailing boats with wrong rake, you would be surprized....

The tapper is to reduce weight aloft, make the top more flexible and make the mast loom good, and less "tree stump" on the top... the bend is done once on the boat, not at the factory..they ship them straight as a whistle..


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## KeelHaulin

guilietta said:


> The rule is simple each 1mm of stretch means 5% of the breaking load, and that is valid for *ANY CABLE IN A SHROUD*, no matter what the diameter is!!!




Careful... I did some basic calcs on this and yes; for an equivalent diameter _and equivalent length_ the linear stretch is roughly proportional to tensile stress regardless of diameter. BUT if the smaller diameter shroud is smaller in length (which it should be) then the amount of pre-load you apply per mm of stretch is increased. That's because strain = change in length / original length.

Example:

Let's say you have a 50' mast with 7/16 upper shrouds. The calculations I did suggest that you would need 5.98 mm of stretch applied to them to get ~1600 lbs of pre-load.

In the same example; if the shrouds were 1/4" you would also need to stretch them 5.98mm to achieve 540 lbs of pre-load.

But; if you have a shorter mast (as you should) with 1/4" wire the stretch required to get 540lbs of pre-load will be less. If the mast is 30' tall the stretch required will be 3.6mm to get the same 540 lbs of pre-load. If it were tightened to 5.98mm it would have roughly 900 lbs of pre-load or 25% of break load.

So; while the rule-of-thumb is probably OK for a rough tune I would say that if you apply it to taller rigs it will result in shroud tensions that are on the loose side; and on shorter rigs it will result in shroud tensions that are a bit too tight. 


Thanks for the additional info on rake VS bend. I understand it now; and now I'm not sure if the mast actually has rake or not. I'll do some measuring and adjusting according to your excellent procedures.


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## jimmyb116

Ok but when and how do you adjust the baby stay?


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## xuraax

Giu,

Sorry for getting your name wrong. This thread simply has to much info for me to appreciate all of it at one go.

I guess I was not clear enough when I asked for clarifications on the various terms. I have tried to upload a picture of the rig to clarify but for some reason Sailnet is not accepting the file.

So I will try with words.

The rig I am interested in has a twin spreader rig consisting of a wire *A* starting from the deck to the tip of the first spreader then to the tip of the second spreader and then on to the mast.

It also has a wire *B* starting from the same place as *A* going up at an angle to the mast at the lower spreader height.

There is a second wire *C* going up at an angle from the outer tip of the lower spreader to the mast at the height of the upper spreader.

I guess my question is: what are the names of wires *A,B,C*?

regards


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## lharmon

Giulietta

Thank you for your hard work and effort. You saved me from starting a thread about how to check and adjust my rig's tension. The various stays are all over the place tension wise and I planned to re-tension around launch.

All these good deeds you do for us will hopefully earn you a nice bunch of beam reaches this season.

Thank you very much.

LH


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## denby

Thanks Alex, 


Great post.


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## blt2ski

xuraax,

Using Alex's examples under rig tension, 1) shroud tension, 

A would be upper shroud, 
B lower shroud
C intermediate shroud. 

Alex,

Thank you for info, this is tomorrows list to do before saturdays race, or sunday if not time if found tomorrow friday. Got a loose guage the other day too!

Marty


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## xuraax

thanks a lot Marty.

Rereading Alex's mail several times I was deducing the same thing but being a pessimist it feels good to get a confirmation from others.


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## Giulietta

KeelHaulin said:


> [/FONT]
> 
> Careful... I did some basic calcs on this and yes; for an equivalent diameter _and equivalent length_ the linear stretch is roughly proportional to tensile stress regardless of diameter. BUT if the smaller diameter shroud is smaller in length (which it should be) then the amount of pre-load you apply per mm of stretch is increased. That's because strain = change in length / original length.
> 
> Example:
> 
> Let's say you have a 50' mast with 7/16 upper shrouds. The calculations I did suggest that you would need 5.98 mm of stretch applied to them to get ~1600 lbs of pre-load.
> 
> In the same example; if the shrouds were 1/4" you would also need to stretch them 5.98mm to achieve 540 lbs of pre-load.
> 
> But; if you have a shorter mast (as you should) with 1/4" wire the stretch required to get 540lbs of pre-load will be less. If the mast is 30' tall the stretch required will be 3.6mm to get the same 540 lbs of pre-load. If it were tightened to 5.98mm it would have roughly 900 lbs of pre-load or 25% of break load.
> 
> So; while the rule-of-thumb is probably OK for a rough tune I would say that if you apply it to taller rigs it will result in shroud tensions that are on the loose side; and on shorter rigs it will result in shroud tensions that are a bit too tight.
> 
> 
> Thanks for the additional info on rake VS bend. I understand it now; and now I'm not sure if the mast actually has rake or not. I'll do some measuring and adjusting according to your excellent procedures.


KH..I don't know how you did your calculations, but I confess you are puzzling and confusing me a lot...

where did you get the numbers and are you sure about the values you are using for breaking loads?

Normally 7/16 cable which is around 11mm has a BL of 27.815 lbs, roughly (as my tables are metric)..and a stretch of 5.98mm as you suggest is 30% not 6%, as that is the stretch for the 1600lbs you are refering to.

a 1/4 cable that has a BL of 7054 lbs roughly, at 900lbs it is at 13%...


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## xuraax

From the web, Young's Modulus for 1x19 wire rope is 107.5 kN/mm^2.

Using the table of breaking loads for different diameters of AISI-316 wire rope as given in the book "Principles of Yacht Design" I got the following table for wire stretch for a 2000mm wire loaded to 5% of breaking load:

diameter(mm)____breaking strength(kN)___delta L(mm)

3_______________7.7__________________1.01
4______________13.8__________________1.02
5______________21.6__________________1.02
6______________30.o__________________0.99
7______________40.9__________________0.99
8______________53.5__________________0.99
10_____________69.1__________________0.82
11_____________83.5__________________0.82
12____________120.2__________________0.99
14____________160.1__________________0.97

This practically confirms what Alex is saying.

regards


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## tdw

Alex,
Thanks kiddo. Got it this time.
Cheers

A


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## KeelHaulin

xuraax said:


> From the web, Young's Modulus for 1x19 wire rope is 107.5 kN/mm^2.
> 
> Using the table of breaking loads for different diameters of AISI-316 wire rope as given in the book "Principles of Yacht Design" I got the following table for wire stretch for a 2000mm wire loaded to 5% of breaking load:
> 
> diameter(mm)____breaking strength(kN)___delta L(mm)
> 
> 3_______________7.7__________________1.01
> 4______________13.8__________________1.02
> 5______________21.6__________________1.02
> 6______________30.o__________________0.99
> 7______________40.9__________________0.99
> 8______________53.5__________________0.99
> 10_____________69.1__________________0.82
> 11_____________83.5__________________0.82
> 12____________120.2__________________0.99
> 14____________160.1__________________0.97
> 
> This practically confirms what Alex is saying.
> 
> regards


Right; I said the same thing. If the shroud length is constant; the amount of stretch required is the same. But * you can't apply this universally to all shrouds because different boats have different lengths of rigging wire.* If you plug in 4000 mm for your base length; the delta L will double to get the proper tension. Since that's true you can't use the 1mm/5% rule to get exact tension. If I tighten an intermediate 1/4" shroud using that rule the tension will likely be ~40-50% of breaking load because the shroud lenth is much shorter than the upper shroud; which goes from the masthead to the deck.

Giu-

I'll get back to you with the data; I am aboard my boat tonight using a different computer. I should still have the spreadsheat I was doing the calc's on; but if not I will make up a new one. I was just using the modulus for 316 stainless and an approximate breaking strength for each size. Please don't use those numbers I posted as "actual"; I was only trying to make the point that stretch is also dependent on wire length (and this is independent of the max strength of each wire diameter).


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## Giulietta

It's ok, Keel..its best to use a Loos gauge.

Go here and download the stretch calculator, instead.

And instead of stretch use the force. I use a Loos gauge...I bought 3 from the old sailnet...

Loos Gauge

PRICES


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## xuraax

KeelHaulin said:


> Right; I said the same thing. If the shroud length is constant; the amount of stretch required is the same. But * you can't apply this universally to all shrouds because different boats have different lengths of rigging wire.* If you plug in 4000 mm for your base length; the delta L will double to get the proper tension. Since that's true you can't use the 1mm/5% rule to get exact tension. If I tighten an intermediate 1/4" shroud using that rule the tension will likely be ~40-50% of breaking load because the shroud lenth is much shorter than the upper shroud; which goes from the masthead to the deck.


Keel,

As I understand it, if you mark off 2m of a shroud 6m long and then tension it to 10% of its breaking strength you should find that the marks that you made are now 2.002m apart.

If you mark off another 2m of a shroud that is 10m long and you tension this shroud to the same amount your 2 marks will again measure in at 2.002m apart.

this sound logical to me but hey...I am no expert, I could be wrong.

regards


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## Mikelivingstone

Hello Xuraax, Since u r in Malta and sail u r doing the Marzamemi race next weekend! Good luck with your rig tuning and d race if you are doing it.

Regards

Mike


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## xuraax

Mikelivingstone said:


> Hello Xuraax, Since u r in Malta and sail u r doing the Marzamemi race next weekend! Good luck with your rig tuning and d race if you are doing it.
> 
> Regards
> 
> Mike


Hi Mike,

Pleasant surprise. Yes I am doing the Marzamemi race. Are you?

regards


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## Mikelivingstone

Don't know yet, I crew for Willy on Bordeaux 3, But I have to be in Brussels on Sunday so I will probably have to miss it. Which boat r u on? 

Mike


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## xuraax

i crewed once on Bordeaux 3 about 3 years ago. I am on Sailaway an Elan 37.


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## Mikelivingstone

Saw u practising on Sat afternoon, give my regards to rayair.


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## KeelHaulin

OK; here is the way to solve for stretch at 15% breaking strength. It's a simple derivation; it really only uses two well known engineering equations to solve it.

Strain is defined using the greek symbol epsillon; I'm using *E*

Strain is defined as:

*E* = dL / *Lo*

Change in length is dL; *Lo* is the Original Length.

For elastic conditions; we can use the definition of Young's Modulus to determine how much extension (strain) exists in a length of wire for a given amount of force applied.

Young's Modulus - *E *= Applied Stress / Strain = S/*E *= S/(dL/*Lo*)

Young's Modulus is a material specific constant measured by a testing applied force vs extension.

For type 316 Stainless; *E *= 28,000 kPSI

We can solve this for the change in length; dL

dL = *Lo ** (S/*E*)

The only real "variable" in this equation is *Lo*. For all wire diameters we want the same amount of stress (15% of breaking) so we can say that S is a constant.

Let's calculate S for some different wire diameters to prove it's relatively constant:

S = (F/Ao) - "F" is the tension force in the wire; Ao is the original cross sectional area of the wire.

(Breaking strengths taken from loosco.com for 1x19 type 316 wire)

For 7/16 wire - S = 15% * (20,000#)/(Pi * (7/32")^2) = 15% * 133,040 PSI = 19,956 PSI

For 1/4" wire - S = 15% * (6900#)/(Pi * (1/8")^2) = 15% * 140,560 PSI = 21,084 PSI (within 5%)

For 5/16 wire - S = 15% * (10,600#)/(Pi * (5/32")^2) = 15% * 138,200 PSI = 20,730 PSI (within 4%)

Using Young's Modulus for type 316; the 15% breaking load equation becomes:

dL = *Lo* * (20,600 PSI) / (28,000 kPSI) = *Lo* * .000736.

Use inches or mm for the shroud length; multiply by .000736 and get the length you need to stretch the cable.

For a shroud 55' long: dL = 660" * .000736 = 0.485"

For a shroud 20' long: dL = 240" * .000736 = 0.177"

It's -fairly- independent of wire diameter; but clearly dependent on length! You could use this for type 316; (but of course the standard disclaimer applies); and it does not take into account deflection of the rig or hull when you tighten the shrouds. Again; you should use an appropriate tension gauge to determine the actual rig tension.


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## Cruisingdad

THis is an outstanding thread, and I want to commend all who participated and especially Alex for a very, very good detailed explanation.

Super job!!

- CD


----------



## xuraax

KeelHaulin said:


> For type 316 Stainless; *E *= 28,000 kPSI


Keel,

When I convert your number to metric I come up with 193KN/mm^2 which is a lot higher than the one I quoted (107.5). When I looked up E again on the web the numbers I come up with now are closer to the ones you give so I guess it is more proper to use the constant you gave. The equation for Delta L is of course the same (Phewww!! thank goodness for that)



KeelHaulin said:


> For 7/16 wire - S = 15% * (20,000#)/(Pi * (7/32")^2) = 15% * 133,040 PSI = 19,956 PSI


I note that American's frequently use the # sign. Can you explain what it means?



KeelHaulin said:


> Use inches or mm for the shroud length; multiply by .000736 and get the length you need to stretch the cable.
> 
> For a shroud 55' long: dL = 660" * .000736 = 0.485"
> 
> For a shroud 20' long: dL = 240" * .000736 = 0.177"
> 
> It's -fairly- independent of wire diameter; but clearly dependent on length! You could use this for type 316; (but of course the standard disclaimer applies); and it does not take into account deflection of the rig or hull when you tighten the shrouds. Again; you should use an appropriate tension gauge to determine the actual rig tension.


I can understand the apparatus needed to measure an extension of a few mm over a length of 2 m.

What would you use to measure the 0.485" (say) in the 55' shroud to ensure that you don't tension it more than 15% of breaking strength?

regards


----------



## Giulietta

Just use a LOOS...oK?? just use a LOOS...

Use of the tape is only if a loos is not available....


----------



## blt2ski

xuaraax,

The # sign can mean a few things

# ie lbs in this case lbs of force before it breaks,

or 

I use it at work for "square unit"......unit typically being a foot of measure, meter, yards etc could also be used as the unit of measure.

My first option, ie lbs of breaking strength, could in some instances, be kilograms or equal force measure too, but lbs is most common. 

Marty


----------



## soul searcher

I went through this process recently and may be able to save someone some trouble.
The elongation method is a pain get the Loos gauge from the start.
This process requires patients. don't try to set the mast in column and lock it down at the dock. It wont work. The only way to get it right is to get the mast centered in the boat with the right rake and prebend and then do the rest undersail.
to do this right you can count on it taking forever. To get no wind and no wave action to get the mast in column at the dock is hard. then doing the real tuning under sail in the wind speed you want to tune for may require several outings and a lot of tacking.
Don't kid yourself that you can put the mast in collum and lock it down at the dock. the real tuning part can only be done under sail, with a load on the mast and stays. There is no short cut here! 
I tuned my rig for twenty knots I figured that was good middle ground for us.
And did not exceed 15% on the lowers 20% on the caps.
I maybe the exception, Our boat was layed up for a long time when we bought it and I don't believe the rig was kept in tune pryer to that so i had a hard time getting things adjusted. I tried moving the mast with the stays at first and finally just loosened everything and started from scratch. And followed a procedure much like the the one Giu. posted. 
Then after all the headache. and some help from Alex I finally got it right. I can drive with my finger tips on the wheel, my weather helm went down and the boat points higher and is faster. 
A couple things that I found out were that ambient temperature has a big effect on tension and I have a hatch just aft of the mast. It was a lot easier to sight up the mast from the salon looking up through the hatch than trying to to do it at the base of the mast. 
When the rig is right it makes sail trim and helm balance so much easier.
I look at it like this. if the foundation is crooked the house is crooked. There is no way you can get proper sail shape with the rig being out of wack.
If the center of the mast is falling off to leward then you cant flatten your main in heavier air. just when you want to depower the sail it's gettig powered up. The same as running loose back stays will add power to a jib.
It was an enjoyable process for me the results were well worth the effort.

Hope this helps


----------



## blt2ski

I bought a PT2 Loos gauge the other day. I have 7/32 wire on everything but the mid upper shrouds. which I believe is either 5/32 or 1/8. This is not listed as to what I need to check with current gauge. Does any one know how to figure out what the smaller wire number should be with the bigger gauge. As I really do not want to go buy a 2nd gauge for the smaller shroud. 

Guessing by how the three sizes go, I should be able to halve the numbers for the 3/16 which is the smallest size for the gauge I have and work pretty close for the next size down. any one care to say I am correct, not quite right.........

I may in the end, email loos and see if they have it figured out.

Marty


----------



## tenuki

blt2ski said:


> Got a loose guage the other day too!
> 
> Marty


got sick of borrowing mine eh?


----------



## blt2ski

LOL,

Actually got the same size, but the pro model vs your one level down. It was tempting to get the battery operated one tho! 

You got crew for wed night racing yet? If not, we will be out, and I am sure with 15'ish boats out normally for summer racing, someone will want a hand.

Marty


----------



## KeelHaulin

xuraax said:


> I note that American's frequently use the # sign. Can you explain what it means?
> 
> What would you use to measure the 0.485" (say) in the 55' shroud to ensure that you don't tension it more than 15% of breaking strength?


# for American "Engineering Notation" is Pounds. It can be either LBF or LBM; it's just a shrot-hand for Pounds because it's called the "pound" symbol.

To measure the 15% tension I'd just use a standard Loos Gauge. Although the calculation predicts 0.485" extension I would not bet my life on it. Young's Modulus is a theoretical constant for the material and it is calculated based on lab results under ideal conditions (perfect sample, solid section, etc.). If the theoretical is within 20% of the actual tension in LBF I'd call it a good comparison; but that's not as close as you would get with a Loos Gauge.

If you wanted to measure the extension I would put a pair of calipers on the open body turnbuckle and measure the distance between the threaded ends. That's a direct measure of the amount of elongation you are putting into the shroud.


----------



## knothead

jrd22 said:


> Disclaimers don't mean squat anymore (who's smart enough to understand them?), you'll probably be in the middle of a class action suit soon from all the unemployed riggers that your information put out of business.
> 
> Thanks Alex, timely info., I should be stepping the mast within a month and I'll have this printed out and with me when I do.
> 
> John


John, I don't think too many riggers will be put out of business or even resent the fact that there is good info available. 

I posted the following awhile ago. While not nearly as in depth or comprehensive as Alex's perhaps it has it's place.

The first part speaks to inspections while the rest addresses tuning.

"While not intending to dismiss anyone's advice, I am going to try to simplify this whole process. 
Cracked swages are really not too difficult to find. Clean the surface of the fitting with a scotch-brite (it helps if you spit on it before scrubbing), then take your magnifying glass and look very carefully over the whole thing. Don't neglect to inspect the clevis and cotter pins/rings. 
I've even seen a fairly young marine eye with absolutely no swage cracks split above the clevis pin.
If you have swage cracks they will be visible, if not obvious. 
If your rigging is more than ten years old and it has been in central Florida for all that time then you are likely to find a crack or two. 
If you find a small crack in your starboard upper and you have reason to believe the rigging is all of the same vintage then you will probably find some more upon closer inspection. 
If you only have one week off from work, (and it's next week), and you have been planning this trip to Honeymoon Island for months and you have sense enough to reef early, stay at anchor or motor if you think you are stressing the rig, then you can almost assuredly enjoy a nice vacation and then rerig when convienent. Certainly before you decide to do the thursday night beer can race at the yacht club.
I've seen, and continue to see neglected and poorly designed rigging stand up to amazing abuse. 
That said, you never want to push it. If you have time to rerig before your trip, then do it. If you can't, then take it easy, be smart and have a nice trip.

Most rigging, made by a professional will be consistant. Meaning that your starboard upper shroud will be almost exactly the same length as the port upper. (+or- 1/8" to 1/4"). So, if your mast is standing, then adjust your upper shroud turnbuckes exactly the same by opening them to the same point while your mast is being held by the lowers,headstay and backstay (you may even want to open the turnbuckles up completely and make sure the stud and t-bolt, ie top and bottom are started evenly). 
Then while tightening, count the turns and take up the exact same count on each side until hand tight. Now ease off the lowers one at a time and set them all hand tight. 
Next ease and set to hand tight the backstay and headstay, (if ajustable or accessable depending on furling systems). Now stop and sight up the main sail track like a gunbarrel. You will be able to see any curve (side to side) or bow (Fore and Aft) right away. 
If the mast is curving to starboard and bowing forward, then start to adjust it out by tightening the starboard forward lower and backstay. It's all pretty logical if you just remember that you want to keep the top of the mast in the middle of the boat. So move the middle of the mast. 
I realize that one must assume that the last rigger made the rigging correctly. 
That the builder put the hole or the mast step in the middle of the deck and the chainplates are the same length and in the same positions, but what the hell, you have to make some assumptions in life.
It's really pretty easy to see if a rig has been piece-mealed and as for the rest a tape measure will answer most questions if you are really worried. 
Anyway, back to the tuning.
Now that you have the mast in column, It's time to go for tentioning. If you have a gauge the use it. Set the shouds at the same tension, somewhere around the middle of the scale.

The most important part is to do the same thing on each side. If you turn the starboard upper three full turns then turn the port upper the same. Port aft lower two turns, Stb aft lower two turns etc.

If you don't have a gauge then just feel them. Don't try to make them sound like a guitar string but just get them tight. Tighten the uppers more than the intermediates and the intermediates more than the lowers. This assumes that the uppers are of an equal or larger diameter that the intermediates and the intermediates are of an equal or larger diameter than the lowers.

I have never seen a mast bowed forward on purpose. Lots of masts bow aft, some even are designed that way. Unless you have a in-mast main furler you probably won't have to worry about a little aft bow.
As far a rake (how much the mast leans aft from vertical), that can also usually be determined by the adjustment of the turnbuckles, Furlers and backstay adjusters. 
If you have turnbuckles on both the HS and BS then go for about 50% adjustment on both. Adjust that later depending on weather-helm or lee helm.
After you have successfully tightened all the shrouds and stays to a reasonable degree, the mast is in column side to side and you have the desired amount of bow then go sailing. In a moderate breeze, sailing a close reach your mast should still be in column and there should be no shrouds swinging in the breeze. Meaning that even the looward shrouds should still be under some, if smaller load. If not then adjust the loose shouds, counting the turns, come about and do the same thing on the other side. 
Again, the same turns on each side. Keep it in column.

If your headstay deflects too much and you can't sail too well to winward then tighten up the headtstay or backstay depending on weather/lee helm (you might want to ask a knowledgeable friend or racer to go sailing with you for this)
After returning to the dock, eyeball up the mast again. If necessary, make whatever minor adjustments to make sure the mast is in column then install all the cotter rings/pins. 
Congratulation,you're done
I have not made it a practice to go sailing on the boats that I tune. Don't have the time. Most riggers don't. As a sailor, it's a skill that one needs to aquire. 
Good luck and happy sailing"


----------



## Giulietta

Knothead, thanks for the good post, it enriches everyone's expereinces here to have guys like you around, thanks.

I don't have time to make one, but do you know where one can find the shroud breaking loads tables according to thickness, that shows both metric and imperial?

It would be good to add it here, if someone cares to do it. Thanks

Alex


----------



## knothead

Giulietta said:


> Knothead, thanks for the good post, it enriches everyone's expereinces here to have guys like you around, thanks.
> 
> I don't have time to make one, but do you know where one can find the shroud breaking loads tables according to thickness, that shows both metric and imperial?
> 
> It would be good to add it here, if someone cares to do it. Thanks
> 
> Alex


Alex, most of the catalogs that list Stainless wire used to have the breaking strengths listed for the various types. I seem to remember they sometimes listed safe working loads too. I'll look around and see if I can't find something.

Then I'll try to figure out how to scan it and then attach it. I'm not really adept at that stuff though.


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## xuraax

soul searcher said:


> I tuned my rig for twenty knots I figured that was good middle ground for us.
> And did not exceed 15% on the lowers 20% on the caps.


How does one go about optimizing the rig for 20Knots?

The rig I would like to set is a twin spreader aft swept 7/8 rig with a set of lowers and intermediates. The mast is a keel stepped affair. The mast is held firmly at deck level but the base can be moved fore-aft.

Currently the boat is getting quickly overpowered in high winds, constantly broaching into the wind in the gusts. It looks like pulling hard on the backstay and cummingham has little effect in flattening the middle part of the sail.

My other problem is that I do not own the boat so, of course, before playing about with other people's stuff one must be extra careful on what one is doing.

From the excellent info found in this thread I conclude that, for this rig setup,
the rake will be determined by the forestay length while the prebent will then be primarily determined my moving the mast base fore-aft keeping the shrouds fairly tight. The uppers should then be set to the 15% loading mentioned earlier.

It would seem then, that to optimise the rig for 20knots, say, one has to play about with the lowers and the intermediates.

Currently reducing the tension on the lowers results in some significant bending of the rig forward when pulling the backstay but the bent is nowhere near the 2% of mast length originally mentioned by Alex. Also the leeward shroud now becomes fairly floppy when sailing at 20knots so I am not sure if we have created another problem with the mast bending to leeward.

By the way, getting a rigger with a loos guage did not help much as apparently all he did was set the tension in the upper shrouds in port and more importantly the broaching problems remained.

regards


----------



## KeelHaulin

I think we need to know what type of boat you are sailing to determine if the problems you describe can be associated with the rig or not. Some issues with broaching or helm balance are more associated with the sailplan or a particular hull design and without knowing these things I can't say whether or not it is due to improper adjustment of your rig.


----------



## xuraax

KeelHaulin said:


> I think we need to know what type of boat you are sailing to determine if the problems you describe can be associated with the rig or not. Some issues with broaching or helm balance are more associated with the sailplan or a particular hull design and without knowing these things I can't say whether or not it is due to improper adjustment of your rig.


The boat is an Elan 37. The sails are Tape Drive racing sails.

Asking around on the WEB indicates that this boat does pretty well on the racing circuits even in high winds.

By the way I am not not necessarily saying that the rig is set up incorrectly. Merely that it is another paramater to check.

regards


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## xuraax

Gee...this thread has gone all quiet all of a sudden!!!


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## KeelHaulin

Seems to me that your boat is similar in design to the J-105; in rated area and size, etc. I can't say for sure about the sailing properties because it appears that Elans are primarily sold/sailed in Europe. The listings on Yachtworld only show them available in Europe/UK. That's why I hesitate to say exactly what the problem is.

If I were betting; I'd say that the problem is due to the high SA/D ratio and that the boat is getting overpowered earlier than a heavier boat or a boat with less sail area. The J-105 fleet racers say that they are a beast in heavy wind and they are always cranking the backstay up and spilling the traveler down to keep the boat on it's feet; of course they are pushing it to the limits when racing in their fleet. These tactics also require a crew who is constantly trimming and "rail meat" to help stabilize the boat.

Again; I'd try reefing it down good and then see how the boat performs. You'd be amazed that when you reduce sail area; your leeway reduces, the boat stands up and is able to sail at a more optimal angle of heel and can actually go faster. Your pointing might be a bit reduced depending on sail shape but hey if the boat goes faster and is easier to control you are going to make your destination more quickly and with less struggle.


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## Giulietta

Xuraax,

I remeber writting something to you about your boat not long ago SEE HERE (I even was criticized a few posts after, when I know the boat, and know what it can do, from being on them, not from reading in magazines or bla bla bla)...

I had told you once that somethings are just the way they are, and must be changed to act differentely.

What happens is your boat may be dressed like a race boat, smell like a race boat, be among racer boats, even looks like one, and sometimes go fast as one, BUT it is not a race boat.

It's a fast normal production boat that can be sailed faster than normal and faster than the others..(but it's limited to a wind envelope)...

It still behaves like a cruiser, even if you add rake, tension, etc. It's a cruiser...designed as a cruiser, has a cruiser keel, and rudder, and hull shape...

You need to modify the keel, modify the rudder, lighten the boat, and make the boat go thru a racing oriented modification for it to handle the winds in Malta..specially when you start getting above 18kts.

There is little you can do without modifying it... you need to have a fast main traveller system, longer and thiner keel, a longer rudder, a different mast, different genoa controls, etc..

Some things are just like they are...your boat was made to sail faster than the other same type boats, but it has many many limitations...

A Ford Focus will never be a Porsche, even if you put stickers and go fast stripes on the doors..

Now, change the suspensions, brakes, engine etc...It will do as a Porsche, go fast as one..BUT it will never be one...

You need to start investing heavily (I know believe me) to make the boat do what you want..THAT boat will not behave good in strong winds, its a low to moderate wind boat...that boat is just a regular fast cruiser, like a Dehler or a Grans Surprise, it will never be a Sinergia or a B&C...

And to be honest...investing in that boat to bring it to do what you want..might as well buy an old IMS off the Copa del Rey in Spain, and then you'll be driving the Porsche...
Sorry


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## sailingdog

Gui-

It isn't even Xuraax's boat... 



xuraax said:


> .....
> 
> * My other problem is that I do not own the boat so, of course, before playing about with other people's stuff one must be extra careful on what one is doing.
> *
> ...


----------



## xuraax

Thanks one and all for the many replies. 

However this thread is not about whether this boat is a good racer or not. That may well be the final conclusion when all things are checked and confirmed to be correctly set.

The thread is about adjusting the rig, and recently it had shifted into how to optimise the rig for higher winds. That is surely an interesting argument.

regards


----------



## Harvester

Great post, Giu!

Precisely I have a problem with the rigging and I was looking for an expert to help me fix it.

Only one suggestion, I am not acquainted with the cable measurements (1/4, 3/16, 5,16). Do you have at reach the equivalence in mm for you neighbours? (Well, I am not exactly your neighbour because I'm Catalan so we have Spain in between....  )

Thanks a lot!


----------



## Giulietta

Harvester said:


> Great post, Giu!
> 
> Precisely I have a problem with the rigging and I was looking for an expert to help me fix it.
> 
> Only one suggestion, I am not acquainted with the cable measurements (1/4, 3/16, 5,16). Do you have at reach the equivalence in mm for you neighbours? (Well, I am not exactly your neighbour because I'm Catalan so we have Spain in between....  )
> 
> Thanks a lot!


Actually the tables I have are in millimiters. But for the guys here at sailnet I had to covert from KN and Kg to Inches and Pounds.

Here is a tble I made in Excel and took a snap shot, that should make it clear for everyone in Inches and Millimiters, KN, Kg and Lbs.


----------



## sailingdog

Nicely done.


----------



## Harvester

Giulietta said:


> Actually the tables I have are in millimiters. But for the guys here at sailnet I had to covert from KN and Kg to Inches and Pounds.
> 
> Here is a tble I made in Excel and took a snap shot, that should make it clear for everyone in Inches and Millimiters, KN, Kg and Lbs.


Yuppi!
Double thanks! 
I'll be working on it this weekend.


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## TSOJOURNER

In order to check the lateral position of the mast use the main (or jib for fractional rig) halyard and swing it to the port and starboard rails.

Don't forget to sight up the mast to look for bends. The lower shrouds can be used to straighten some of the bends. Often times the lowers are set looser to allow for mast bend. In fact in some racing classes the lowers are adjusted according to the wind speed.


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## runner

Newby questions. How do you tension the shrouds on a three stay rig where the mast comes down after each use? How do you bend the mast with a three stay rig and no aft stay? The thin metal strip shrouds have to be disconnected to adust them. You place the mast thru the deck, connect the shrouds, connect the fore stay, pin the foot, and then you final tension the shrouds using the fore stay turnbuckle on my boat. There are upper turnbuckles on the upper ends of the flat metal strip shrouds. I could make balancing adjustments to balance the tension side to side with a ladder and the oak tree in the yard the way it is set up. Should the turn buckles be at the deck and the end that has to be taken loose to adjust be attached to the strap on the mast? Do you reverse them to get the adjustment made and then put them back as they were? 
How much fore stay tension do you use when you have a mast that uses the deck as a pivot point? 
How much rake is correct on a comet class boat with a shorter mast? It came adjusted for a foreward rake. 
Does sail type change the answers? I have old canvas sails. 

Sorry for all the questions, but I am trying to learn as much as I can before I do something really dumb from not knowing the correct procedures.


----------



## GaryHLucas

Giu,
There is something wrong with your statement that 1mm of stretch = 5% of breaking load. This has to be 1mm of stretch per 1 meter of length, or some other ratio. I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!


----------



## Giulietta

GaryHLucas said:


> Giu,
> There is something wrong with your statement that 1mm of stretch = 5% of breaking load. This has to be 1mm of stretch per 1 meter of length, or some other ratio. I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!


Maybe it was the way I wrote it.



Giulietta said:


> c) Now for the main shrouds, if you don't have a Loos, or are just a cheap person, you can use a measuring tape. I did for many years.
> 
> You will need *to attach a tape of at least 2 meters to the shroud*, so that the zero or the beginning of the tape starts at the turnbuckle.
> 
> The rule is simple each 1mm of stretch means 5% of the breaking load, and that is valid for *ANY CABLE IN A SHROUD*, no matter what the diameter is!!!


----------



## KeelHaulin

GaryHLucas said:


> I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!


Yes; that was why I did the calculation on page 3 to show what theoretical length would be needed to stretch a cable to 15% break strength. It's dependent on the pre-tensioned length of the wire (and type of metal); not diameter.

15% break strength on an 800' (type 316) cable would be to stretch it approx. 6 feet. (Not accounting for thermal expansion or weight); so depending on the type of wire you were probably at about 20% break strength or a bit higher.

Giu's rule-of-thumb will put approximately 20% breaking strength into the shroud if you stretch 1mm per meter of cable. So a mark at 1 meter should move up 1mm on a scale attached to the shroud swage. For 10% breaking strength stretch 1mm per 2 meter length measurement.


----------



## Giulietta

Keel, I am not going to argue this anymore.

You surely have heard about Selden masts, right?

Please allow me to redirect you to their shroud adusting manual.

PAge 30

PAge 31

PAge 39

I am sure your calculations are all correct and such..I got this this morning off the net by googling tension shrouds, and found this manual.

There are several more with the same instructions.


----------



## Valiente

I was rather pleased to find out that my motorsailer's 6 x 9 inch "tree stump" mast was in fact a Selden, so I purchased a Selden pole lift ring to fit in the handy grooves. Now, of course, I have to tap in holes for cheek blocks (or cut rectangular holes for sheeve boxes) to move the thing up and down.

I have a further question out of these Selden pages, though, Alex: See here?










Everyone I know tightens the turnbuckle with a screwdriver. Why a wrench/spanner?


----------



## Giulietta

Valiente said:


> Everyone I know tightens the turnbuckle with a screwdriver. Why a wrench/spanner?


I'll keep it simple...

That type of turnbuckles are designed to support tension forces only, and has very little torsion strenght, mainly because there are very little lateral efforts they need to support.....it's made that way when the turnbuckle is made, when the metalurgists make sure the grain of metal is more oblong, making it tension resistant, harder, but less resistant to lateral forces.

In using a screw driver, you are stressing the legs of the turnbuckle with lateral forces, (for which the piece was not designed for), and even twisting the turnbuckle legs, wich then get stressed, and the integrety of the intergranular structure gets compromised, possible causing it to fail at a later stage.

For this reason, the turnbuckle manufacturers make 2 flat surfaces, like a nut, to use a wrench, that will in turn provide rotational forces without stressing the legs of the turnbuckle.

Hope it was simple.

Alex


----------



## Valiente

Yes, that explains it perfectly, and I will change my habits accordingly.

Although I am lucky enough to have old Merriman turnbuckles in chromed bronze and they seem a little more _robust _than the current types.

This is Merriman "style":









They aren't made anymore, as far as I know.


----------



## KeelHaulin

Giulietta said:


> Keel, I am not going to argue this anymore.


Was not trying to argue anything Giu; I was simply trying to add some information to your excellent post of how to adjust your rig tension.

Since there was confusion on what your post was saying I tried to determine why it would be 1mm extension for 1 meter or 2 meters; but it is off by ~50%. The calculation is correct; so it must be a problem with the published breaking strengths. So I was doing some more research on 316 stainless and it turns out that the published breaking strengths must not be actual ultimate breaking loads; they seem to have a safety factor of 2 built in. The 15% breaking strength calculations I did earlier were based on the published breaking loads; while the Selden formula is based on the true Utimate Tensile Strength of stainless wire (actual failure strength).


----------



## obarut

I have an in-mast furling for main sail. Therefore when I bend the mast during sailing the furling system operation is adversly effected. Is it a good idea to bend such masts or to keep them straight is better?


----------



## tommays

Bending of the mast is usally done to adjust sail shape ,with a roller furling main you are generaly giving that up as a tradeoff to the convience of furling


----------



## windship

All good info but really...it's not that difficult to do.
Lay on your back, feet facing the bow, looking up the mast to see the straightness of it port to stbd. Adjust until straight with moderate tension on the shrouds or stays. Next lay on your back with your feet off the beam while looking up the side of the mast to check for bend for and aft. Adjust acordingly until straight with moderate tension on shrouds and stays...done. I've been doing it for 15 years this way.


----------



## captainmidnight

*older not always better*

[maybe robust, but they're also likely older than I am and due for replacement, cheap and easy compared to replacing entire rig, nothing lasts forever


----------



## HenryTully

*Rod Rig Tensioning*

Anyone,

I have NavTec rod rigging on my 40' boat. Should the lower shrouds have the same level of tension at rest as wire shrouds or should there be more tension? I noticed this summer that the lee shrouds were flopping around when we were sailing.

Hank Tully


----------



## knothead

HenryTully said:


> Anyone,
> 
> I have NavTec rod rigging on my 40' boat. Should the lower shrouds have the same level of tension at rest as wire shrouds or should there be more tension? I noticed this summer that the lee shrouds were flopping around when we were sailing.
> 
> Hank Tully


Usually, the uppers are tightest, next the intermediates and then the lowers. This can vary with the type of rig. A good rule of thumb is that the larger the diameter, the more tension.
Your lee shrouds, in my opinion, should not be flopping around.


----------



## lancelot9898

I used the folding method as Selden explained to tension my rig last year since the 1x19 wires were larger diameter than the standard tension gage available. It was easy to do and the boat now points better. Good explaination.

Another thing I did which may or may not be right is to replace the old spartite around the mast. It's keel steped and I was getting some leakage through the deck and when I went to replace the mast boot I saw that the original spartite(not sure if it wa spartite) was cracked and crumbling. I dug it all out and then just used the best silicone caulk that I could find to fill the gap. The silicon may not be as hard as the epoxy based spartite, but it does limit movement of the mast at the deck. Not sure if there is much movement anyway since the mast is thick walled. At the Annapolos boat show I asked the spartite people about this, but they really didn't have any good response. The one problem that I see is that the cure time for a thick ribbon of silicon to comletely cure might be excessive?? days..weeks ...months


----------



## Giulietta

BUMP for Lapworth


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## ggrizzard

*Found Merriman toggles*

There may be Merriman available at: defender's web site (Rules prohibit me from posting the site name!)


----------



## ggrizzard

Found Merriman toggles on defender's site


----------



## ggrizzard

anyone else with merriman turnbuckles?


----------



## ggrizzard

*Merriman anyone?*

Anyone else use merriman toggles?


----------



## TSOJOURNER

*Shroud length/tension problem*

For people still struggling with the length issue look carefully at the image posted before by "Valiente" at post # 61. (Sorry I'am not alowed to post images so I can not show the image myself)

At first I will say that I also was confused and could not believe what "Giulietta" was saying about this. Plus I had to agree with what "KeelHaulin" was saying about length of the shroud. 

Then I saw this image and everything became clear.  

If you look good at the tape measure in the drawing you will see it is attached, at the top of the tape measurer, to the shroud with adhesive tape. What this means is that you are indeed lengthening the whole shroud but only measuring the stretch over 2 meter.

If you keep this in mind the whole explanation makes sense.


----------



## Giulietta

YEs...exactly right...

Thanks for understanding


----------



## lancelot9898

Giulietta said:


> *
> 
> 2) Longitudinal Adjustment. (Rake)
> 
> (NOTE: this has to be done in a day with no wind with the boat perfectly horizontal, shift weight if you have to balance the boat).
> 
> Rake will help increase or decrease Weather helm. Aft Rake increases weather helm, improving pointing, forward rake does the opposite.
> 
> Normal rake is 1 to 2º degrees aft for cruiser boats and up to 4º deg aft for high performance racers.
> 
> a) Install a bucket with water under the boom by the mast.
> 
> b) Attach a heavy object to the main sail halyard and dip it the bucket but it should not touch the bottom of the bucket. (The bucket and water are used to dampen the swinging of the halyard.)
> 
> c) Measure P, which is the distance from the boom to the top of the mast.
> 
> d) Measure the distance from the halyard to the edge of the mast, at the gooseneck.
> 
> [
> 2) Mast Pre bend
> 
> Once the masts are where you want them to be, and before we tension the shrouds, we need to set the masts curvature, or pre-bend.
> 
> For this attach the halyard that was in the bucket so it ends at the mast foot.
> 
> Now adjust the baby stay and or forestays so that the belly of the mast goes forward. Takes a few tries.
> The max bend at rest should not exceed half of the mast diameter.
> 
> Have fun.*


*

Alex,

Still a little confused about mast rake and mast bend and how to put in one without effecting the other. I've seen the diagram showing the difference between the two so that is not what I'm questioning, just implementation of it with a mast head rig, a keel step mast with "spar-tite" around the mast at deck level, cutter rig with furler on the forestay(Pro Furl), bow spirit with bob stay, and heavy dispalcement cruiser. (A Tayana 37) Even with putting somewhere near 25% tension on the backstay, the mast remains vertical using the method of the halyard hanging from the mast head. It seems that in order to get aft mast rake, I would need to adjust the keel step such that the mast sits at an angle fore and aft using shims. If that is the case then there can be no adjustment to the mast rake once the mast is installed on the boat. Is my understanding correct on that point?

The other question is the tension in the forestay with furler. I did look for some way of accessing the wire like you suggested, but I can't locate anything in the Pro Furl. The only thing I can figure is to assume that whatever I put into the backstay gets transmitted to the forestay.

BTW Your videos are great!

DB on the Cheaspeake Bay*


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## northbay

Along this line but different. The tang fitting, the fitting that accepts the 
marina fork at the mast, how much movement should it have?

Bob SV Journey


----------



## tojaso

Ok...I just said to my wife, "You know, I think I can fix this rigging myself..." We had an after shroud break on the delivery along with a fore stay. The release in the tension caused the mast to shift now it leaks at the deck into the head.
The boat is a gaff rigged ketch and I am calling a rigger...HA Thank you for the info, I am not a moron, but this is beyond my current skill level.


----------



## sassafrass

nice topic and great info...

i race in one design keel boats some of the time. rig tune is paramount to sucess. so i thought i would chime in a few fine points for those looking for them (like the comment on how to tune your rig for 20 knots).

sailboats have generally two modes upwind. seeking more power, and seeking less power, with a small happy medium in there. there are of course things we do with strings to help with this, however, mast tune is more significant, that is like a coarse adjustment, the strings we pull the fine adjustments.

i would also side with the disclaimers that have been mentioned, but you may want to consider going too much with an adjustment. that is go too far, far enough that you will know it is too far (performance will suffer). then you will know it is somewhere between those values (of too little/too much).

all of this is for uphill travel...

mast position in the boat (fore and aft) is critical. every boat is different in this regard. talk to other people with your boat and see what they have found out. with the butt, partners and forestay length you can control mast rake. if you have too much weather helm with mast rake right, the mast needs to move forward. not enough, mast needs to move aft. this is assuming your are trimming everything right. highier winds we use less rake, that is we shorten the forestay for the same butt position. other boats move the butt around. both work, but forestay length changes other things as well, and i think is generally easier. i don't know the math on degrees, as we measure the forestay length for the adjustment, but i would suspect we vary the rake by several degrees.

optimizing for light air. forstay sag is good in light air as you are trying for max power. you can try the same on the luff of your main by letting it sag off. how much, well you can try too much and then tighten up from there. too much sag will break/bend your mast. don't send me the bill. i would think somewhere around one to one and half mast diameters would be ok. this is what we use. as the wind builds and the boat is not needing as much power you can bring the mast in line. you do this by adjusting the lower/intermediate shrouds. 

for high winds, the opposite is true. you will want no forestay sag (impossible), shorter forestay, less rake (butt aft, wedge partners forward). you will want your mast straight side to side, with more prebend. ideally, you will want the top of the mast to fall off some. fractional rigs do this better.

you can adjust some of this with a backstay adjuster, but really you need to get up there and adjust your forestay length/butt/parnter position to optimize your boat for any particular windspeed. most people in crusing, even racing boats will not play with there upper/intermediates/lowers at all. they have a set it and forget it attitude, especially with discontinous rigs. there is nothing wrong with that, in fact a lot of sense. tune for midrange and use other adjustments to keep the boat on its feet/use the engine if there is not enough wind.

downhill is different of course and mast tune is not as critical. you will want to undo as much rake and prebend as possible with your set up. having the mast tilt forward is best. you cannot do this with spartite, but you can with removable fore and aft wedges.

best of luck...
tom


----------



## TundraDown

*How to Center your Rig*

Here is a link to UK-Halsey's video on centering the mast. it makes good, simple sense to me.

How to Center your Rig:

Login - UK-Halsey Sailmakers

George


----------



## aibuiltpc

What a great Sticky. 

Just wanted to add a tool that I recently picked up from Lowes. I havent tested it yet but as per the original post stating the importance of a level boat to start with I think this might help and actually picked it up prior to reading this. 

It is a Ball level. If you are not on level ground you can figure and mark the level horizontaly then compensate for vertical and even check the degree of angle on the rigging from port to starboard and make certain they are equal .


----------



## TSOJOURNER

Hey everyone. I'm new here (as I'm sure you can tell). As we are talking gear, what tools do you think makeup the perfect small toolbox? What tools do you rely on more than others?

I have several tool boxes for sailing, packed full of random things, so i thought it would be good to see what is absolutley essential.


----------



## Skipper995

#1 thing for EVERY tool box is a roll of duct tape. There are few things that this stuff can't fix or help fix. Just wish I had invented it!!!


----------



## Nodiaphoresis

OK, I have done some homework. I have read and then skimmed these posts, learned a couple of new words and will be able to impress my big boat friends. I just bought, however, a sweet little 10' dinghy in an auction. It is not a Minto. It is fiberglas with teak trim. When I unwrapped the wood mast and sail I found a gaff rig. I then noticed a number of brass (bronze) rings, jam cleats and holes scattered throughout. I have found a drawing of a gaff rigged larger dinghy on the internet, but I cannot tell some of the drawn lines are edges or lines (for attaching things). Does anyone know of a source of a rigging diagram for one or more of these boats?

I shall send a photo of the boat when I have cleaned it, oiled it, etc. I would also like to know who built it and its name if any. I heard a rumor during the auction that it was built in England.

Thanks,

Nodiaphoresis


----------



## PCP777

Nice, marking


----------



## Leftbrainstuff

*propellor hat approved*

Nice technical rig tuning post.

Just to clarify a few basic engineering principles.

Engineering strain is dimensionless. So multiply by length to calculate actual stretch to achieve a certain preload.

Strain is for the elastic range of the material. Cross sectional area or wire diameter is not a factor.

Preload by strain is the most accurate and repeatable method of tensioning (preloading). We also use it for bolts, pin joints etc.

The whole purpose of preload is to avoid unloading the rigging under any conditions. You want the minimum preload your rig can accept. Any more is just compression loading the mast and lowers the buckling stability of the mast.

Ideally you want to know how much your rig will move under all conditions. This is impractical to do on an actual vessel. So rules of thumb apply with caution.


----------



## albrazzi

Lets try and start this back up. I know its not my thread but can we agree to not spend too much time discussing all aspects of stretch and such. Lets assume there is a Loos type guage available. I have some basic questions and some from the old thread not answered because (my opinion) too much time was spent on digression. 

It was questioned early on how to get the desired bend after the rake is set. Its my contention that backstay and either Baby stay of forward shrouds and a bendy mast (not all are) are the tools. Lets talk about the methods and application.

I'm currently sailing a CS 30 Fin keel, spade rudder with a very small partial skeg. Baby stay and inline shrouds, Selden mast. No Backstay adjustment although I would like to have some.


----------



## aloof

Keel stepped? For and aft lower shrouds? And you say the backstay is not adjustable. But there is a turnbuckle, right?

I would think rake and bend are setup together...


----------



## albrazzi

aloof said:


> Keel stepped? For and aft lower shrouds? And you say the backstay is not adjustable. But there is a turnbuckle, right?
> 
> I would think rake and bend are setup together...


Keel stepped w/inline shrouds. No apparent adjustment on the step. Don't know that I need adjustment there. It was not clear that bend and rake are set together. I would think rake is fore aft stay adjustable and bend is created with backstay tightening with either a Babystay or a forward lower shroud helping the bend get started.

Backstay is adjustable of course but not underway.


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## aloof

The bend will be induced at the partners. If the masthead is where you want it, rake, then adjusting the mast forward in the partners will induce some bend. I wouldn't use the baby stay as the principal way to induce bend but rather the combination of the mast step, partners, forestay, and backstay. The baby is more to prevent pumping in rough weather...for stability...in my usage.

If the mast step is not adjustable then the partners must be adjusted, and vice versa. My current setting is a bit weird because the partners has the lower third of the mast slightly bent forward. Not much but just enough to bother my eye when riding up in the dinghy. Something got goofed up last time the rigging was replaced as there is an extra toggle in the forestay, too. Other than the annoying lack of aesthetics everything is perfect.


----------



## Faster

Is the baby stay adjustable? With in line shrouds it's the only way to induce bend unless you've got a very powerful (hydraulic) back stay and/or a bendy rig. If the step is adjustable then you might be able to prebend by using the partners as a 'fulcrum' as you pull the masthead aft to set rake. 

The luff curve of your main is going to dictate the amount of prebend you want/need.


----------



## albrazzi

aloof said:


> The bend will be induced at the partners. If the masthead is where you want it, rake, then adjusting the mast forward in the partners will induce some bend. I wouldn't use the baby stay as the principal way to induce bend but rather the combination of the mast step, partners, forestay, and backstay. The baby is more to prevent pumping in rough weather...for stability...in my usage.
> 
> If the mast step is not adjustable then the partners must be adjusted, and vice versa. My current setting is a bit weird because the partners has the lower third of the mast slightly bent forward. Not much but just enough to bother my eye when riding up in the dinghy. Something got goofed up last time the rigging was replaced as there is an extra toggle in the forestay, too. Other than the annoying lack of aesthetics everything is perfect.


I have some work to do, after running out of adjustment on the backstay, I took a couple of turns on the headstay (furler) now I need to start from the beginning and measure the rake if the headstay needs to go out then the Backstay may be too long.
I need to see what the arrangement is on the partners. I could pull the boot up and see how its assembled but I'm not ready to pull the mast right now and the boot is leaking just a bit and I'm kind of afraid of making it worse.


----------



## albrazzi

Faster said:


> Is the baby stay adjustable? With in line shrouds it's the only way to induce bend unless you've got a very powerful (hydraulic) back stay and/or a bendy rig. If the step is adjustable then you might be able to prebend by using the partners as a 'fulcrum' as you pull the masthead aft to set rake.
> 
> The luff curve of your main is going to dictate the amount of prebend you want/need.


It has a turnbuckle, but not adjustable underway like C&C does with the short track to pull it out and tension.
My view is a downwind tension on the headstay and a straight mast (with the right rake), then get the bend with a backstay adjuster enough to flatten the Main. A new Mainsail is a need not a want right now and I want to work all the rig geometry out so I can get the cut right.


----------



## aloof

You can easily check if the partners are reasonable. Good chance they are. Slacken all the stays. If there are fire/aft lower shrouds slacken them too, but count the turns. Observe the mast straightness...just for a starting point. It should be fairly straight. Then apply some backstay tension while easing the forestay until some moderate bend is induced. Is the rake reasonable? If all looks reasonable then the partners and step are in a good place. Tighten everything back up in such a way that the masthead and bend and rake don't change much. If all is not good with just a little backstay tension then something will need to be done at the partners or step. If nothing is done the mast will not have a continuous bend from step to head but two bends. That cannot be good.

In a perfect world the mast is tuned without the fore and aft partners in place. When tuned they are inserted without changing the mast position. That's my method anyway. The step is adjusted to keep the mast reasonably centered in the partners, or perhaps for some other effect...such as my predicament as described above.


----------



## albrazzi

aloof said:


> You can easily check if the partners are reasonable. Good chance they are. Slacken all the stays. If there are fire/aft lower shrouds slacken them too, but count the turns. Observe the mast straightness...just for a starting point. It should be fairly straight. Then apply some backstay tension while easing the forestay until some moderate bend is induced. Is the rake reasonable? If all looks reasonable then the partners and step are in a good place. Tighten everything back up in such a way that the masthead and bend and rake don't change much. If all is not good with just a little backstay tension then something will need to be done at the partners or step. If nothing is done the mast will not have a continuous bend from step to head but two bends. That cannot be good.
> 
> In a perfect world the mast is tuned without the fore and aft partners in place. When tuned they are inserted without changing the mast position. That's my method anyway. The step is adjusted to keep the mast reasonably centered in the partners, or perhaps for some other effect...such as my predicament as described above.


Do you use an adjustable backstay or just set and forget it. Do you race, I do some clubbing and a Bay race or two but may want to do a lot more if I get my rig right.


----------



## aloof

My backstay is hydraulic. On this boat the backstay adjustment is mostly for headstay tension. Pumping it on does bend the mast, of course, but that bend is usually mostly removed with the runners to give the main some shape. But whatever it takes to get the job done...that's my principal rule. I race and cruise. Cruising is not lazy for me. Always optimizing performance and comfort.

I have the mast setup so that with the backstay off, baby off, runners off, not sailing, there is about 2 inches of prebend in the 60 feet of mast above the deck. The aluminum section is 8" deep. Then while sailing I adjust things as appropriate. 2" of bend gives a nice full main luff. No bend makes the luff a little too loose. More bend, maybe 8", a full diameter, flattens the main nicely, like a door, more so at the top. The conservative limit is 1.5 diameters, 12", of bend. I have the hydraulic cylinder set so that with no runners on I cannot go much past that amount of bend.

I went up in the bosun chair and measured the static bend at three places. The sailmaker uses those measurements for the sail. It is a truly beautiful thing when done right.

The babystay is really just there to hold on to while on the foredeck  It doesn't seem to do anything for bending. My spar builder agrees. It is rather an old fashioned thing, however is handy when bashing thru seas. Especially with bare poles or no wind.


----------



## albrazzi

aloof said:


> My backstay is hydraulic. On this boat the backstay adjustment is mostly for headstay tension. Pumping it on does bend the mast, of course, but that bend is usually mostly removed with the runners to give the main some shape. But whatever it takes to get the job done...that's my principal rule. I race and cruise. Cruising is not lazy for me. Always optimizing performance and comfort.
> 
> I have the mast setup so that with the backstay off, baby off, runners off, not sailing, there is about 2 inches of prebend in the 60 feet of mast above the deck. The aluminum section is 8" deep. Then while sailing I adjust things as appropriate. 2" of bend gives a nice full main luff. No bend makes the luff a little too loose. More bend, maybe 8", a full diameter, flattens the main nicely, like a door, more so at the top. The conservative limit is 1.5 diameters, 12", of bend. I have the hydraulic cylinder set so that with no runners on I cannot go much past that amount of bend.
> 
> I went up in the bosun chair and measured the static bend at three places. The sailmaker uses those measurements for the sail. It is a truly beautiful thing when done right.
> 
> The babystay is really just there to hold on to while on the foredeck  It doesn't seem to do anything for bending. My spar builder agrees. It is rather an old fashioned thing, however is handy when bashing thru seas. Especially with bare poles or no wind.


Are your stays inline or spread for some aft support. I suppose the mast just wants to bend that way? so pulling on it just makes it bend. I've also heard the Baby Stay helps keep the mast in one piece with heavy spinnaker loads. Yea or nay on that.


----------



## aloof

Triple inline spreaders. Single lowers. The chainplates are slightly aft of the mast center as are the actual spreader tips. That may help the prebend. But I don't know...never asked. The mast bends because the partners push it forward at deck level against the step and backstay. It's a bendy mast section, too.

Baby stay might help with spinnaker pole loads, but the "chicken stays" are specifically for that. Actually a check stay, they run from head level on the mast to the foredeck. Such forces are unlikely except in absolutely crazy pole-forward racing. Especially on boats that load up...IOR...instead of surfing the loads away. Or if the pole and sail tend to get stuffed into the sea.


----------



## hellosailor

In the US, you can buy a car, own a car, register a car, and get a driver's license, without any knowledge of how to change a spare tire. (Well duh, you'd obviously call the road club or buy a new car, wouldn't you?)

In France, I'm told that if you can't show proficiency at how to change a spare tire or spark plug, you don't get a license at all. At least, it was that way circa 1970 when my friend had to do that.)

So, rigging? So what, some shmuck buys a boat and rig collapses. With any luck, all involved parties drown, the lawyers are not involved, and the crabs get to eat. As the gods intended them to.

I fail to see a problem, except for failing to feed the crabs.


----------



## albrazzi

Looks like the keel step is the key to bending a mast, I get it now. Looks like a good start back up on a good discussion. Thanks for the enlightenment. Like I said I have a lot to do. At least this year I can make the rig a priority.


----------



## albrazzi

hellosailor said:


> In the US, you can buy a car, own a car, register a car, and get a driver's license, without any knowledge of how to change a spare tire. (Well duh, you'd obviously call the road club or buy a new car, wouldn't you?)
> 
> In France, I'm told that if you can't show proficiency at how to change a spare tire or spark plug, you don't get a license at all. At least, it was that way circa 1970 when my friend had to do that.)
> 
> So, rigging? So what, some shmuck buys a boat and rig collapses. With any luck, all involved parties drown, the lawyers are not involved, and the crabs get to eat. As the gods intended them to.
> 
> I fail to see a problem, except for failing to feed the crabs.


I cant tell what you are trying to say here. I'm trying to reopen a sticky on Rig set-up not asking a question on whether or not to I should replace my 25 year old rusty stays.
Certainly I don't want to stifle anyone's free speech, I was just hoping to keep it on topic.


----------



## Bleemus

*Re: Adjusting Your Rig, step by step.*

The fact that your spreaders tips and chainplates are slightly behind mast center will cause mast bend through shroud tension.

Sent from my iPad using Tapatalk


----------



## Faster

Often times the baby stay is there simply to reduce/eliminate mast pumping in certain conditions, esp if it's non adjustable on the fly. Such 'fixed' babystays are not sail shape controls.


----------



## albrazzi

Faster said:


> Often times the baby stay is there simply to reduce/eliminate mast pumping in certain conditions, esp if it's non adjustable on the fly. Such 'fixed' babystays are not sail shape controls.


Not even considering it holds the mast forward as you tension the backstay? Like I have said I haven't looked at the deck penetration for construction. What I'm reading as the "partners" is (I assume) the mast being fixed to the deck in some way. Is that correct? Could a Babystay boat use the Babystay connecting point as a "pivot" if you will, and the Mast floats in the deck opening or do I have some sort of hard sealant in that area I'm not seeing.
Again CS 30 with Selden mast. No indication or reason to believe all is not original.


----------



## Faster

albrazzi said:


> Not even considering it holds the mast forward as you tension the backstay? Like I have said I haven't looked at the deck penetration for construction. What I'm reading as the "partners" is (I assume) the mast being fixed to the deck in some way. Is that correct? Could a Babystay boat use the Babystay connecting point as a "pivot" if you will, and the Mast floats in the deck opening or do I have some sort of hard sealant in that area I'm not seeing.
> Again CS 30 with Selden mast. No indication or reason to believe all is not original.


"Partners" is where the mast passes through the deck opening.. usually wedges are placed here prior to the boot to hold the mast in the right position within the hole. "Spartite" is a pourable rubber compound that sets up kind of hard and is often used in place of wedges (which can occasionally shake loose in the wilder going)

Exactly where you wedge the mast in the partners (depending on clearance space) can help determine rake and/or prebend. It would be very odd to see a setup where the partners were allowed to 'float'.

Yes, the baby stay can be used to induce some forward mast bend, and indeed the adjustable types like C&C liked to use did just that as long as you have in-line shrouds. The minute you triangulate with swept spreaders/aft shrouds you lose that adjustability.

When adjusting the backstay usually the main objective is to tension the forestay to reduce luff sag. If the backstay is very powerful, you can induce compression bending in the mast - if the mast is allowed to bend too much, you lose transferring that force to the forestay. Limiting mast bend is a checkstay's job, pretty much the opposite action of a babystay.

Anyhow, on your boat sounds like you want to set the babystay to give you some 'prebend'.. and how you leave it will depend on your mainsail's shape.


----------



## albrazzi

Thanks for the explanation, I might lift my Mast boot just for a look see. It looks like the intent of my Babystay is to help create the arc as the mast bends so the stress is not all on the partners.


----------



## Untrained

old thread, but relevant to me.
I'm a newbie to sailing, learning by doing and reading. First boat 35' masthead sloop, 50' mast ,swept back spreaders (2 of them). 
I can grab my roller furled genoa and move it 6-8" in any direction. I hadn't noticed it until now.
How much should I be able to move it by hand? I bought a loos tension gauge but i'd have to remove the furling setup to use it on my headstay (I think).
Any advice?


----------



## overbored

The forestay length sets the mast rake, fore and aft position on the mast, which is used to balance the helm, weather or lee helm. the backstay sets the forestay tension for the amount of forestay sag. the jib is cut for a given forestay sag. you don't need to use a Loos on the forestay. the Loos is used to set up the rigging at the dock and then you go sailing to to make final adjustments to the rig for the conditions and the sails.


----------



## albrazzi

Untrained said:


> old thread, but relevant to me.
> I'm a newbie to sailing, learning by doing and reading. First boat 35' masthead sloop, 50' mast ,swept back spreaders (2 of them).
> I can grab my roller furled genoa and move it 6-8" in any direction. I hadn't noticed it until now.
> How much should I be able to move it by hand? I bought a loos tension gauge but i'd have to remove the furling setup to use it on my headstay (I think).
> Any advice?


Welcome to the discussion, I am learning as well but recent upgrades have made me smarter than last year:angel

That's too much headstay sag for anything other than off wind points of sail. Any attempt to go close hauled in all but the lightest of airs will push your bow over and just over power the boat. Do you have a tension guage? and with swept stays you need to set the backstay first to set the headstay then look at the stays (shrouds) get or borrow a LOOS or equivalent, once you use it a while you can tell by feel.
Do you have a backstay adjuster, not a must have, but they are nice if you're doing any Racing even casually.
Basically you set everything for moderate conditions without an adjustable, and an adjustable backstay lets you loosen the rig as well as tighten it up for heavy upwind.


----------



## overbored

I doubt you have swept back spreaders on a Ericson 35-3 you do have the aft lower shrouds if that is what you are reefing to as swept back. Erickson yachts.org has some of the original rig tuning docs that might be helpful.


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## RichH

QUOTE - "How much should I be able to move it by hand? I bought a loos tension gauge but i'd have to remove the furling setup to use it on my headstay (I think).
Any advice?"

Pushing or pulling on any loaded wire at 90° can impart 'bodacious' loads along the length of that wire. 
If the angle to the top of your mast with your forestay is visually close the angle that backstay makes with the top of the mast .... your backstay tension will be close to the tension in the forestay .... when you are initially setting up your 'basic' (at the dock, etc.) rig tensions.

The real tension in that forestay wire depends on how much 'curvature' was cut into the luff of your jib/genoa youre using. Most jibs/genoas are cut for a normal boat sailing (beating to windward) in 12-15kts. of wind. If you want optimal precision for forestay (approx. backstay) tension ... no gage needed, go here: http://www.ftp.tognews.com/GoogleFiles/Matching Luff Hollow.pdf

Edit/Add Note: this article was written for cutter rig jockeys; so to make this article applicable to sloop drivers, simply use the word 'forestay' in place of 'headstay'.


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## Untrained

Overbored, yep , you're right. Swept back stays go much farther back than mine. Thanks for the correction.
Rich, that's a good article, but with a roller furled Genoa, I don't think it's applicable. The info is appreciated.


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## Untrained

Albrazzi, Thank you also. Good info.


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## overbored

Untrained said:


> Overbored, yep , you're right. Swept back stays go much farther back than mine. Thanks for the correction.
> Rich, that's a good article, but with a roller furled Genoa, I don't think it's applicable. The info is appreciated.


Really does not matter if roller furled or not , luff curve works the same way


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## Untrained

overbored said:


> Really does not matter if roller furled or not , luff curve works the same way


now i'm really confused. Luff is the front of the genoa which is fed into a slot on my roller furler. isn't it?
So, how..... I really not sure if I want to know at this point. LOL Maybe it's too advanced for where I am right now.

OK, I had to re read the article linked. I understand now. 
Thanks again for setting me straight.


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## RichH

Untrained said:


> Rich, that's a good article, but with a roller furled Genoa, I don't think it's applicable. The info is appreciated.


Its most definitely applicable with ALL roller furling-reefing gear as well as tuff-luff and hanked-on. The correct tension of the forestay or (headstay) is responsible for the shape of the luff, etc.

My article is based on 'messing about' with the top-level super-sailors of the 70s & 80s .... no 'guessing' involved. 
Try it, you may like it. ;-)


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## Untrained

RichH said:


> Its most definitely applicable with ALL roller furling-reefing gear as well as tuff-luff and hanked-on. The correct tension of the forestay or (headstay) is responsible for the shape of the luff, etc.
> 
> My article is based on 'messing about' with the top-level super-sailors of the 70s & 80s .... no 'guessing' involved.
> Try it, you may like it. ;-)


 Rich, 
Yes , as I said in my post. After re reading the article it does make
sense to me.
Thanks for sharing your knowledge. It is appreciated.
:2 boat:


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## RichH

Untrained said:


> Rich,
> Yes , as I said in my post. After re reading the article it does make
> sense to me.
> Thanks for sharing your knowledge. It is appreciated.
> :2 boat:


HAHA ... that wasnt my knowledge, just quoting from others from my past.

Thanks for the thanks, much appreciated.


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## Samw90

Love the info here. Thanks!


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