OK, who wants to throw babystay tension into the discussion of sail shape? Joel
On Mon, Apr 19, 2021 at 12:04 PM CHARLES SCHEAFFER via CnC-List < cnc-list@cnc-list.com> wrote: > Hi all, > IIRC, Our boat has a -10 rod capable of 10,000# load. The owners manual > states not to exceed 40% of rod strength on the backstay hydraulic ram so > our setup relieves around 3500 and we stay below that. We have a remote > pump panel and the relief is adjustable. I set it myself after I had mine > rebuilt by a local Ram shop. I believe excessive pressure will initially > stretch the rod and more pressure will cause it to break. On board the > boat, we adjust backstay by looking at the sails and only use the gauge as > a safety reference. A batten is taped to the ram to indicate repeatable > settings. > > FWIW, Something I keep experimenting with: It's important to set the > headstay and backstay length properly so the backstay works the way you > want. It's part of tuning and done after the mast is centered and the > shrouds are tensioned fully. In lighter air, you may want to bend the mast > a little and flatten the mainsail before tightening the headstay > excessively. In stronger winds, you may want the headstay to tighten > before flattening the main. The PO used to add a 2" toggle to the headstay > for light winds to lengthen the headstay and remove it for winds over 15 > knots. This reduces the rake slightly and gives the backstay slightly more > leverage and quicker response in higher winds and you get the right shape > before bottoming out or exceeding thresholds. > > Chuck Scheaffer 1989 C&C 34R, Pasadena Md > > > On 04/19/2021 11:06 AM Jeffrey A. Laman via CnC-List < > cnc-list@cnc-list.com> wrote: > > > Hi All. Also wanted to comment on the pressure question. As I noted in > my post about the NavTec - 10 failure, I have been examining all the issues > that I more or less ignored or was happily ignorant of till now. One item > was to determine the yield and breaking load on my backstay and correlating > backstay shortening to load. If you do a little geometry and have > knowledge of stress/force/strain/elongation, it is a fairly simple > determination (I am a structural engineer). Others have provided photos of > simple shortening measure devices, which I now intend to make and install. > If others have photos, please share! But, one comment on pressure and > force -- the pressure on the hydraulic backstay is directly related to > force. So, if I trouble myself to read it, I will pay much more attention > to the pressure on the gauge right in front of my face. At the moment, I > don't recall what I read -- either NavTec or SailTec, or maybe both, 1000 > psi = 1000 lbs force. The NavTec - 10 has a relief valve set to 4000 lbs. > SailTec - 10 is 4750 lbs. Others with more knowledge may have more > definitive information. Long story but I received the wrong SailTec - 10 > the first time -- a custom unit for J105s that has a pressure relief at > 3000 lbs. > > Excellent discussion, btw everybody! > > Jeff L. > > > ------------------------------ > *From:* Edd Schillay via CnC-List <cnc-list@cnc-list.com> > *Sent:* Sunday, April 18, 2021 3:04 PM > *To:* Stus-List <cnc-list@cnc-list.com> > *Cc:* Edd Schillay <e...@schillay.com> > *Subject:* Stus-List Re: Hydraulic backstay adjuster pressure? > > Bruce, > > You may find this article interesting: > https://www.sailingworld.com/getting-most-from-your-backstay/ > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.sailingworld.com%2Fgetting-most-from-your-backstay%2F&data=04%7C01%7C%7Cd3bfbd243ace446e7faa08d9029cd2fa%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637543694834999454%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=smkRPe%2FC7SoZvMsQlt7WcZs5QqU7SNdPAHUnv0jHi2A%3D&reserved=0> > > > All the best, > > Edd > > > Edd M. Schillay > Captain of the Starship Enterprise > C&C 37+ | Sail No: NCC-1701-B > Venice Yacht Club | Venice Island, FL > > > > > > > > > > > > On Apr 18, 2021, at 2:05 PM, Bruce Whitmore via CnC-List < > cnc-list@cnc-list.com> wrote: > > Hello all > > With all of the discussions about hydraulic backstay adjusters, and mine > being fixed (finally), where do most of you keep and use the pressure? At > the dock vs. sailing and under what conditions? > > Thanks! > > Bruce Whitmore > 1994 C&C 37/40+ > Thanks to all of the subscribers that contributed to the list to help with > the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray > <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.paypal.me%2Fstumurray&data=04%7C01%7C%7Cd3bfbd243ace446e7faa08d9029cd2fa%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637543694834999454%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=FQbJL0AbzD%2FsK2R9lqD%2Bsmu7EGNJGm7cTKs7uo6UfRY%3D&reserved=0> > Thanks - Stu > Thanks to all of the subscribers that contributed to the list to help with > the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - > Stu > > Thanks to all of the subscribers that contributed to the list to help with > the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray Thanks > - Stu -- Joel
Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
