main chainplates torsion

[JF AIR]

Hello compac 23 experts!!!
I am right now fixing a few issues on my CP23 # 3 and I notice that my port and stbd main chainplates have been torsionning to an aprox 20-30 degrees fwd...My understanding is that my mast tuning was inadecuate...I also like to keep a fair tension on my headstay ( FF2 furling sys...)
Has anybody some interesting comments over that  issue...
Would I flattened back to normal the plates or are they now to weakened???
How is it to replace those?
JF frm Montreal

[Bob23]

JF:
   I'm not sure I understand your problem. If you are saying your chainplates are bent forward 20 to 30 degrees, then, yes, I would definitely replace them. And no, I would not recommend you tune your own mast.
   Do you have any photos of this?
Bob23 in NJ

[Salty19]

Hi JF,

Been following your restoration.  Boy you have your hands full!

I don't own a 23 so I don't know IF they are supposed to be bent in a given direction or not.  But if they have been coerced into bending, yes I would replace them they are weak now.  Hutchins can fix you up.  I would question why they bent, likely rigging too tight or it was stressed by mast moving forward?

Good luck-can't wait to see the finished boat!

[ciswindell]

I replaced all of my chain plates this year and it is fairly simple.  Make sure you replace the bolts at the same time.  I would also say that you have your rig set up wrong if they are bending that much.  Just a guess....could your backstay be too loose and your headstay too tight causing the mast to flop forward?  Is your mast raked forward a lot? From what I read on this forum the rake on a CP 23 should be just slightly forward.  This is opposite of any other boat that I have owned.  It is usually raked a little aft.  Somewhere on the forum someone posted a method for rig tuning that should help a bit.

Chris

[skip1930]

Too much tension on the standing rigging a 'wants' to shove the mast clean through the bottom of the boat.

And as long as the chain plates have conformed to the job they need to do as stress is placed on them with the turnbuckles, who cares?
Once set after the first time the rig is assembled I figured that is the way the chain plates are going to remain.

The ultimate strength of steel [chain plates] is 10,000 lb x the thickness divided by four as a safe working load. And technically, thou I wouldn't try it,  the entire boat can be lifted from the top-o-mast. The rigging will support the boat.

skip.

[JF AIR]

I have made photos but where do I start for attaching them?

[Salty19]

Skip--- I strongly disagree.  Fatigued chainplates are NOT OK. 

[skip1930]

JF AIR didn't say that the chain plates continually flex back and forth, Did he ? Or did I miss that. If I saw a crack I'd replace the chain plate too.
Once the chain plates bend once into position, there done moving. Unless one keeps playing with them I can't fathom how they can fatigue.

skip.

I posted this about posting pics...I gave some tips on posting pics to another sailor, and here they are once more.

" I tried to post pictures, but was unable.  I'd like to know how if someone can tell me how.

David "

1~Join up with Photobucket, free. Then Scan and download to Photobucket [many other such site available as well]
2~Under each picture are a list of codes...
3~For Com Pac Yacht Owners Association site click on 'DIRECT CODE'. You see the word 'copied' appear and then fade out.
As a back up I always go up to edit and click on 'Copy' as well.

4~Then back in the 'post reply' box anywhere where your typing the text of the message, look above at the header and find this line...B  I  U  S  ect...
Look at the next line down. You see a red pinwheel thingy to the left and next to the right a -->  'yellow beach, black line of trees and blue sky'  <-- icon. Click on that.
Where ever the cursor is when that is clicked you'll see {IMG}  {IMG} ...paste the direct code between the two IMG's. Aim carefully, that is where you'll put the cursor and RIGHT click and then click again on the word 'PASTE" to put the direct code between the cursor. If spot on the code will appear between the IMG's.

Hit post and the picture will show up. If not then you were not between the IMG's or the Direct Code did not copy-paste. You can always click modify the message and try again.

skip.

[JF AIR]

[/img]

Hopefully , if this picture goes tru,you will have a better idea of the chainplate torsion
This on is the stbd...Portside has bent but not as much
JF AIR

[millsy]

JF,

Your photo didn't come through. 

While raising the mast, the lower end of the TB's can jamb and snag on the chainplates and cause them to bend/twist above hull to deck joint.  This has happened to me a few times, and as the twist was not extreme,  I just straightened them out with a couple of crescent wrenches.  Look closely at the chainplates for cracking or signs of fatigue where they are bent.  You should always have somebody checking for this when raising the mast- in my case I use a gin pole so I can cleat the purchase off and free a snag by myself.

At least on my 23, the rigging is aligned with the chainplate bolts.

Regards,
Chris
C-23 Dolce

[brackish]

Think Chris has the right idea.  I can't imagine enough forward rake to induce a 20-30 degree twist, the upper angle just isn't going to change that much.  More likely it was caused by a mast raising adventure that went wrong, i.e. no baby stay tension, and the mast swinging laterally.  Another possibility is someone trying to tune the rig, getting on the turnbuckle hard with the toggle locked up so that the everything turned rather than just the turnbuckle.  A third possibility is that someone used the chainplate as a guy anchor to the mast when it was down and being trailered

As far as your FF2 furler, your headstay is still inside that foil and that is what maintains the forestay tension.  You should never have to readjust it, tension with the backstay for proper tuning.  Bob23 indicates that he can get the tension relieved by slacking the bobstay when dropping the mast, it doesn't work on mine, I have to loosen the backstay to get the drum pin out.

Stainless steel has the ability to maintain its tensile strength after it has yielded, but since you don't know how many cycles, I would probably replace for piece of mind.

[JF AIR]

Hope the picture goes this time....
JF AIR

[JF AIR]

[Tim Gardner]

JF
click on the topic below to post pictures:

http://cpyoa.geekworkshosting.com/forum/index.php?topic=3763.0

TG