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Discussion Starter · #1 · (Edited)
Hi All,

This question is for you who have experience tweaking standing rigging. The rigging was "dock tuned" by a pro rigger. I went out and had some wind this weekend and hope I finished the tuning correctly.

1st day we only had enough wind so that no matter how tight I pulled the sails in, we could only get a max of 12-15 degrees of list. I was clearly able to see the mast top leaning to leeward along with the slack lower shrouds on the leeward side. Lightened the cap shrouds so I had a straight pole and tightened the lowers hand tight to remove the "loose" cable on the leeward sides.

2nd day we had good wind and got to 20 degrees no problem. The mast was still straight, but the loweres were floppy slack again, so I hand tightened them again.

So I've done what most articles I read said to do (as well as the rigger who helped me step the mast). I put the Loos tension gauge on back at the dock and here's my question after the readings. My cap shrouds are at 12%, the forward loweres are at 9%, the aft lowers are at 7% and the back stay is between 9 and 12% (I have a slight rake on the mast).

Are these number high enough? I don't know what "good" looks like. I probably wouldn't be asking this question if I didn't have a gauge. :eek:

Dave
 

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IDK, that seems pretty loose to me, on my C22 we went 25 on the fore shrouds and 16 on the two aft shrouds. We have pretty light winds at my inland lake in Arizona.

I know every boat is different but your numbers seem low.. Check out link.

Catalina-22
 

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Go to http://www.riggingandsails.com/pdf/selden-tuning.pdf and look for the 'meter stick method' of setting/verifying correct rig tension - without a tension gage. Proper rig tension is important for how your jib/genoa sets and takes its proper shape; and, is quite important with regard to 'pointing ability'. Your 'lowers' numbers seem too loose. Most boats need ~12% backstay tension for sailing in or less than 12Kts apparent so that the forestay sag is under control.

Sometimes even 'brain surgeons' make mistakes.
 

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good stuff above

Im about to test sail tune my boat after replacing some rigging

there is a method out there that instead of tightening up the leeward lowers while sailing you actually tack over and adjust the opposite side, tack back over and see if you eliminated the sag while always sighting the mast up the mainsail track...

on my boat its recomended that dock side you only use the forward lowers for static tuning...and get correct toughtness, after first getting correct mast rake forward and aft with forestay and backstay first.

then its uppers to get mast inline...intermediates and finally lowers...

then only then after everything is kosher you tighten up aft lowers the reason being is if they are tight to begin with you wont get the correct rake and most importantly BEND in the correct posotion regarding the mast for sail shape(main).

also because the aft lowers are deck attached only and will possibly give you false readings and loosen up and therefore you will retighten only to get a reverse bend on the mast

on my boat or anyboat with dual lowers its recomended that the forwward ones be substantially tighter or lets say around 25% tighter than the aft ones...all other things considered...

also and this is just me rig tuning is absoltuely BOAT SPECIFIC...there are great tuning guides out there and general sail setting and shape guides etc...but always on boats tuning is specific to your boat, year model and at times personal from boat to boat...cause you are also dealing with hull flex, deck structers, age of rigging etc...

good luck!

ps as an aside note...I prefer slightly LOOSE than too tight...too tight will cause more damage and stresses in hardware, plates, decks attachments etc...than slightly lose...

also racers for the most part have slightly loser rigs(for the most part) dock side tune than cruisers and daysailors...

for cruising basically its mast in line when sailing and call it good
 
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this is my current boats tuning GUIDE

Mast Systems

its a no tension gauge way of doing it, I also beleive that just using numbers its easy to screw up more than going by feel and mast bend rake, side to side etc...whats paramount is to always test sail and tune the rig why sailing...
 

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Hi All,

This question is for you who have experience tweaking standing rigging. The rigging was "dock tuned" by a pro rigger. I went out and had some wind this weekend and hope I finished the tuning correctly.

1st day we only had enough wind so that no matter how tight I pulled the sails in, we could only get a max of 12-15 degrees of list. I was clearly able to see the mast top leaning to leeward along with the slack lower shrouds on the leeward side. Lightened the cap shrouds so I had a straight pole and tightened the lowers hand tight to remove the "loose" cable on the leeward sides.

2nd day we had good wind and got to 20 degrees no problem. The mast was still straight, but the loweres were floppy slack again, so I hand tightened them again.

So I've done what most articles I read said to do (as well as the rigger who helped me step the mast). I put the Loos tension gauge on back at the dock and here's my question after the readings. My cap shrouds are at 12%, the forward loweres are at 9%, the aft lowers are at 7% and the back stay is between 9 and 12% (I have a slight rake on the mast).

Are these number high enough? I don't know what "good" looks like. I probably wouldn't be asking this question if I didn't have a gauge. :eek:

Dave
dave there is also the slack check on rigging...

what is your lateral slack on all shrouds and stays...

for static tune...do your cap shrouds have 1.5-2 inches slack from center

and compare that to your lowers, they should have 2 inches to 2-5 later movement especially the aft ones

backstay at rest if adjusteable should be way loose and floppy

etc...
 

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So I've done what most articles I read said to do (as well as the rigger who helped me step the mast). I put the Loos tension gauge on back at the dock and here's my question after the readings. My cap shrouds are at 12%, the forward loweres are at 9%, the aft lowers are at 7% and the back stay is between 9 and 12% (I have a slight rake on the mast).
That is too loose.

Having the numbers that low reduces stress on the chainplates and standing rigging, but increases it on the mast.

This inexpensive book does a very good job of explaining how to tune your standing rigging, also has good instructions on adjusting running rigging to maximize your sail performance, and is small enough and easy enough to follow to leave on the boat:
Sail and Rig Tuning: Ivar Dedekam: 9781898660675: Amazon.com: [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/51Cd5vcK%[email protected]@[email protected]@51Cd5vcK%2BzL
 

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A slack rig is far more damaging than a tight one. Movement and shock loading hurts, constant (proper) tension does not. For all the money people spend on boats, a Loos gauge is really not expensive. Buy one, follow the directions, and do it correctly.
 

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Discussion Starter · #10 ·
Hi All,

Just got off the phone with the rigger that helped step the mast and dock tune. He suggests that if at 15 degrees I had the mast straight and in column and slack removed it was good. Then at 20 degrees, verified the mast still straight and in column, removed the slack and used the Loos (back at the dock) just to compair values side to side (which were spot on equal), it was time to put in the pins and call it good. Check things every now and then.

I have an older boat, that came with NO instructions for stepping the mast and rigging adjustment other than to "hire a proffessional rigger". I like the not too tight discussion. Why tighter than it needs to be? Thanks for the input ya'll.

Dave
 

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A slack rig is far more damaging than a tight one. Movement and shock loading hurts, constant (proper) tension does not. For all the money people spend on boats, a Loos gauge is really not expensive. Buy one, follow the directions, and do it correctly.
This.
Shock loading is bad.

I required 15% on a Loos Gauge to get shrouds so that they were not sloppy on the leeward side. Slightly soft is acceptable. If you achieved that with 12%, then good for you.

I'm not sure if your rigger educated you as he worked, or if he just did the job and left, but the forward lower shrouds should be tensioned to put a slight pre-bend in the mast. "Telephone pole" rigs like yours and mine will only achieve a slight amount of pre-bend.

The lower shrouds will and should be more slack than all the rest. Their primary function is to check mast "pumping" when sailing, or when the wind blows across the spar just the right way.

If you knew this already, I apologize.
 

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ps as an aside note...I prefer slightly LOOSE than too tight...too tight will cause more damage and stresses in hardware, plates, decks attachments etc...than slightly lose...

also racers for the most part have slightly loser rigs(for the most part) dock side tune than cruisers and daysailors...
Im a racer and aggressive long distance cruiser, I often to validate my 'settings' by using a rig tension gage while underway and when 'hard over' so that the caps and lowers when at the heel angle I normally 'max-out' at doesnt go much or often go beyond 30% tension - 30% is where stainless rigging begins to 'yield' or develop permanent 'stretch'. Also constant cycling the rigging beyond 30% leads to rapid premature metal fatigue in the wire and end fittings, as well as chainplates.
 

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bingo!

its natural to think that a bit tighter wont do harm but it does...

Im not saying have the mast jumping around all loose and slapping but people OVERALL have the tendency to overtighten things...

just look at guys using torque wrenches...only to strip stuff saying they didnt acheive proper torque

in a lose sense the same applies to rigging, sheeting, running rigging too
 

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Im a racer and aggressive long distance cruiser, I often to validate my 'settings' by using a rig tension gage while underway and when 'hard over' so that the caps and lowers when at the heel angle I normally 'max-out' at doesnt go much or often go beyond 30% tension - 30% is where stainless rigging begins to 'yield' or develop permanent 'stretch'. Also constant cycling the rigging beyond 30% leads to rapid premature metal fatigue in the wire and end fittings, as well as chainplates.
Are you saying to take tension measurements while sailing at the most efficient heeling angle for the wind condition and that tension should be no more than 30 per cent of breaking load?
What then do you prescribe for the lee shrouds, just snug, hanging..., or does it matter so long as they do not exceed 30 per cent of breaking load when loaded?
Also if I read this correctly, what point of sail do you recommend when taking tension readings as point of sail will greatly affect fore stay and aft stay loads?
John
 

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God, not this again.

Rigs aren't tuned by hitting some number on a loose gague. They just aren't. The ideal mast tune is set by having the mast perfectly in colume at the current wind speed and sail selection, with the proper forestay tension, and mast bend.

That's the goal. Period.


But just a FYI if you are carrying 30% of the shrouds MBL then you are way past the max design load of most standing rigging. The normal safety margin is 5:1, so the max load most shrouds are designed to is 20%. Past this you start doing fun stuff like bending the hull, causig the deck to pop off, ripping chainplates thru the deck, ect.
 

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yup those that say just go by the numbers or gauge are playing with fire and honestly not giving great advice...

but I agree on the not this again is true...its like what is the best oil?

you tune on the water and static tune at the dock or mooring etc

basically mast in line while static and sailing...thats about it...

avoid overtensioning by all means
 

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Sorry to disagree but standard / typical boat design for rigging and spars DOES approach standard / recommended 'numbers' on a tension gage for the BASIC rigging settings. Every mast supplier will give you these numbers which are typically at ~12%UTS for sailing in moderate conditions and which equates to a normal accepted safety factor (FS) of a minimum of FS≥3 for offshore boats, ≥2.0 for coastal design and ≥1.5 for inshore.
Such 'numbers' are derived typically by doing theoretical calculations or by actual measurement of the resultant rig forces on the caps, and lowers, etc. on a boat at a ~45° angle of heel, and then multiplied by the intended --SAFTEY FACTOR-- of the design type .... all to insure that the rig doesnt stretch beyond the limits of plastic deformation (yield) which is typically ~30% for 300 series stainless and approximately where the all important fatigue endurance limit for 300 SS also occurs.
So if you want to argue about 'numbers' be prepared to argue with all the spar and rigging manufacturers as these BASIC numbers are in alignment and agreement with standard accepted broadscale precision static and dynamic structural practice ... then you can tweak all you want, but ultimately you will arrive quite close to these 'numbers'.
Seldén is an example of a leading spar supplier http://www.riggingandsails.com/pdf/selden-tuning.pdf ... take a look their manual at all those recommended GAGE % NUMBERS as the basic settings, as these settings will be VERY close to the actual on-the-water tensions to accomplish the minimum resultant to-the-boat stress induced loads AND to keep the mast in column AND to keep the forestay/headstay at the proper catenary sag which the sailmaker also depends when cutting a sail.
So in conclusion all three entities - boat designer, rig/spar manufacturer, and sailmaker all design, engineer and manufacture based very closely to these 'numbers' and strengths and inherent factors safety.
There ain't NO other way to do this ... for sailboats, for aircraft, for cars/trucks, for anything that 'moves' and that carries people.

;-)
 

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it was a bit tongue and cheek...

like going by torque numbers on torque wrenches and getting mad cause you kee stripping old bolts or new bolts in old engines etc..etc...happens all the time

those that use only one method are often fooled into a sense of security only to sometimes get bit in the end

I agree with you completely on industry standards, rigging strength, wire strength mast tunings, general guidelines etc...BUT the key is your boat for your specific sailing scenario

using selden for an old mast or wooden mast or aint gonna do jack for your boat

so while the numbers are all there and industry standards what I was emphasizing is real world tuning and testing on the water

to aid those numbers

thats all I was saying really
 

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Rich,

My J-22 had tune setting that ranged between 135 and 467lbs depending on the wind. On 5/32 304 1x19 wire (3300lbs MBL). So our tuned settings ranged from 5% to 14% on the nominal MBL of the wire. Sure 12% falls inside that range, but so do a lot of other numbers. And getting enough tension on the wire is only the last step in a process of getting the mast tuned properly.
 

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A manufacturer as Seldéns may very well have rather good control on their parts, mast, wires and so on. Then it is easy to recommend 20% of max load.

But there are some other weak points:
- turnbuckles. These gall very easy when made in stainless.
- hull and chainplates (I have seen many destroyed chainplates just due to high rigg tensions).

The 20% may be for those racing, wanting to get optimal performance and pay the price for it. Cruising - is a fraction of a knot important? Lowering stress somewhat (to, say, 10%) will decrease stress on the hull considerably.

Then, one must think some:
On a MH rigg, the aft stay is used to get high tension in the forestay. Generally, the mast should be stright, it is often also dimensioned for that. To induce a bend in a heavy dimensioned mast requires a lot of tension.
From stress point of veiw the MH mast is superior. All forces ar handled.
Then .. those who starts adjusting (during sailing) aft stay what is the expected result? One things is for sure: the mast top will move back & down. This the side rigg will be more slack ....
The exclusive alternative is to use hydralics to pump up the mast. Works better, but this is expensive (and of course increase all stress).

A partial rigg is -principally- designed för being trimmed. Thinner cross section, in order to be able to bend. With the 9/10ths one never knows, these could be a MH is disguise.
Most of us use to trim the aft stay on thse partial mastas. With about the same result as with a MH: mast top is moved back & down. Side rigg tension is decreased, and mast topp is also moving to lee, spilling some wind from the top.
If this behaviour is decired, then there is no need to have very high tension in the side rigg - and certainly not in the fore & aft stays.

/J
 
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