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1109Re: [j4x-owners-group] Generic tuning question - pre-bend.

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  • Bernard Coyne
    Nov 11, 2013
    • 0 Attachment

      Hi Tom and Barry:

      That tuning guide is for the carbon spar which all J/120's had as standard equipment.  They worked well for us with J/42 hull #3 with a carbon spar.  When you use the forestay length and shroud tensions in the document, you should get about 1" of prebend.  Rake is a different matter.  All the J/42's I have seen have plenty of rake...in fact most J model boats seem to have a lot of rake relative to most other sloops.  

      Bernie




      Bernie Coyne
      Sr. Technical Marketing Manager
      DevOps Collaborative Development Practice
      IBM Software Group, Rational
      Phone:  720-396-6297
      Email:   coyneb@...

      DevOps for Dummies - Your free guide to faster, continuous software delivery





      From:        Thomas Keffer <tkeffer@...>
      To:        j4x-owners-group@yahoogroups.com
      Date:        11/11/2013 09:39 AM
      Subject:        Re: [j4x-owners-group] Generic tuning question - pre-bend.
      Sent by:        j4x-owners-group@yahoogroups.com




       

      Bernie,


      That North guide gives the prebend at "less than 1 inch," which sounds very small. Is this for the aluminum mast?

      The J/120s also commonly use checkstays.

      -tk


      Tom Keffer
      keffer@...
      +1 541-386-8891 (h)
      +1 541-490-9507 (c)

      Skype: tkeffer


      On Mon, Nov 11, 2013 at 6:21 AM, Bernard Coyne <coyneb@...> wrote:
       
      [Attachment(s) from Bernard Coyne included below]

      The J/42 rig is identical to the J/120 so I used this North tuning guide...



      Bernie


      Bernie Coyne
      Sr. Technical Marketing Manager
      DevOps Collaborative Development Practice
      IBM Software Group, Rational
      Phone:  
      720-396-6297
      Email:  
      coyneb@...

      DevOps for Dummies - Your free guide to faster, continuous software delivery






      From:        
      <bdwyer@...>
      To:        
      <j4x-owners-group@yahoogroups.com>
      Date:        
      11/11/2013 08:58 AM
      Subject:        
      [j4x-owners-group] Generic tuning question - pre-bend.
      Sent by:        
      j4x-owners-group@yahoogroups.com




       

      We have had our J/42 for about 5 weeks now and love her. Thankfully the PO had an espar heater installed when he bought the boat so we have used the boat every weekend here on the Chesapeake with our final weekend next week.

      Because the boat is coming out of the water soon this question may be better asked in the spring but It is very much on my mind so; how much pre-bend do you have in your rigs?

      There is a significant amount in ours (maybe 5") and in order to get the forestay tight (like when it was blowing 25 this weekend) I need to really pump up the backstay inducing what seems like too much bend.

      I have about 1.5" of thread showing below the furler so I think I can take some of the pre-bend out but I am almost thinking the forestay might be to long.

      Thanks,

      Barry
      #53


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