[Alberg30] tunning, shroud tension

[Dave Terrell]

Thanks for the info. When I looked at my Loos I came to the same conclusion. If a person went for the 10% figure the 1/4 inch stays/shourds would be set at about 850 pounds, the 3/6 shourds at about 500 pounds, and the forestay/backstay as you indicate. 

What I do not understand is why there seems to be a tendency(based on the figures provided)  to under tension the Alberg 30 rig (by Loos standards). What really puzzles me is the tendency to have little to no tension on the aft lower shroud. 

Right now I would have to assume that tensioning practice is based upon experience, but I really would like to know why it works if that really is the case. Any insight on this would be appreciated.

>>> timmins at optonline.net 01/09/02 11:38PM >>>
Sorry about taking so long to respond. It took a while to locate the info.
>From my Loos Instructions, 1/4" wire breaking strength is 8200 lbs and 3/16" is 4700 lbs. Additionally, Loos recommends 1/4" forestay set to 1300 lbs, 1/4" shrouds set to 850 lbs, and 3/16 shrouds set to 500 lbs.
The relationship of forestay / backstay is something I can't comment on directly since I've got roller furling on the forestay and therefore can't easily measure the tension there. Loos makes the statement, "Since the backstay makes a greater angle to the mast, the backstay tension will be lower than the forestay tension."
  ----- Original Message ----- 
  From: Dave Terrell 
  To: public-list at alberg30.org 
  Sent: Thursday, January 03, 2002 2:51 PM
  Subject: Re: [Alberg30] tunning, shroud tension


  How do these numbers fit with the general guidelne that shrouds should be tensioned between 10 and 12% of the breaking strength the wire? This is what the instructions for my Loos tension guide said and that has been my guideline in the past. That worked on my old boat, a CAL 27 T-2. If the application of the rule to my "new" Alberg 30 is different, I would like to know. I appreciate having this source of informatioin avaliable.

  >>> timmins at optonline.net 12/28/01 06:37PM >>>
  These are the conclusions I drew from the list when it was published in May

  Average tensions of the whole list:
  Forestay/Backstay............733
         Backstay only...................726
         Forestay only....................735.6
  Uppers.............................685
  Fwd Lowers.....................495
  Aft Lowers........................0   (loose)

  Race Boats Only Averages:
  Forestay only....................811
  No backstay only
  Uppers..............................862
  Fwd Lowers......................679

  Based on these numbers and info taken from Brion Toss's video on rig tuning
  (and his web site), This is how I set up my mast.
  Starting with the mast vertical, tighten the forestay to snug/tight  but not
  to pull the mast forward of vertical.
  Tighten the backstay to 625
  Tighten uppers to 750
  Tighten Fwd lowers to 620
  Tighten Aft lowers to slack/100

  After sailing a bit, I reset the backstay to 700
  These numbers worked very well for me and the boat was nicely balanced.

  Don't ask me to explain my logic anymore (this was done in June). I just
  happened to come across my note sheet from doing the job.
  All tensions were done with a Loos Model B, part # 90 gauge

  Regards,
  Brian
  #497
  ----- Original Message -----
  From: "George Dinwiddie" <gdinwiddie at min.net>
  To: <public-list at alberg30.org>
  Sent: Thursday, December 27, 2001 11:41 AM
  Subject: Re: [Alberg30] tunning, shroud tension
  snip
  > If anyone can draw some general conclusions from this list,
  > I think we'd all like to hear it.
  >
  snip

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