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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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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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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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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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excessive fore and aft stay tension is often the most classic abuse of tension on stays...

smile cracks and keel cracks for and aft the keel hull joint are classic examples of overdoing it

on some boats its due to the stresses racing does, on some its simpy from riggers and owners not knowing what they are doing

c and c 35 and others
islander 36

are just a couple of boats that can be severely damaged from badly tuned rigs or abuse...

be careful is all Im saying! jajaja
 

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some body asked whats good tension for LEEWARD turnbuckles or shroud sag when heeled over in say 15knots

a good comfortable "in between" tension is to have the turnbuckle not slap around so it doesnt cycle stress and crack but just tight enough to where it cant swing around...and vibrate...the wire itself should be loose and moved around easily but not enough to where the turnbuckle and toggles can acheieve significant angles and be able to slap

thats the easiest way in rough weather to have rigging failure

cyclical loading...

one could easily snap a loose shroud beating to weather in a race or 20, 30 mile tack....
 

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read the posts I mentioned before...where you tack over and tune the opposote side to eliminate the slack

dont like to quote myself but here is what I said on the first page

(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...)


I agree with you however people take this to an extreme and decide to tighten everything up equally and dont know they are stressing the rig too much
 

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btw even if not loaded just slapping around will and can cause a turnbuckle to snap...your bungee is a good idea however its better to get it right from the get go
 

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This is nonsense. Every boat has its own prefered amount of prebend, and it has nothing to do with the number of shrouds. You might be able to argue that it has something to do with mast leingth, but even that isn't really the case.

I couldn't find a different link for the North Tuning Guide for the Catalina 22, but this is from that...

The mast rake is probably the single most important element of tuning your boat. Note the mast rake should vary from fixed to swing keels with swing keels having slightly less rake.

Start with boat sitting on its lines in the water. Hang a weight from the end of the main halyard and cleat off halyard with weight and shackle 12" below the boom. Measure distance from the aft face of the mast to where the halyard crosses the boom. This measurement should be 8" for fixed keels, 6-7" for swing keels. Adjust the headstay turnbuckle to achieve desired measurement.

Tighten backstay until snug, no slack. Remove weight from halyard, attach a tape measure to halyard and haul to top of mast. Measure from side to side tightening or loosening upper shrouds until mast is centered.

Now start tightening upper shrouds until they have show 28 on the gauge. Tighten forward lowers until they show 24 on the gauge. Tighten aft lowers until they are 24 on the gauge too. To measure shroud tension use a Loos Model A Tension Gauge. The end result here is to have the mast straight fore and aft with a small amount of rake to give the boat some "bite" upwind.
now this is nonsense! the part in bold...the rest on the wieghts and side to side is very similar to what my islander 36 tuning guidelines say...by schumacher

you shouldnt be so quick to dismiss all other ways of tuning

for my boat its absolute nonsense to tighten lowers to same tension and would be the best way to get a false reading and reverse bend on the mast, also a great way to rip the lowers out of the dec or severely bulge the deck in that area...

I know many many boats that also recomend to only use forward lowers to tune mast and only after all others have been correctly tensioned do you put aft lowers in check, always looser than the forwards...also on some masts you do this so you get the correct bend by tightening the forward lowers first...tuning all others, getting bend...then correctly bending and tightening aft...with lowers...sometimes you also give the forwards another half turn or so to push the mast forward a bit.

also on boats with dual lowers most of them use the aft lowers to keep the mast from pumping excessively and also with adjusteable backstays they offer support...when downwind.

its futile to offer general tuning guides and equally futile to dismiss all others as nonsense when the most important factor in tuning your mast is your BOAT and where you sail it

for example Id much rather have someone who is an expert on MY boat give me tuning advice for various conditions...than somebody saying read this book or go talk to the rigger and thats all you need to know

thats nonsense!
 

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Prebend and mast rake are entirely different things.

Prebend is a structural means to induce mast STIFFNESS and resistance to induced harmonic vibrations (by changing the 'natural frequency' of the mast. Prebending increases "I" to the 'third power" - a function of stiffness.
All sailmakers cut the mainsail to the expected amount of normal prebend.

Rake is the vertical angle of the mast w/r to fore and aft to the horizontal plane and is set the CLR/CE AND dynamic (underway) balance of the helm.
EXACTLY

my h28 had no bend in the masts, however they were raked at least 15-20 degrees aft...

also and this has not been mentioned all tuning guides for glass boats are utterly useless for wooden boats...

it all depends on the boats and mast...

I never used any gauge on my h28...loosey goosey, older glass boats a little tighter...racing dinghies or whatever something else...

you just cant put most masts or rigs in a general tuning guide...use them as guides...but experience in each design is much more important:)
 

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For the sake of simplicity let's talk about port and starboard instead of using windward and leeward for a moment. And keep in mind that it is always better to have looser shrouds than tighter (or generally so) for a lot of reasons including sail shape, equipment durability, pressure on the boat, ect.

The order of tuning a mast is to
1) get the mast step in the right place. Fore and aft then side to side (actually the order doesn't matter I just like doing it this way.
2) get the mast centered side to side in the partners. And properly set for and aft
3) set the forestay length
4) get the mast in column with correct prebend.
5) go sailing in 8-10kn of breeze.
6) this is the tricky bit...

6a) While on starboard (wind coming from the starboard side) tack take a look up the mast and see how much the mast is falling off to port and guess how much the starboard shrouds need adjusting.
6b) Tack
6c) Adjust the starboard side shrouds
6d) tack
6e) repeat 6a-6d

Congratulations you now have gotten the gross tune for the starboard side set correctly.

7) Back at the dock (or just take down the sails in calm water) use a loose gague to measure what the starboard side shrouds are set at. Then duplicate the settings on the port side. Now reset the starboard side to the old settings (when you reset the port shrouds the starboard will tighten up a bit). And keep working the shrouds back and forth until you get both sides set at the original starboard side numbers.

8) These are gross numbers, and have you in the right ball park, but you have to redo steps 6a-6d again. The pressure of the port shrouds change this a little (how much depends on the boat).

9) repeat step 7

You can continue doing this cycle as many times as you want, but eventually the changes become pretty small and it isn't worth messing about anymore. I typically find two cycles thru the process enough for cruising, but for race boats you can get as finicky as you want.

Keep in mind that these are only the proper settings for this wind speed, higher breeze adds more side load to the mast so more tension is required, while lighter wind allows looser settings.

For a cruiser it is perfectly fine to get set up for your normal wind conditions and leave it at that, racers get pretty precise about it, with different tuning numbers for every wind speed and wave conditions. This can make a substantial difference in upwind performance even on a small boat, but it isn't structurally necessary so long as you don't use light wind tuning numbers when it is howling.

Oh it's always worth tacking over to port at the end just to double check everything, but if you have done everything properly it actually isn't necessary.
very very similar to the guide I posted a few pages back

with the only difference on lowers tuning...which is a very important distinction.

Mast Systems

all boats are different and must be treated as so...:)
 

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same here...its just semantics here and there...in my tuning guide or the one Im using for my current boat your process and mine are almost exactly the same

with the exception of the lowers

Im fully aware that som boats use equal tension on lowers, the only thing I can stress now is that each boat is different and mast, so tweak accordingly

seems we are expressing the same sentiments

rich´s info is very valuable too...lots of knowleadge on here

for example I came on here to check up on ways to take away the harmonic resonance(buzzing) I was getting after soft tuning my boat...

and Im not going to worry about it until I test sail...I know now that the best way is to tighten up my aft lowers only though after test sailing to make sure my prebend is ok...

I still have to finish tuning my rig which might be hard since I dont have so much space in this estuary but Ill get it close at least for general cruising sailing...

cheers

take care
 

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got a friend with a bit better sight? maybe a young kid that would do it for the ride? or a beer

jejeje
 
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