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Discussion Starter #41
Knothead, thanks for the good post, it enriches everyone's expereinces here to have guys like you around, thanks.

I don't have time to make one, but do you know where one can find the shroud breaking loads tables according to thickness, that shows both metric and imperial?

It would be good to add it here, if someone cares to do it. Thanks

Alex
 

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Knothead, thanks for the good post, it enriches everyone's expereinces here to have guys like you around, thanks.

I don't have time to make one, but do you know where one can find the shroud breaking loads tables according to thickness, that shows both metric and imperial?

It would be good to add it here, if someone cares to do it. Thanks

Alex
Alex, most of the catalogs that list Stainless wire used to have the breaking strengths listed for the various types. I seem to remember they sometimes listed safe working loads too. I'll look around and see if I can't find something.

Then I'll try to figure out how to scan it and then attach it. I'm not really adept at that stuff though. :rolleyes::)
 

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I tuned my rig for twenty knots I figured that was good middle ground for us.
And did not exceed 15% on the lowers 20% on the caps.
How does one go about optimizing the rig for 20Knots?

The rig I would like to set is a twin spreader aft swept 7/8 rig with a set of lowers and intermediates. The mast is a keel stepped affair. The mast is held firmly at deck level but the base can be moved fore-aft.

Currently the boat is getting quickly overpowered in high winds, constantly broaching into the wind in the gusts. It looks like pulling hard on the backstay and cummingham has little effect in flattening the middle part of the sail.

My other problem is that I do not own the boat so, of course, before playing about with other people's stuff one must be extra careful on what one is doing.

From the excellent info found in this thread I conclude that, for this rig setup,
the rake will be determined by the forestay length while the prebent will then be primarily determined my moving the mast base fore-aft keeping the shrouds fairly tight. The uppers should then be set to the 15% loading mentioned earlier.

It would seem then, that to optimise the rig for 20knots, say, one has to play about with the lowers and the intermediates.

Currently reducing the tension on the lowers results in some significant bending of the rig forward when pulling the backstay but the bent is nowhere near the 2% of mast length originally mentioned by Alex. Also the leeward shroud now becomes fairly floppy when sailing at 20knots so I am not sure if we have created another problem with the mast bending to leeward.

By the way, getting a rigger with a loos guage did not help much as apparently all he did was set the tension in the upper shrouds in port and more importantly the broaching problems remained.

regards
 

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I think we need to know what type of boat you are sailing to determine if the problems you describe can be associated with the rig or not. Some issues with broaching or helm balance are more associated with the sailplan or a particular hull design and without knowing these things I can't say whether or not it is due to improper adjustment of your rig.
 

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I think we need to know what type of boat you are sailing to determine if the problems you describe can be associated with the rig or not. Some issues with broaching or helm balance are more associated with the sailplan or a particular hull design and without knowing these things I can't say whether or not it is due to improper adjustment of your rig.
The boat is an Elan 37. The sails are Tape Drive racing sails.

Asking around on the WEB indicates that this boat does pretty well on the racing circuits even in high winds.

By the way I am not not necessarily saying that the rig is set up incorrectly. Merely that it is another paramater to check.

regards
 

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Seems to me that your boat is similar in design to the J-105; in rated area and size, etc. I can't say for sure about the sailing properties because it appears that Elans are primarily sold/sailed in Europe. The listings on Yachtworld only show them available in Europe/UK. That's why I hesitate to say exactly what the problem is.

If I were betting; I'd say that the problem is due to the high SA/D ratio and that the boat is getting overpowered earlier than a heavier boat or a boat with less sail area. The J-105 fleet racers say that they are a beast in heavy wind and they are always cranking the backstay up and spilling the traveler down to keep the boat on it's feet; of course they are pushing it to the limits when racing in their fleet. These tactics also require a crew who is constantly trimming and "rail meat" to help stabilize the boat.

Again; I'd try reefing it down good and then see how the boat performs. You'd be amazed that when you reduce sail area; your leeway reduces, the boat stands up and is able to sail at a more optimal angle of heel and can actually go faster. Your pointing might be a bit reduced depending on sail shape but hey if the boat goes faster and is easier to control you are going to make your destination more quickly and with less struggle.
 

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Discussion Starter #48 (Edited)
Xuraax,

I remeber writting something to you about your boat not long ago SEE HERE (I even was criticized a few posts after, when I know the boat, and know what it can do, from being on them, not from reading in magazines or bla bla bla)...

I had told you once that somethings are just the way they are, and must be changed to act differentely.

What happens is your boat may be dressed like a race boat, smell like a race boat, be among racer boats, even looks like one, and sometimes go fast as one, BUT it is not a race boat.

It's a fast normal production boat that can be sailed faster than normal and faster than the others..(but it's limited to a wind envelope)...

It still behaves like a cruiser, even if you add rake, tension, etc. It's a cruiser...designed as a cruiser, has a cruiser keel, and rudder, and hull shape...

You need to modify the keel, modify the rudder, lighten the boat, and make the boat go thru a racing oriented modification for it to handle the winds in Malta..specially when you start getting above 18kts.

There is little you can do without modifying it... you need to have a fast main traveller system, longer and thiner keel, a longer rudder, a different mast, different genoa controls, etc..

Some things are just like they are...your boat was made to sail faster than the other same type boats, but it has many many limitations...

A Ford Focus will never be a Porsche, even if you put stickers and go fast stripes on the doors..

Now, change the suspensions, brakes, engine etc...It will do as a Porsche, go fast as one..BUT it will never be one...

You need to start investing heavily (I know believe me) to make the boat do what you want..THAT boat will not behave good in strong winds, its a low to moderate wind boat...that boat is just a regular fast cruiser, like a Dehler or a Grans Surprise, it will never be a Sinergia or a B&C...

And to be honest...investing in that boat to bring it to do what you want..might as well buy an old IMS off the Copa del Rey in Spain, and then you'll be driving the Porsche...
Sorry
 

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Gui-

It isn't even Xuraax's boat... :)

.....

My other problem is that I do not own the boat so, of course, before playing about with other people's stuff one must be extra careful on what one is doing.

...
 

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Thanks one and all for the many replies.

However this thread is not about whether this boat is a good racer or not. That may well be the final conclusion when all things are checked and confirmed to be correctly set.

The thread is about adjusting the rig, and recently it had shifted into how to optimise the rig for higher winds. That is surely an interesting argument.

regards
 

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Great post, Giu!

Precisely I have a problem with the rigging and I was looking for an expert to help me fix it.

Only one suggestion, I am not acquainted with the cable measurements (1/4, 3/16, 5,16). Do you have at reach the equivalence in mm for you neighbours? (Well, I am not exactly your neighbour because I'm Catalan so we have Spain in between.... :D )

Thanks a lot!
 

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Discussion Starter #52
Great post, Giu!

Precisely I have a problem with the rigging and I was looking for an expert to help me fix it.

Only one suggestion, I am not acquainted with the cable measurements (1/4, 3/16, 5,16). Do you have at reach the equivalence in mm for you neighbours? (Well, I am not exactly your neighbour because I'm Catalan so we have Spain in between.... :D )

Thanks a lot!
Actually the tables I have are in millimiters. But for the guys here at sailnet I had to covert from KN and Kg to Inches and Pounds.

Here is a tble I made in Excel and took a snap shot, that should make it clear for everyone in Inches and Millimiters, KN, Kg and Lbs.

 

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Nicely done. :)
 

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Actually the tables I have are in millimiters. But for the guys here at sailnet I had to covert from KN and Kg to Inches and Pounds.

Here is a tble I made in Excel and took a snap shot, that should make it clear for everyone in Inches and Millimiters, KN, Kg and Lbs.

Yuppi!
Double thanks!
I'll be working on it this weekend.
 

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In order to check the lateral position of the mast use the main (or jib for fractional rig) halyard and swing it to the port and starboard rails.

Don't forget to sight up the mast to look for bends. The lower shrouds can be used to straighten some of the bends. Often times the lowers are set looser to allow for mast bend. In fact in some racing classes the lowers are adjusted according to the wind speed.
 

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Newby questions. How do you tension the shrouds on a three stay rig where the mast comes down after each use? How do you bend the mast with a three stay rig and no aft stay? The thin metal strip shrouds have to be disconnected to adust them. You place the mast thru the deck, connect the shrouds, connect the fore stay, pin the foot, and then you final tension the shrouds using the fore stay turnbuckle on my boat. There are upper turnbuckles on the upper ends of the flat metal strip shrouds. I could make balancing adjustments to balance the tension side to side with a ladder and the oak tree in the yard the way it is set up. Should the turn buckles be at the deck and the end that has to be taken loose to adjust be attached to the strap on the mast? Do you reverse them to get the adjustment made and then put them back as they were?
How much fore stay tension do you use when you have a mast that uses the deck as a pivot point?
How much rake is correct on a comet class boat with a shorter mast? It came adjusted for a foreward rake.
Does sail type change the answers? I have old canvas sails.

Sorry for all the questions, but I am trying to learn as much as I can before I do something really dumb from not knowing the correct procedures.
 

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Giu,
There is something wrong with your statement that 1mm of stretch = 5% of breaking load. This has to be 1mm of stretch per 1 meter of length, or some other ratio. I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!
 

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Discussion Starter #58
Giu,
There is something wrong with your statement that 1mm of stretch = 5% of breaking load. This has to be 1mm of stretch per 1 meter of length, or some other ratio. I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!
Maybe it was the way I wrote it.



c) Now for the main shrouds, if you don’t have a Loos, or are just a cheap person, you can use a measuring tape. I did for many years.

You will need to attach a tape of at least 2 meters to the shroud, so that the zero or the beginning of the tape starts at the turnbuckle.

The rule is simple each 1mm of stretch means 5% of the breaking load, and that is valid for ANY CABLE IN A SHROUD, no matter what the diameter is!!!
 

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I used to build a system that used a 1/4" cable 800 feet long. Proper tension on that system was to stretch the cable 8 FEET!
Yes; that was why I did the calculation on page 3 to show what theoretical length would be needed to stretch a cable to 15% break strength. It's dependent on the pre-tensioned length of the wire (and type of metal); not diameter.

15% break strength on an 800' (type 316) cable would be to stretch it approx. 6 feet. (Not accounting for thermal expansion or weight); so depending on the type of wire you were probably at about 20% break strength or a bit higher.

Giu's rule-of-thumb will put approximately 20% breaking strength into the shroud if you stretch 1mm per meter of cable. So a mark at 1 meter should move up 1mm on a scale attached to the shroud swage. For 10% breaking strength stretch 1mm per 2 meter length measurement.
 

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Discussion Starter #60
Keel, I am not going to argue this anymore.

You surely have heard about Selden masts, right?

Please allow me to redirect you to their shroud adusting manual.

PAge 30

PAge 31

PAge 39

I am sure your calculations are all correct and such..I got this this morning off the net by googling tension shrouds, and found this manual.

There are several more with the same instructions.
 
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