[christian.hess]

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

 

[christian.hess]

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....

 

[Stumble]

You don't tune the leeward side at all. Period. Don't. Even if they are slapping around like wet noodles you don't tighten the leeward shrouds. If it gets really bad a piece of bungee cord to keep them from hitting things is fine. But if the shrouds are this lightly loaded cycle loading is not an issue.

The correlary however is that if your leeward shrouds are this loose it likely means that the windward side shrouds are too loose and need to be snugged up.

 

[christian.hess]

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

 

[christian.hess]

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

 

[Cope44]

I hope this is not considered a thread jack but here goes..

I understand that all rigs are different as are all boats so..
I just finished rebedding my chain plates and refreshing the turnbuckels and toggels so a new tune is in oreder. My trailer sailor (Catalina 22 cant get my sig to change?) rigging 1/8th" has a breaking streangth of 2100 LBS from witch I came up with these numbers using my loose gauge and some math.

Forestay.
2100 X .15 = 315. (.15 =15% breaking streangth)
315 = @31 0n the loose gauge.

Shrouds.
2100 X .12 = 252
252 [email protected] on loose gauge.

aftstay.
2100 X .11 = 231
231 = @27 on loose gauge.

Dose this sound about right for a dry tune?

How dose one know how much backstay pressure to run?

I also do not understand the reasoning behind having the leward standing rigging slack?
How dose slack rigging not "slam over" while tacking or gybing and contribute to huge shock loads?

I hope this is not out of line and as always thanks for the time and advice.

 

[Stumble]

Cope,

I have never sailed a Catalina 22, so I have no direct information to impart. But to answer a few questions...

1) this is the North sails tuning guide for your boat. http://www.onedesign.com/Portals/106/docs/Tuning Guides/north-catalina22-tuningguide.pdf it is a really good place to start.

2)The reasons it doesn't matter if the leeward shrouds are loose is that they really aren't. Starting with the mast in column at the dock, and the shrouds snug. When you put up the sails the shrouds don't change leingth, but the leeward shrouds start to loosen. This is because the mast has fallen off to leeward and is no longer where it should be. The problem isn't that the leeward shrouds are to long, but that the windward shrouds are. So you need to tighten the windward shrouds until the mast is back in column.

The easiest way to do this is to tack the boat and tighten up the now leeward shrouds a bit then tack back over and see what happened. This gets a little confusing, and is why many people seem to think you tighten the leeward shrouds. Technically you do (since they are the leeward shrouds during the brief moments you are adjusting them), but you decide how much to tighten them while they are the windward ones.

3) the reason it doesn't matter how loose the leeward shrouds are is that... Well they really don't do anything. It is quite possible to take the leeward shrouds off the boat (not a good idea however). And for some extreme boats it has actually been contemplated while doing things like the transpac where you are on starboard tack for weeks at a time to reduce windage.

It is never a good idea to have things just bouncing around, but in reality if the shrouds are properly tightened for the conditions the leeward shrouds shouldn't be much looser than they were at the dock since the mast is in the same place. Excluding times in very light air where you don't need any pressure on some shrouds (J-22 in <3kn of breeze for instance).

4) the rig won't slam over, what happens is as the mast moves back to centerline the shrouds equalize pressure and transfer the load. If the mast doesn't move relative to the boat then there is no slamming. If it does then the windward shrouds were too loose, not the leeward ones.

 

[Cope44]

Thanks Stumble.
That is a well writen answer.
So get the mast in coloum at the dock (on trailer in my case) then tack while watching leward shrouds, Tack back over and tighten leward shrouds then tack back and recheck?

My mast has a ton of prebend in it, 8-10" I assume, This may well be from me setting the rigging to numbers. Im thinking in the future i should set the forestay first then shrouds then rearstay?

Cant access that link for some reason?

I will say I was verry surprised at just how flexable my mast realy is with functioning turn buckels and not having the rigging stuck fast in the spreaders.
Thanks again for the advice.

 

[RichH]

My mast has a ton of prebend in it, 8-10" I assume, This may well be from me setting the rigging to numbers. Im thinking in the future i should set the forestay first then shrouds then rearstay?

Any typical mast, not originally intended for radical 'mast bending', should have only a ~3/4" pre-bend for a single spreader rig. If a multi-spreader rig, should only have 1/2" pre-bend for each spreader set.

Are you talking pre-bend here to increase mast stiffness? .... or are you mast bending to radically reduce mainsail draft/flatten?

 

[Stumble]

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.

 

[Stumble]

Any typical mast, not originally intended for radical 'mast bending', should have only a ~3/4" pre-bend for a single spreader rig. If a multi-spreader rig, should only have 1/2" pre-bend for each spreader set.

Are you talking pre-bend here to increase mast stiffness? .... or are you mast bending to radically reduce mainsail draft/flatten?

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.

 

[RichH]

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.

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.

 

[christian.hess]

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!

 

[christian.hess]

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

 

[christian.hess]

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...

 

[Stumble]

Christian, that was a direct quote from the North Sails Catalina 22 tuning guide. Which means it was probably written by Chris Snow who if I remember correctly is a multi time Catalina 22 world champion. While you may dispute my process, I doubt there are many people in the world better qualified to discuss the proper way to tune a Catalina 22 than the North Sails OD experts.


Christian,

I think you and I are pretty much in agreement. I am not sure exactly where the conflict is to be honest. If you think I am lumping you in with those who tune rigs incorrectly then I appologize. I don't think that is the case.

 

[christian.hess]

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

 

[ccriders]

HELP!
I've been reading this thread as I have recently removed and serviced my chain plates and would like to insure my rig is properly tuned. On the Pearson 28 it may not be such a big deal with fore stay, back stay upper shrouds and single lower shrouds. The keel stepped mast is rather robust, more like a battering ram Hagar the Horrible would want. The stays are 1/4 inch, the uppers 7/32 and the lowers 9/32. I had no problems getting the mast "in column" at the dock, and over a couple of sails adjusted the shrouds so that there is only a little slack in the lees with a pretty good wind, and no reef in the main.
So my question is "how do you know that the mast is still "in column" while sailing?"
I have tried to lay on deck with my head at the base of the mast and sight up the mast, but I wear trifocals, and it is very hard to see a straight line for that distance, especially while heeled and crashing through the chop that normally goes with a brisk wind.
Any tricks to the trade?
John

 

[christian.hess]

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

jejeje

 

[Stumble]

John,

How precise do you want to be?

I generally just do it by eye, but there are better ways, it just takes a bit of equipment.

For the big boat I used to work on we used a jib with a laser line. We set the jig on the boat in the centerline of the boat, and could shoot a sight line up the mast right down the center of the rig. This allowed micro adjustments even on a 115' tall mast to get it as precise as possible.

More simply you can just use a spare halyard to measure the distance from the top of the mast to known points on the boat. If you are doing this you need to create an offset if the halyard doesn't exit the mast from the dead center of the boat. Most spinnaker halyards for instance are slightly favored to either port or starboard and this needs to be taken into account.