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post #101 of 107 Old 04-05-2012 Thread Starter
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Re: Dynamic tuning of rig

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Originally Posted by DougSabbag View Post
This is excellent / valuable information! I can't wait to close on our CT 56 in July and utilize all the great information here!

I sure do want to learn how to properly tune my rig. My previous / haphazard methods, were proven to have a down side....

I used to just pull on the shrouds / stays, at the dock, and adjust them to "feel" equally tight. That was all, and surprise, surprise, considering the ramifications, that was not enough.

Thank you very much gentlemen!
Good luck on your new boat. I'm sure the days are dragging while you wait.
Just to reiterate. It seems unlikely that rig tuning even if not perfect would be the major cause of chain plates failing.
The real lesson is that any stainless chain plate that is over 10 years old and certainly over 20 years old could likely be work hardened and even if it looks perfect and polishes beautifully should be considered for replacement.
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post #102 of 107 Old 04-06-2012
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Re: The more I learn, the less I know!

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One thing I think most of us could easily over tighten any rig even with just hand tools, so I would not use that as an indicator.
To be fair, he did emphasize SMALL hand tools.

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The other thing I don't understand is why you would want slack on the lee ward shrouds. Would it not be best if all shrouds never went to 0 tension that way the shroud would not see cyclic loads that would potentially lead to fatigue failure? I have heard of long distance sailors tyeing bungees cord around the leeward shrouds to prevent fatigue failure (from the shroud swinging around for extended periods). Anyone know how say a volvo 60 is tuned in the around the world volvo race?
I assume that tightening the rig so that it didn't go slack on Leeward in high wind would require too much constant stress on the rig and boat. The bungee trick certainly wouldn't hurt though. I'm going to tune using the method I suggested in post 97, and will report back on the gage tensions it develops. Should be interesting. Using Dedekam's stretch method worked well as far a boat performance, but read high on the tension Gage. On the other hand, the Leeward shrouds would still go slack in high winds. Do your shrouds never go slack?

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Finally, to become a professional rigger /tuner what do you need to do? Go to college? Pass a test? Get a license? Rig and tune 1000 boats and not lose a rig at sea? WTH is a professional rigger? Could any of us hang a shingle and call ourselves a professional rigger?
As a Union Journeyman Carpenter with over 30 years in the trade , I can assure you that both the Union and Journeyman labels don't mean s**t! Worse yet, I have worked for several licensed Contractors who couldn't frame a wall to save their life, much less know if the job was being performed properly (and many "Inspectors" don't know much more)! So...given that the marine repair industry is less regulated than the building industry......
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Last edited by L124C; 04-06-2012 at 04:00 AM.
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post #103 of 107 Old 04-06-2012
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Re: The more I learn, the less I know!

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I think most riggers go through a (rather informal) apprenticeship and learn on the job from a (hopefully) skilled experienced person. I don't know of any official accreditation body (like SAMS for surveyors, for instance) but maybe Knothead will weigh in with better information.

I suppose any of us could hang a shingle as you say.. but be sure to have good 'mal-rigging insurance'!
This was my thought on it as well.

I was going to pick up a part time job at a busy seasonal marina last year and one of the job listings was "Rigger's Apprentice". There was a waiting list for it too, but from the description it seemed like working with the master rigger was something that was highly sought after.

As for "Dynamic Rigging" I always thought that pertained to systems aboard racing boats that allowed you to tune just about everything in the standing rigging while actually racing.

My dad raced Etchell 22s for a long time and spent a ton of money on these particular shroud turnbuckles that even under heavy load could be tuned quite dramatically by hand with ease. Everything on that boat could be tinkered with under sail in some fashion.
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post #104 of 107 Old 04-06-2012
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Re: The more I learn, the less I know!

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I have heard of long distance sailors tyeing bungees cord around the leeward shrouds to prevent fatigue failure (from the shroud swinging around for extended periods). Anyone know how say a Volvo 60 is tuned in the around the world Volvo race?
I would be more interested (for my 30 year old Keel Boat) in knowing what cruisers in similar boats do. I think the Volvo boats are high Tech with lots of carbon fiber, and technology light years away from my stout little "yacht".
A guy posted on the Yankee 30 Owners site, asking technical questions about tuning for different conditions and points of sail. Apparently, he came from a racing background with spindly, very tunable rigs. Another owner responded: "Think of the mast on your Yankee as a telephone pole"....
So, while a lot of the concepts are similar, I think it's important to compare
Apples with Apples. Still think the bungee's a good idea for extended distances for any rig. Thanks for that!
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post #105 of 107 Old 04-06-2012
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Re: The more I learn, the less I know!

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To be fair, he did emphasize SMALL hand tools.


I assume that tightening the rig so that it didn't go slack on Leeward in high wind would require too much constant stress on the rig and boat. The bungee trick certainly wouldn't hurt though. I'm going to tune using the method I suggested in post 97, and will report back on the gage tensions it develops. Should be interesting. Using Dedekam's stretch method worked well as far a boat performance, but read high on the tension Gage. On the other hand, the Leeward shrouds would still go slack in high winds. Do your shrouds never go slack?


As a Union Journeyman Carpenter with over 30 years in the trade , I can assure you that both the Union and Journeyman labels don't mean s**t! Worse yet, I have worked for several licensed Contractors who couldn't frame a wall to save their life, much less know if the job was being performed properly (and many "Inspectors" don't know much more)! So...given that the marine repair industry is less regulated than the building industry......

Do your shrouds never go slack?
In 20 knots or more wind my lee shrouds do go slack, but not by much. I would say they have near 0 load, but they are not swinging around. What I did (at the dock) is tuned my cap shrouds to 12%, lowers at 8% and backstay at 20% (the previous owner had it set to 20% so I just left it at that). On sailing everything looked good so I just left it at that. As others have stated, probably best to keep maximum load below 30% to fend off fatigue failures (most references seem to say go to 15% maximum tension on cap shrouds). I am thinking maybe I should back off the backstay as the forestay tension is probably around 25% at the dock (based on geometry calcs, since I cannot actually measure the tension due to furling jib). I would be concerned if my lee shrouds were swinging around a lot in a stiff breeze. Seems this could lead to fatigue failure very rapidly at the junction of a swaged or mechanical fitting and the wire.

A friend works as a "Rigger" for movie sets and I was talking with him how he got trained- he says basically on the job. Sounds similar to boat riggers. The two jobs have a lot in common. He is even giving me some advice on using a climbing harness to go aloft.
Regards

Last edited by casey1999; 04-06-2012 at 01:27 PM.
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post #106 of 107 Old 04-09-2012
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It worked!

Tuned under sail using the method I mentioned in #97. When I returned, I mesured the tensions in Cap shrouds. Both match (980 lbs) and are just below the initial tensions recommended by Loose for 9/32 rigging (1050). While tuning, I thought that I could have eliminated some more slack with another turn on the turnbuckles, but wanted to verify the tensions first. So...the system seems to work nicely.
Here is a link to the same method for J 22's, suggesting they "lose the gauge". In any case, it's nice to know both methods seem to produce similar results.
Thoughts on Tuning - Lose that Tension Gauge!
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post #107 of 107 Old 04-09-2012
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Re: It worked!

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Tuned under sail using the method I mentioned in #97. When I returned, I mesured the tensions in Cap shrouds. Both match (980 lbs) and are just below the initial tensions recommended by Loose for 9/32 rigging (1050). While tuning, I thought that I could have eliminated some more slack with another turn on the turnbuckles, but wanted to verify the tensions first. So...the system seems to work nicely.
Here is a link to the same method for J 22's, suggesting they "lose the gauge". In any case, it's nice to know both methods seem to produce similar results.
Thoughts on Tuning - Lose that Tension Gauge!
When I go to the link some of the number (number of turns and tensioin) show up as a square. Do you know why?
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