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-   -   Dynamic tuning of rig (http://www.sailnet.com/forums/seamanship-navigation/82959-dynamic-tuning-rig.html)

davidpm 01-21-2012 07:36 PM

Dynamic tuning of rig
 
DougSeabag mentioned that a major lesson he learned from his last boat was the importance of dynamic tuning of the rig.

Welcome back Doug
"2. Tune your rig. :-) What I had no knowledge of was that it HAS to be "dynamically tuned". When we stepped our main mast about 10 months before we headed East, without having dynamically tuned it after that, in effect, I did a lot more damage to our boat than if I hadn't stepped it at all.

We had 2 completely different rigger "companies" providing our out and in needs, but neither one mentioned the need to dynamically tune the rig.
One rigger was from West Marine, and the other was the best one in Fort Lauderdale: Nance & Underwood. Both had / have decades of experience and seemed to know their stuff. Which I still don't question; but, perhaps I didn't ask the right question, or something, but now I know, and am therefore sharing the mantra: Dynamically tune your rig."


The way I understand it dynamic tuning is done under sail in varying conditions. If so at $100 per hour this could easily cost one or two thousand dollars. I believe most sailors even racers do their own dynamic tuning.

Doug I would like to hear from you on this subject. Specifically why you now see this as so important and if you believe you could have done it yourself or would you get professional help?

Who dynamically tunes their rig? How do they do it and how important is it?

Siamese 01-21-2012 07:46 PM

I do the rig on my Catalina 309. Start by tensioning everything to 15% of breaking strength, followed by tweeking it under sail. Not super nit-picky about it, but like the idea of it being done right.

How important is it? From a safety standpoint, it's good to know that the rig is going to be at its max for strength. From a performance standpoint, it sure makes her point, as compared to the slack job that the dealer did.

WDS123 01-21-2012 09:36 PM

I have raced OD keelboats for a very long time and never heard of dynamic tuning - some of the Boats I raced were exceedingly finicky about rig tuning, but we always just called it tuning the rig.

Can anyone define dynamic tuning ?

Faster 01-21-2012 09:44 PM

I'm guessing that this is referring to the tuning adjustments made under sail after initially putting the mast in column and setting prebend.. but I've not heard that specific term before either. A google search does not turn up any direct references to such a term.

All we've done is set up the mast reasonably at the dock, then go sailing and observe any sag or lift in the column of the spar when hard on the wind.. observe both tacks, make some judgements on whether the top is sagging off excessively or if the mast is being 'held high' or allowed to sag at the spreaders and then adjust the respective shrouds accordingly. We always made the adjustments on the unloaded (lee) side and then tacked back to recheck.

WDS123 01-21-2012 10:16 PM

That what I was guessing, but there is always the chance some clever fellow has discovered some new trick.

davidpm 01-21-2012 11:04 PM

I'm waiting for Doug to weigh in as he mentioned that the tuning of of his last boat, or lack their off caused a lot of trouble.

L124C 01-22-2012 03:24 AM

I highly recommend a little book "Sail & Rig Tuning" by Ivan Dedekam. Think it will cover all you questions. He shows how to tune your rig and fine tune it under sail which he cleverly calls "Tuning under sail". In addition, Dedekam writes simply and concisely. I've picked up the book "Riggers Apprentice" a couple of times and put it down promptly when my head started hurting! Tunning is certainly important, but is not Rocket Science IMHO!
BTW, this thread probably should be posted in Gear and Maintenance, not Seamanship.

CorvetteGuy 01-22-2012 07:46 AM

The same is done seasonaly when we step our mast, first it is snug into place followed by a tune up sail, A quick look up the mast to look for any undesireable bends, the stays are then tweeked on the leeward side and locked into place for the season. Ive tried to use the stay tention tool but the results I got did not seem right. so now its done by eye,feel and experiance.

Dog Ship 01-22-2012 08:39 AM

I have tuned many boats the exact same way Faster has by tacking back and forth, but once the shrouds are tensioned thats it.
I think the term dynamic tuning is referring to a backstay tensioner or a jackstay, as you can make substantial adjustments easily while on the fly.
If not then I have no idea.

CaptainForce 01-22-2012 09:09 AM

Just by the denotation of the term, dynamic, I would expect that dynamic tuning would be adjusting the rig differently as conditions change; however, the earlier posts suggests that this is just referring to tuning under sail and not sitting at the dock.


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