Re: Stus-List 37+ Backstay tension
Lew Townshend identified my rams a #6...whatever that means. On Fri, Aug 3, 2018, 7:36 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Were you able to get the hydraulic ram displacement vs. back stay > load? That would help those of us who don't have a working pressure gauge. > > Gary > S/V Kaylarah > > ~~~_/)~~ > > > On Fri, Aug 3, 2018 at 5:28 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Here's the data guys. It looks like there is a loose corollary (in my >> case) between hydraulic psi and backstay lbs load. My hydraulic pump >> relief valve is seized and appently set at ~2600 psi. So I'm safe in that >> no matter how much I pump it will never exceed even 25% of the backstay >> load limit. As for the transom load limit...who knows. >> >> >> https://docs.google.com/spreadsheets/d/1B6F6OQU8b7L5tVgvvWKViQHS5UVL1Srx6HV7xPKRC40/edit?usp=sharing >> >> Josh Muckley >> S/V Sea Hawk >> 1989 C 37+ >> Solomons, MD >> >> >> >> On Fri, Aug 3, 2018 at 1:48 PM, Bruce Whitmore via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> I'd love to see that as well Josh. >>> >>> Thanks! >>> >>> Bruce Whitmore >>> >>> (847) 404-5092 (mobile) >>> bwhitm...@sbcglobal.net >>> >>> >>> -- >>> *From:* Josh Muckley via CnC-List >>> *To:* C List >>> *Cc:* Josh Muckley >>> *Sent:* Friday, August 3, 2018 10:22 AM >>> *Subject:* Re: Stus-List 37+ Backstay tension >>> >>> With that info I'll head down to my boat and apply various psi to the >>> hydraulics and then measure the tension with my loos gauge. >>> >>> Josh >>> >>> On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> >>> So... I went over to Kaylarah this morning and found the following: >>> >>> The back stay diagonals are 235" long >>> The spread between the attachments is 80" >>> Doing the math, that means if the maximum tension on the vertical rod is >>> 5000 lbs., then the tension on the diagonals is 2537 lbs. >>> From here you can apply any safety factor you like, just maintain the >>> ration of 2537 : 5000. >>> Because the angle between the diagonals is so small (smaller than I >>> thought), it is pretty close to 2:1. >>> >>> Personally, I'm going to try and keep the tension on the diagonals less >>> than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I >>> put that Loos gauge?) >>> >>> Gary >>> S/V Kaylarah >>> '90 C 37+ >>> East Greenwich, RI, USA >>> >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell >>> wrote: >>> >>> Actually, if you look closely at the manual, you will notice that >>> the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". >>> Since the vertical part of the back stay assembly is rod, I will assume >>> that the 5000 lbs. refers to the vertical. I will go over to the boat >>> tomorrow and try to measure the back stay angle, to see which limit gets >>> exceeded first, the rod or the wire. C could have made this a lot >>> easier. I've got to believe the transom will fail before the wire, yet the >>> wire is all that is specified. >>> >>> Gary >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> >>> Absolutely without any doubt in my mind the backstay tension of 4125 is >>> to be measured on the mainline. This works in opposition to the head stay >>> which is equally sized #12 rod. >>> >>> Josh >>> >>> On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> >>> Hi Josh, >>> Oops! I missed that. I looked in the chapter about rigging and >>> didn't find it there. Silly me! I even searched for the number 4125 and >>> found nothing. I guess the document is an image rather than text. Now the >>> question, is that the tension in the vertical part of the back stay? I >>> guess, the safest assumption is that it is. >>> >>> Gary >>
Re: Stus-List 37+ Backstay tension
Hi Josh, Were you able to get the hydraulic ram displacement vs. back stay load? That would help those of us who don't have a working pressure gauge. Gary S/V Kaylarah ~~~_/)~~ On Fri, Aug 3, 2018 at 5:28 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > Here's the data guys. It looks like there is a loose corollary (in my > case) between hydraulic psi and backstay lbs load. My hydraulic pump > relief valve is seized and appently set at ~2600 psi. So I'm safe in that > no matter how much I pump it will never exceed even 25% of the backstay > load limit. As for the transom load limit...who knows. > > https://docs.google.com/spreadsheets/d/1B6F6OQU8b7L5tVgvvWKViQHS5UVL1 > Srx6HV7xPKRC40/edit?usp=sharing > > Josh Muckley > S/V Sea Hawk > 1989 C 37+ > Solomons, MD > > > > On Fri, Aug 3, 2018 at 1:48 PM, Bruce Whitmore via CnC-List < > cnc-list@cnc-list.com> wrote: > >> I'd love to see that as well Josh. >> >> Thanks! >> >> Bruce Whitmore >> >> (847) 404-5092 (mobile) >> bwhitm...@sbcglobal.net >> >> >> -- >> *From:* Josh Muckley via CnC-List >> *To:* C List >> *Cc:* Josh Muckley >> *Sent:* Friday, August 3, 2018 10:22 AM >> *Subject:* Re: Stus-List 37+ Backstay tension >> >> With that info I'll head down to my boat and apply various psi to the >> hydraulics and then measure the tension with my loos gauge. >> >> Josh >> >> On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> So... I went over to Kaylarah this morning and found the following: >> >> The back stay diagonals are 235" long >> The spread between the attachments is 80" >> Doing the math, that means if the maximum tension on the vertical rod is >> 5000 lbs., then the tension on the diagonals is 2537 lbs. >> From here you can apply any safety factor you like, just maintain the >> ration of 2537 : 5000. >> Because the angle between the diagonals is so small (smaller than I >> thought), it is pretty close to 2:1. >> >> Personally, I'm going to try and keep the tension on the diagonals less >> than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I >> put that Loos gauge?) >> >> Gary >> S/V Kaylarah >> '90 C 37+ >> East Greenwich, RI, USA >> >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell >> wrote: >> >> Actually, if you look closely at the manual, you will notice that >> the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". >> Since the vertical part of the back stay assembly is rod, I will assume >> that the 5000 lbs. refers to the vertical. I will go over to the boat >> tomorrow and try to measure the back stay angle, to see which limit gets >> exceeded first, the rod or the wire. C could have made this a lot >> easier. I've got to believe the transom will fail before the wire, yet the >> wire is all that is specified. >> >> Gary >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> Absolutely without any doubt in my mind the backstay tension of 4125 is >> to be measured on the mainline. This works in opposition to the head stay >> which is equally sized #12 rod. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> Hi Josh, >> Oops! I missed that. I looked in the chapter about rigging and >> didn't find it there. Silly me! I even searched for the number 4125 and >> found nothing. I guess the document is an image rather than text. Now the >> question, is that the tension in the vertical part of the back stay? I >> guess, the safest assumption is that it is. >> >> Gary >> >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> Page 68 of the manual pdf file which I linked before has the pre-load and >> max load limits. >> >> Again I am corrected in my preconceived notions regarding the correlation >> between a hydraulic gauge and the tensile load on the back stay. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>
Re: Stus-List 37+ Backstay tension
Here's the data guys. It looks like there is a loose corollary (in my case) between hydraulic psi and backstay lbs load. My hydraulic pump relief valve is seized and appently set at ~2600 psi. So I'm safe in that no matter how much I pump it will never exceed even 25% of the backstay load limit. As for the transom load limit...who knows. https://docs.google.com/spreadsheets/d/1B6F6OQU8b7L5tVgvvWKViQHS5UVL1Srx6HV7xPKRC40/edit?usp=sharing Josh Muckley S/V Sea Hawk 1989 C 37+ Solomons, MD On Fri, Aug 3, 2018 at 1:48 PM, Bruce Whitmore via CnC-List < cnc-list@cnc-list.com> wrote: > I'd love to see that as well Josh. > > Thanks! > > Bruce Whitmore > > (847) 404-5092 (mobile) > bwhitm...@sbcglobal.net > > > -- > *From:* Josh Muckley via CnC-List > *To:* C List > *Cc:* Josh Muckley > *Sent:* Friday, August 3, 2018 10:22 AM > *Subject:* Re: Stus-List 37+ Backstay tension > > With that info I'll head down to my boat and apply various psi to the > hydraulics and then measure the tension with my loos gauge. > > Josh > > On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > > So... I went over to Kaylarah this morning and found the following: > > The back stay diagonals are 235" long > The spread between the attachments is 80" > Doing the math, that means if the maximum tension on the vertical rod is > 5000 lbs., then the tension on the diagonals is 2537 lbs. > From here you can apply any safety factor you like, just maintain the > ration of 2537 : 5000. > Because the angle between the diagonals is so small (smaller than I > thought), it is pretty close to 2:1. > > Personally, I'm going to try and keep the tension on the diagonals less > than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I > put that Loos gauge?) > > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell wrote: > > Actually, if you look closely at the manual, you will notice that the > 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". > Since the vertical part of the back stay assembly is rod, I will assume > that the 5000 lbs. refers to the vertical. I will go over to the boat > tomorrow and try to measure the back stay angle, to see which limit gets > exceeded first, the rod or the wire. C could have made this a lot > easier. I've got to believe the transom will fail before the wire, yet the > wire is all that is specified. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > > Absolutely without any doubt in my mind the backstay tension of 4125 is to > be measured on the mainline. This works in opposition to the head stay > which is equally sized #12 rod. > > Josh > > On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > > Hi Josh, > Oops! I missed that. I looked in the chapter about rigging and > didn't find it there. Silly me! I even searched for the number 4125 and > found nothing. I guess the document is an image rather than text. Now the > question, is that the tension in the vertical part of the back stay? I > guess, the safest assumption is that it is. > > Gary > > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > > Page 68 of the manual pdf file which I linked before has the pre-load and > max load limits. > > Again I am corrected in my preconceived notions regarding the correlation > between a hydraulic gauge and the tensile load on the back stay. > > Josh > > On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > > Hi Josh, > Where did you find the 4125 or 5000 lb. limit? I don't see that in > the Owners Manual? Is the 4125 lb. limit for the lower angled segments of > the the back stay or the upper vertical part. You can't simply measure the > port back stay tension and multiply by two, because of the angle between > the two. You would have to measure the angle and apply some trig to get > the right value. Mike Cotton's boat was the one I was referring to in my > email above. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > > The manual says limit to 4125lbs and then says absolute max of 5000lbs. > https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNna > zViYkZzRVR
Re: Stus-List 37+ Backstay tension
I'd love to see that as well Josh. Thanks! Bruce Whitmore (847) 404-5092 (mobile) bwhitm...@sbcglobal.net From: Josh Muckley via CnC-List To: C List Cc: Josh Muckley Sent: Friday, August 3, 2018 10:22 AM Subject: Re: Stus-List 37+ Backstay tension With that info I'll head down to my boat and apply various psi to the hydraulics and then measure the tension with my loos gauge. Josh On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List wrote: So... I went over to Kaylarah this morning and found the following: The back stay diagonals are 235" longThe spread between the attachments is 80"Doing the math, that means if the maximum tension on the vertical rod is 5000 lbs., then the tension on the diagonals is 2537 lbs.From here you can apply any safety factor you like, just maintain the ration of 2537 : 5000.Because the angle between the diagonals is so small (smaller than I thought), it is pretty close to 2:1. Personally, I'm going to try and keep the tension on the diagonals less than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I put that Loos gauge?) GaryS/V Kaylarah'90 C 37+East Greenwich, RI, USA ~~~_/)~~ On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell wrote: Actually, if you look closely at the manual, you will notice that the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". Since the vertical part of the back stay assembly is rod, I will assume that the 5000 lbs. refers to the vertical. I will go over to the boat tomorrow and try to measure the back stay angle, to see which limit gets exceeded first, the rod or the wire. C could have made this a lot easier. I've got to believe the transom will fail before the wire, yet the wire is all that is specified. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List wrote: Absolutely without any doubt in my mind the backstay tension of 4125 is to be measured on the mainline. This works in opposition to the head stay which is equally sized #12 rod. Josh On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List wrote: Hi Josh, Oops! I missed that. I looked in the chapter about rigging and didn't find it there. Silly me! I even searched for the number 4125 and found nothing. I guess the document is an image rather than text. Now the question, is that the tension in the vertical part of the back stay? I guess, the safest assumption is that it is. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List wrote: Page 68 of the manual pdf file which I linked before has the pre-load and max load limits. Again I am corrected in my preconceived notions regarding the correlation between a hydraulic gauge and the tensile load on the back stay. Josh On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List wrote: Hi Josh, Where did you find the 4125 or 5000 lb. limit? I don't see that in the Owners Manual? Is the 4125 lb. limit for the lower angled segments of the the back stay or the upper vertical part. You can't simply measure the port back stay tension and multiply by two, because of the angle between the two. You would have to measure the angle and apply some trig to get the right value. Mike Cotton's boat was the one I was referring to in my email above. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List wrote: The manual says limit to 4125lbs and then says absolute max of 5000lbs. https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk I never considered that the hydraulic pressure psi could/would be independent of tensile load. When I had my hydraulic pump rebuilt by Lew Townsend he tried to adjust the relief valve but mine adjustment knob was seized. He gave up and just hydro-tested it anyway. He found that the relief was roughly 3500. I rarely go over 2500. Now that I have to consider the corollary between psi and lbs I'll be pulling out my Loose tension gauge and get back to you. Since it is split I'll remember to add together or double a single. As for the attachment to the transom, I agree it does seem slightly poor engineering. In fact when we were shopping around the first boat looked at wad named Blue Pearl and had been owned by Mike Cotton who was and may still be on this list. It was evident that some past event had caused the port aft attachment to separate the flat horizontal (cap) part of the fiberglass casting from the curved (body) potion. The hydraulic pump was a single piston and pump combo that attached between the port anchor amd the port side of the back stay. Evidently a sheave communicated the tension to the stbd size at the point where the single rod attached from the mast head. It seemed as though maybe the sheave didn't roll smoothly and failed to split the tension evenly between the port
Re: Stus-List 37+ Backstay tension
Tom, We're "up there", too. I get it. Gary ~~~_/)~~ On Fri, Aug 3, 2018 at 11:23 AM, Tom Buscaglia via CnC-List < cnc-list@cnc-list.com> wrote: > Gary > > Mainsail tuning on Alera is limited anyway. The in boom furling main has > a rigid vang. So, tuning the mail limited to furling in the main while not > slacking the halyard and using the baby stay to flatten the main. That's > about it for us. But, the ease of two handing with a couple of old farts > is priceless. ;) > > Tom B > > ¤º°`°º¤,¸¸,¤º°`°º¤¤º°`°º¤,¸¸,¤º°`°º¤. > Tom & Lynn Buscaglia > SV Alera > C 37+/40 > Vashon Island WA > (206) 463-9200 > www.sv-alera.com > > > > At 07:31 AM 8/3/2018, you wrote: > > Message: 1 > Date: Fri, 3 Aug 2018 10:20:55 -0400 > From: Gary Russell > To: "C List" > Subject: Re: Stus-List 37+ Backstay tension > Message-ID: > mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Tom, > The back stay with baby stay make a dramatic difference in the > handling and performance of the boat upwind when it starts to blow. I do > agree that the absence of the back stay adjuster reduces stress on the rig > and the captain. I can't imagine the chaos if the back stay attachments > failed. > > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > > ~~~_/)~~ > > . > > > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
Tom, Can you tell me more about your boom furler? Considering one for my 41. Brand, fitment, pix if you can... price if you’re comfortable, too Thanks, Chuck B C 41 Tenacious Somerset, MA Sent from my iPhone > On Aug 3, 2018, at 11:23 AM, Tom Buscaglia via CnC-List > wrote: > > Gary > > Mainsail tuning on Alera is limited anyway. The in boom furling main has a > rigid vang. So, tuning the mail limited to furling in the main while not > slacking the halyard and using the baby stay to flatten the main. That's > about it for us. But, the ease of two handing with a couple of old farts is > priceless. ;) > > Tom B > ¤º°`°º¤,¸¸,¤º°`°º¤¤º°`°º¤,¸¸,¤º°`°º¤. > Tom & Lynn Buscaglia > SV Alera > C 37+/40 > Vashon Island WA > (206) 463-9200 > www.sv-alera.com > > > > At 07:31 AM 8/3/2018, you wrote: > >> Message: 1 >> Date: Fri, 3 Aug 2018 10:20:55 -0400 >> From: Gary Russell >> To: "C List" >> Subject: Re: Stus-List 37+ Backstay tension >> Message-ID: >> >> Content-Type: text/plain; charset="utf-8" >> >> Tom, >> The back stay with baby stay make a dramatic difference in the >> handling and performance of the boat upwind when it starts to blow. I do >> agree that the absence of the back stay adjuster reduces stress on the rig >> and the captain. I can't imagine the chaos if the back stay attachments >> failed. >> >> Gary >> S/V Kaylarah >> '90 C 37+ >> East Greenwich, RI, USA >> >> ~~~_/)~~ > . > > > ___ > > Thanks everyone for supporting this list with your contributions. Each and > every one is greatly appreciated. If you want to support the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
Loos company argues that a loose rig is more likely to damage the boat than a properly tightened one due to shock loading. Without an adjustable backstay you're forced to either keep the rig tight in preparation for max wind or loose to avoid stress while the boat is idle. Or I guess compromise. I don't race and we're almost always double handing with multiple unknowing, unskilled, and uninvolved passengers. I have 3 basic pressures that I apply. ~500 psi - idle boat stored in the slip, backstay is just taught and not slack or sloppy. ~1000 psi - normal sailing up to about 10 kts of wind ~2500 psi - winds above 10 kts, this could get spicy and I don't want to have to remember the stupid backstay. The headsail furler works considerably better with a tight rig and definitely tells me when I've forgotten to pump it up...whether or not I realize what it is telling me is a different story. Josh Muckley S/V Sea Hawk 1989 C 37+ Solomons, MD On Fri, Aug 3, 2018, 10:21 AM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Tom, > The back stay with baby stay make a dramatic difference in the > handling and performance of the boat upwind when it starts to blow. I do > agree that the absence of the back stay adjuster reduces stress on the rig > and the captain. I can't imagine the chaos if the back stay attachments > failed. > > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > > ~~~_/)~~ > > > On Fri, Aug 3, 2018 at 9:27 AM, Tom Buscaglia via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Alera has no backstay tensioner at all. We cruise so it’s not an issue >> and considering the issues re the attachment points I okay with that. >> >> Tom Buscaglia >> S/V Alera >> 1990 C 37+/40 >> Vashon WA >> P 206.463.9200 >> C 305.409.3660 >> >> >> On Aug 3, 2018, at 4:59 AM, cnc-list-requ...@cnc-list.com wrote: >> >> Message: 3 >> Date: Thu, 2 Aug 2018 22:07:57 -0300 >> From: Ken Heaton >> To: cnc-list >> Subject: Re: Stus-List 37+ Backstay tension >> Message-ID: >> >> Content-Type: text/plain; charset="utf-8" >> >> Interesting. All parts of our backstay are rod, the double lowers and the >> single upper. The upper is a larger diameter (as you would expect). Two >> hydraulic rams, one each side. >> >> Some of you have wire for the lower section? >> >> Ken Heaton & Anne Tobin >> S/V Salazar - Can 54955 >> C 37/40 XL - Hull # 67 >> Cape Breton Island, Nova Scotia >> >> https://c-c-37-40.blogspot.ca/p/salazar.html >> >> >> >> On Thu, 2 Aug 2018 at 22:02, Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >> >> ___ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> >> > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
Josh, Great! I would be most interested in the displacement of the hydraulic RAM vs. the Loos gauge tension, since I don't have a working pressure gauge: What would be most interesting to me, would be a table like: Pressure Loos Gauge Displacement of the RAM in inches pounds pounds inches 0 ???0" 500 1000 1500 2000 etc. . I don't actually have a Loos gauge, either, but am trying to borrow one. Thanks, Gary ~~~_/)~~ On Fri, Aug 3, 2018 at 10:21 AM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > With that info I'll head down to my boat and apply various psi to the > hydraulics and then measure the tension with my loos gauge. > > Josh > > On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> So... I went over to Kaylarah this morning and found the following: >> >> The back stay diagonals are 235" long >> The spread between the attachments is 80" >> Doing the math, that means if the maximum tension on the vertical rod is >> 5000 lbs., then the tension on the diagonals is 2537 lbs. >> From here you can apply any safety factor you like, just maintain the >> ration of 2537 : 5000. >> Because the angle between the diagonals is so small (smaller than I >> thought), it is pretty close to 2:1. >> >> Personally, I'm going to try and keep the tension on the diagonals less >> than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I >> put that Loos gauge?) >> >> Gary >> S/V Kaylarah >> '90 C 37+ >> East Greenwich, RI, USA >> >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell >> wrote: >> >>> Actually, if you look closely at the manual, you will notice that >>> the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". >>> Since the vertical part of the back stay assembly is rod, I will assume >>> that the 5000 lbs. refers to the vertical. I will go over to the boat >>> tomorrow and try to measure the back stay angle, to see which limit gets >>> exceeded first, the rod or the wire. C could have made this a lot >>> easier. I've got to believe the transom will fail before the wire, yet the >>> wire is all that is specified. >>> >>> Gary >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Absolutely without any doubt in my mind the backstay tension of 4125 is to be measured on the mainline. This works in opposition to the head stay which is equally sized #12 rod. Josh On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Oops! I missed that. I looked in the chapter about rigging and > didn't find it there. Silly me! I even searched for the number 4125 and > found nothing. I guess the document is an image rather than text. Now the > question, is that the tension in the vertical part of the back stay? I > guess, the safest assumption is that it is. > > Gary > > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Page 68 of the manual pdf file which I linked before has the pre-load >> and max load limits. >> >> Again I am corrected in my preconceived notions regarding the >> correlation between a hydraulic gauge and the tensile load on the back >> stay. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Hi Josh, >>> Where did you find the 4125 or 5000 lb. limit? I don't see >>> that in the Owners Manual? Is the 4125 lb. limit for the lower angled >>> segments of the the back stay or the upper vertical part. You can't >>> simply >>> measure the port back stay tension and multiply by two, because of the >>> angle between the two. You would have to measure the angle and apply >>> some >>> trig to get the right value. Mike Cotton's boat was the one I was >>> referring to in my email above. >>> >>> Gary >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> The manual says limit to 4125lbs and then says absolute max of 5000lbs. https://drive.google.com/file/d/ 0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk I never considered that the hydraulic pressure psi could/would be independent of tensile load. When I had my hydraulic pump rebuilt by Lew Townsend he tried to adjust the relief valve but mine adjustment knob was seized. He gave up and just hydro-tested it anyway. He found that the relief
Re: Stus-List 37+ Backstay tension
With that info I'll head down to my boat and apply various psi to the hydraulics and then measure the tension with my loos gauge. Josh On Fri, Aug 3, 2018, 10:17 AM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > So... I went over to Kaylarah this morning and found the following: > > The back stay diagonals are 235" long > The spread between the attachments is 80" > Doing the math, that means if the maximum tension on the vertical rod is > 5000 lbs., then the tension on the diagonals is 2537 lbs. > From here you can apply any safety factor you like, just maintain the > ration of 2537 : 5000. > Because the angle between the diagonals is so small (smaller than I > thought), it is pretty close to 2:1. > > Personally, I'm going to try and keep the tension on the diagonals less > than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I > put that Loos gauge?) > > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell wrote: > >> Actually, if you look closely at the manual, you will notice that >> the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". >> Since the vertical part of the back stay assembly is rod, I will assume >> that the 5000 lbs. refers to the vertical. I will go over to the boat >> tomorrow and try to measure the back stay angle, to see which limit gets >> exceeded first, the rod or the wire. C could have made this a lot >> easier. I've got to believe the transom will fail before the wire, yet the >> wire is all that is specified. >> >> Gary >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Absolutely without any doubt in my mind the backstay tension of 4125 is >>> to be measured on the mainline. This works in opposition to the head stay >>> which is equally sized #12 rod. >>> >>> Josh >>> >>> On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Hi Josh, Oops! I missed that. I looked in the chapter about rigging and didn't find it there. Silly me! I even searched for the number 4125 and found nothing. I guess the document is an image rather than text. Now the question, is that the tension in the vertical part of the back stay? I guess, the safest assumption is that it is. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > Page 68 of the manual pdf file which I linked before has the pre-load > and max load limits. > > Again I am corrected in my preconceived notions regarding the > correlation between a hydraulic gauge and the tensile load on the back > stay. > > Josh > > On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Hi Josh, >> Where did you find the 4125 or 5000 lb. limit? I don't see that >> in the Owners Manual? Is the 4125 lb. limit for the lower angled >> segments >> of the the back stay or the upper vertical part. You can't simply >> measure >> the port back stay tension and multiply by two, because of the angle >> between the two. You would have to measure the angle and apply some trig >> to get the right value. Mike Cotton's boat was the one I was referring >> to >> in my email above. >> >> Gary >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> The manual says limit to 4125lbs and then says absolute max of >>> 5000lbs. >>> https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk >>> >>> I never considered that the hydraulic pressure psi could/would be >>> independent of tensile load. When I had my hydraulic pump rebuilt by >>> Lew >>> Townsend he tried to adjust the relief valve but mine adjustment knob >>> was >>> seized. He gave up and just hydro-tested it anyway. He found that the >>> relief was roughly 3500. I rarely go over 2500. Now that I have to >>> consider the corollary between psi and lbs I'll be pulling out my Loose >>> tension gauge and get back to you. Since it is split I'll remember to >>> add >>> together or double a single. >>> >>> As for the attachment to the transom, I agree it does seem slightly >>> poor engineering. In fact when we were shopping around the first boat >>> looked at wad named Blue Pearl and had been owned by Mike Cotton who was >>> and may still be on this list. It was evident that some past event had >>> caused the port aft attachment to separate the flat horizontal (cap) >>> part >>> of the fiberglass casting from the curved
Re: Stus-List 37+ Backstay tension
Tom, The back stay with baby stay make a dramatic difference in the handling and performance of the boat upwind when it starts to blow. I do agree that the absence of the back stay adjuster reduces stress on the rig and the captain. I can't imagine the chaos if the back stay attachments failed. Gary S/V Kaylarah '90 C 37+ East Greenwich, RI, USA ~~~_/)~~ On Fri, Aug 3, 2018 at 9:27 AM, Tom Buscaglia via CnC-List < cnc-list@cnc-list.com> wrote: > Alera has no backstay tensioner at all. We cruise so it’s not an issue > and considering the issues re the attachment points I okay with that. > > Tom Buscaglia > S/V Alera > 1990 C 37+/40 > Vashon WA > P 206.463.9200 > C 305.409.3660 > > > On Aug 3, 2018, at 4:59 AM, cnc-list-requ...@cnc-list.com wrote: > > Message: 3 > Date: Thu, 2 Aug 2018 22:07:57 -0300 > From: Ken Heaton > To: cnc-list > Subject: Re: Stus-List 37+ Backstay tension > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > Interesting. All parts of our backstay are rod, the double lowers and the > single upper. The upper is a larger diameter (as you would expect). Two > hydraulic rams, one each side. > > Some of you have wire for the lower section? > > Ken Heaton & Anne Tobin > S/V Salazar - Can 54955 > C 37/40 XL - Hull # 67 > Cape Breton Island, Nova Scotia > > https://c-c-37-40.blogspot.ca/p/salazar.html > > > > On Thu, 2 Aug 2018 at 22:02, Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > > > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
So... I went over to Kaylarah this morning and found the following: The back stay diagonals are 235" long The spread between the attachments is 80" Doing the math, that means if the maximum tension on the vertical rod is 5000 lbs., then the tension on the diagonals is 2537 lbs. >From here you can apply any safety factor you like, just maintain the ration of 2537 : 5000. Because the angle between the diagonals is so small (smaller than I thought), it is pretty close to 2:1. Personally, I'm going to try and keep the tension on the diagonals less than 2000 lbs. which keeps the upper rod below 3942 lbs. (Now where did I put that Loos gauge?) Gary S/V Kaylarah '90 C 37+ East Greenwich, RI, USA ~~~_/)~~ On Thu, Aug 2, 2018 at 9:00 PM, Gary Russell wrote: > Actually, if you look closely at the manual, you will notice that the > 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". > Since the vertical part of the back stay assembly is rod, I will assume > that the 5000 lbs. refers to the vertical. I will go over to the boat > tomorrow and try to measure the back stay angle, to see which limit gets > exceeded first, the rod or the wire. C could have made this a lot > easier. I've got to believe the transom will fail before the wire, yet the > wire is all that is specified. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Absolutely without any doubt in my mind the backstay tension of 4125 is >> to be measured on the mainline. This works in opposition to the head stay >> which is equally sized #12 rod. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Hi Josh, >>> Oops! I missed that. I looked in the chapter about rigging and >>> didn't find it there. Silly me! I even searched for the number 4125 and >>> found nothing. I guess the document is an image rather than text. Now the >>> question, is that the tension in the vertical part of the back stay? I >>> guess, the safest assumption is that it is. >>> >>> Gary >>> >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Page 68 of the manual pdf file which I linked before has the pre-load and max load limits. Again I am corrected in my preconceived notions regarding the correlation between a hydraulic gauge and the tensile load on the back stay. Josh On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Where did you find the 4125 or 5000 lb. limit? I don't see that > in the Owners Manual? Is the 4125 lb. limit for the lower angled segments > of the the back stay or the upper vertical part. You can't simply measure > the port back stay tension and multiply by two, because of the angle > between the two. You would have to measure the angle and apply some trig > to get the right value. Mike Cotton's boat was the one I was referring to > in my email above. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> The manual says limit to 4125lbs and then says absolute max of >> 5000lbs. https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMz >> NnazViYkZzRVRoODlSSUd3/view?usp=drivesdk >> >> I never considered that the hydraulic pressure psi could/would be >> independent of tensile load. When I had my hydraulic pump rebuilt by Lew >> Townsend he tried to adjust the relief valve but mine adjustment knob was >> seized. He gave up and just hydro-tested it anyway. He found that the >> relief was roughly 3500. I rarely go over 2500. Now that I have to >> consider the corollary between psi and lbs I'll be pulling out my Loose >> tension gauge and get back to you. Since it is split I'll remember to >> add >> together or double a single. >> >> As for the attachment to the transom, I agree it does seem slightly >> poor engineering. In fact when we were shopping around the first boat >> looked at wad named Blue Pearl and had been owned by Mike Cotton who was >> and may still be on this list. It was evident that some past event had >> caused the port aft attachment to separate the flat horizontal (cap) part >> of the fiberglass casting from the curved (body) potion. The hydraulic >> pump was a single piston and pump combo that attached between the port >> anchor amd the port side of the back stay. Evidently a sheave >> communicated >> the tension to the stbd size at the point where the single rod attached >> from the mast head. It seemed as though maybe the sheave didn't roll >> smoothly and failed to split the tension evenly
Re: Stus-List 37+ Backstay tension
Alera has no backstay tensioner at all. We cruise so it’s not an issue and considering the issues re the attachment points I okay with that. Tom Buscaglia S/V Alera 1990 C 37+/40 Vashon WA P 206.463.9200 C 305.409.3660 > On Aug 3, 2018, at 4:59 AM, cnc-list-requ...@cnc-list.com wrote: > > Message: 3 > Date: Thu, 2 Aug 2018 22:07:57 -0300 > From: Ken Heaton > To: cnc-list > Subject: Re: Stus-List 37+ Backstay tension > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > Interesting. All parts of our backstay are rod, the double lowers and the > single upper. The upper is a larger diameter (as you would expect). Two > hydraulic rams, one each side. > > Some of you have wire for the lower section? > > Ken Heaton & Anne Tobin > S/V Salazar - Can 54955 > C 37/40 XL - Hull # 67 > Cape Breton Island, Nova Scotia > > https://c-c-37-40.blogspot.ca/p/salazar.html > > > > On Thu, 2 Aug 2018 at 22:02, Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
Interesting. All parts of our backstay are rod, the double lowers and the single upper. The upper is a larger diameter (as you would expect). Two hydraulic rams, one each side. Some of you have wire for the lower section? Ken Heaton & Anne Tobin S/V Salazar - Can 54955 C 37/40 XL - Hull # 67 Cape Breton Island, Nova Scotia https://c-c-37-40.blogspot.ca/p/salazar.html On Thu, 2 Aug 2018 at 22:02, Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Actually, if you look closely at the manual, you will notice that the > 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". > Since the vertical part of the back stay assembly is rod, I will assume > that the 5000 lbs. refers to the vertical. I will go over to the boat > tomorrow and try to measure the back stay angle, to see which limit gets > exceeded first, the rod or the wire. C could have made this a lot > easier. I've got to believe the transom will fail before the wire, yet the > wire is all that is specified. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Absolutely without any doubt in my mind the backstay tension of 4125 is >> to be measured on the mainline. This works in opposition to the head stay >> which is equally sized #12 rod. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Hi Josh, >>> Oops! I missed that. I looked in the chapter about rigging and >>> didn't find it there. Silly me! I even searched for the number 4125 and >>> found nothing. I guess the document is an image rather than text. Now the >>> question, is that the tension in the vertical part of the back stay? I >>> guess, the safest assumption is that it is. >>> >>> Gary >>> >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Page 68 of the manual pdf file which I linked before has the pre-load and max load limits. Again I am corrected in my preconceived notions regarding the correlation between a hydraulic gauge and the tensile load on the back stay. Josh On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Where did you find the 4125 or 5000 lb. limit? I don't see that > in the Owners Manual? Is the 4125 lb. limit for the lower angled segments > of the the back stay or the upper vertical part. You can't simply measure > the port back stay tension and multiply by two, because of the angle > between the two. You would have to measure the angle and apply some trig > to get the right value. Mike Cotton's boat was the one I was referring to > in my email above. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> The manual says limit to 4125lbs and then says absolute max of >> 5000lbs. >> https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk >> >> I never considered that the hydraulic pressure psi could/would be >> independent of tensile load. When I had my hydraulic pump rebuilt by Lew >> Townsend he tried to adjust the relief valve but mine adjustment knob was >> seized. He gave up and just hydro-tested it anyway. He found that the >> relief was roughly 3500. I rarely go over 2500. Now that I have to >> consider the corollary between psi and lbs I'll be pulling out my Loose >> tension gauge and get back to you. Since it is split I'll remember to >> add >> together or double a single. >> >> As for the attachment to the transom, I agree it does seem slightly >> poor engineering. In fact when we were shopping around the first boat >> looked at wad named Blue Pearl and had been owned by Mike Cotton who was >> and may still be on this list. It was evident that some past event had >> caused the port aft attachment to separate the flat horizontal (cap) part >> of the fiberglass casting from the curved (body) potion. The hydraulic >> pump was a single piston and pump combo that attached between the port >> anchor amd the port side of the back stay. Evidently a sheave >> communicated >> the tension to the stbd size at the point where the single rod attached >> from the mast head. It seemed as though maybe the sheave didn't roll >> smoothly and failed to split the tension evenly between the port and stbd >> anchor on the transom. That of the fiberglass layup was uneven and the >> port side was just coincidentally weaker. >> >> I was attentive to this weakness when I continued shopping and found >> Sea Hawk. I discussed the issue with the PO and he showed his >>
Re: Stus-List 37+ Backstay tension
Actually, if you look closely at the manual, you will notice that the 4125 lbs. refers to "wire limit", and 5000 lbs. refers to "rod limit". Since the vertical part of the back stay assembly is rod, I will assume that the 5000 lbs. refers to the vertical. I will go over to the boat tomorrow and try to measure the back stay angle, to see which limit gets exceeded first, the rod or the wire. C could have made this a lot easier. I've got to believe the transom will fail before the wire, yet the wire is all that is specified. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 8:52 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > Absolutely without any doubt in my mind the backstay tension of 4125 is to > be measured on the mainline. This works in opposition to the head stay > which is equally sized #12 rod. > > Josh > > On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Hi Josh, >> Oops! I missed that. I looked in the chapter about rigging and >> didn't find it there. Silly me! I even searched for the number 4125 and >> found nothing. I guess the document is an image rather than text. Now the >> question, is that the tension in the vertical part of the back stay? I >> guess, the safest assumption is that it is. >> >> Gary >> >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Page 68 of the manual pdf file which I linked before has the pre-load >>> and max load limits. >>> >>> Again I am corrected in my preconceived notions regarding the >>> correlation between a hydraulic gauge and the tensile load on the back stay. >>> >>> Josh >>> >>> On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Hi Josh, Where did you find the 4125 or 5000 lb. limit? I don't see that in the Owners Manual? Is the 4125 lb. limit for the lower angled segments of the the back stay or the upper vertical part. You can't simply measure the port back stay tension and multiply by two, because of the angle between the two. You would have to measure the angle and apply some trig to get the right value. Mike Cotton's boat was the one I was referring to in my email above. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > The manual says limit to 4125lbs and then says absolute max of > 5000lbs. https://drive.google.com/file/d/ > 0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk > > I never considered that the hydraulic pressure psi could/would be > independent of tensile load. When I had my hydraulic pump rebuilt by Lew > Townsend he tried to adjust the relief valve but mine adjustment knob was > seized. He gave up and just hydro-tested it anyway. He found that the > relief was roughly 3500. I rarely go over 2500. Now that I have to > consider the corollary between psi and lbs I'll be pulling out my Loose > tension gauge and get back to you. Since it is split I'll remember to add > together or double a single. > > As for the attachment to the transom, I agree it does seem slightly > poor engineering. In fact when we were shopping around the first boat > looked at wad named Blue Pearl and had been owned by Mike Cotton who was > and may still be on this list. It was evident that some past event had > caused the port aft attachment to separate the flat horizontal (cap) part > of the fiberglass casting from the curved (body) potion. The hydraulic > pump was a single piston and pump combo that attached between the port > anchor amd the port side of the back stay. Evidently a sheave > communicated > the tension to the stbd size at the point where the single rod attached > from the mast head. It seemed as though maybe the sheave didn't roll > smoothly and failed to split the tension evenly between the port and stbd > anchor on the transom. That of the fiberglass layup was uneven and the > port side was just coincidentally weaker. > > I was attentive to this weakness when I continued shopping and found > Sea Hawk. I discussed the issue with the PO and he showed his engineering > answer. > > https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM > > I'm not convinced that it is "correct" but it is certainly better than > nothing. I had decided years ago that I was going to engineer a > reinforcement of my own with some G10 FPR. I still have the G10 but have > never acted on the project. My idea was to back the entire corner of the > transom with 1/2" G10 FRP by epoxying it in place and then fill the > attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade > or > mortise
Re: Stus-List 37+ Backstay tension
Absolutely without any doubt in my mind the backstay tension of 4125 is to be measured on the mainline. This works in opposition to the head stay which is equally sized #12 rod. Josh On Thu, Aug 2, 2018, 8:41 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Oops! I missed that. I looked in the chapter about rigging and > didn't find it there. Silly me! I even searched for the number 4125 and > found nothing. I guess the document is an image rather than text. Now the > question, is that the tension in the vertical part of the back stay? I > guess, the safest assumption is that it is. > > Gary > > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Page 68 of the manual pdf file which I linked before has the pre-load and >> max load limits. >> >> Again I am corrected in my preconceived notions regarding the correlation >> between a hydraulic gauge and the tensile load on the back stay. >> >> Josh >> >> On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Hi Josh, >>> Where did you find the 4125 or 5000 lb. limit? I don't see that in >>> the Owners Manual? Is the 4125 lb. limit for the lower angled segments of >>> the the back stay or the upper vertical part. You can't simply measure the >>> port back stay tension and multiply by two, because of the angle between >>> the two. You would have to measure the angle and apply some trig to get >>> the right value. Mike Cotton's boat was the one I was referring to in my >>> email above. >>> >>> Gary >>> >>> ~~~_/)~~ >>> >>> >>> On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> The manual says limit to 4125lbs and then says absolute max of 5000lbs. https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk I never considered that the hydraulic pressure psi could/would be independent of tensile load. When I had my hydraulic pump rebuilt by Lew Townsend he tried to adjust the relief valve but mine adjustment knob was seized. He gave up and just hydro-tested it anyway. He found that the relief was roughly 3500. I rarely go over 2500. Now that I have to consider the corollary between psi and lbs I'll be pulling out my Loose tension gauge and get back to you. Since it is split I'll remember to add together or double a single. As for the attachment to the transom, I agree it does seem slightly poor engineering. In fact when we were shopping around the first boat looked at wad named Blue Pearl and had been owned by Mike Cotton who was and may still be on this list. It was evident that some past event had caused the port aft attachment to separate the flat horizontal (cap) part of the fiberglass casting from the curved (body) potion. The hydraulic pump was a single piston and pump combo that attached between the port anchor amd the port side of the back stay. Evidently a sheave communicated the tension to the stbd size at the point where the single rod attached from the mast head. It seemed as though maybe the sheave didn't roll smoothly and failed to split the tension evenly between the port and stbd anchor on the transom. That of the fiberglass layup was uneven and the port side was just coincidentally weaker. I was attentive to this weakness when I continued shopping and found Sea Hawk. I discussed the issue with the PO and he showed his engineering answer. https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM I'm not convinced that it is "correct" but it is certainly better than nothing. I had decided years ago that I was going to engineer a reinforcement of my own with some G10 FPR. I still have the G10 but have never acted on the project. My idea was to back the entire corner of the transom with 1/2" G10 FRP by epoxying it in place and then fill the attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade or mortise bit to countersink a flat load bearing "pad" for the washers and nuts to drive against and I would be done. Josh Muckley S/V Sea Hawk 1989 C 37+ Solomons, MD On Thu, Aug 2, 2018, 5:53 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Does anyone know the maximum back stay tension allowed on the C > 37+. My problem is the hydraulic back stay adjuster pressure gauge has > failed and I don't even know what the maximum pressure spec allowed is, > anyway. I'm concerned that at least one owner has had the attachment > points on the transom fail presumably due to excessive tension/pressure. > Frankly, the attachment points don't instill a lot of confidence as
Re: Stus-List 37+ Backstay tension
Hi Josh, Oops! I missed that. I looked in the chapter about rigging and didn't find it there. Silly me! I even searched for the number 4125 and found nothing. I guess the document is an image rather than text. Now the question, is that the tension in the vertical part of the back stay? I guess, the safest assumption is that it is. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 8:33 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > Page 68 of the manual pdf file which I linked before has the pre-load and > max load limits. > > Again I am corrected in my preconceived notions regarding the correlation > between a hydraulic gauge and the tensile load on the back stay. > > Josh > > On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Hi Josh, >> Where did you find the 4125 or 5000 lb. limit? I don't see that in >> the Owners Manual? Is the 4125 lb. limit for the lower angled segments of >> the the back stay or the upper vertical part. You can't simply measure the >> port back stay tension and multiply by two, because of the angle between >> the two. You would have to measure the angle and apply some trig to get >> the right value. Mike Cotton's boat was the one I was referring to in my >> email above. >> >> Gary >> >> ~~~_/)~~ >> >> >> On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> The manual says limit to 4125lbs and then says absolute max of 5000lbs. >>> https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNna >>> zViYkZzRVRoODlSSUd3/view?usp=drivesdk >>> >>> I never considered that the hydraulic pressure psi could/would be >>> independent of tensile load. When I had my hydraulic pump rebuilt by Lew >>> Townsend he tried to adjust the relief valve but mine adjustment knob was >>> seized. He gave up and just hydro-tested it anyway. He found that the >>> relief was roughly 3500. I rarely go over 2500. Now that I have to >>> consider the corollary between psi and lbs I'll be pulling out my Loose >>> tension gauge and get back to you. Since it is split I'll remember to add >>> together or double a single. >>> >>> As for the attachment to the transom, I agree it does seem slightly poor >>> engineering. In fact when we were shopping around the first boat looked at >>> wad named Blue Pearl and had been owned by Mike Cotton who was and may >>> still be on this list. It was evident that some past event had caused the >>> port aft attachment to separate the flat horizontal (cap) part of the >>> fiberglass casting from the curved (body) potion. The hydraulic pump was a >>> single piston and pump combo that attached between the port anchor amd the >>> port side of the back stay. Evidently a sheave communicated the tension to >>> the stbd size at the point where the single rod attached from the mast >>> head. It seemed as though maybe the sheave didn't roll smoothly and failed >>> to split the tension evenly between the port and stbd anchor on the >>> transom. That of the fiberglass layup was uneven and the port side was >>> just coincidentally weaker. >>> >>> I was attentive to this weakness when I continued shopping and found Sea >>> Hawk. I discussed the issue with the PO and he showed his engineering >>> answer. >>> >>> https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM >>> >>> I'm not convinced that it is "correct" but it is certainly better than >>> nothing. I had decided years ago that I was going to engineer a >>> reinforcement of my own with some G10 FPR. I still have the G10 but have >>> never acted on the project. My idea was to back the entire corner of the >>> transom with 1/2" G10 FRP by epoxying it in place and then fill the >>> attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade or >>> mortise bit to countersink a flat load bearing "pad" for the washers and >>> nuts to drive against and I would be done. >>> >>> Josh Muckley >>> S/V Sea Hawk >>> 1989 C 37+ >>> Solomons, MD >>> >>> >>> >>> >>> On Thu, Aug 2, 2018, 5:53 PM Gary Russell via CnC-List < >>> cnc-list@cnc-list.com> wrote: >>> Does anyone know the maximum back stay tension allowed on the C 37+. My problem is the hydraulic back stay adjuster pressure gauge has failed and I don't even know what the maximum pressure spec allowed is, anyway. I'm concerned that at least one owner has had the attachment points on the transom fail presumably due to excessive tension/pressure. Frankly, the attachment points don't instill a lot of confidence as there aren't any backing plate; just a couple of holes drilled in the hull. I'd feel more comfortable putting a Loos gauge on the wire and calibrate the extension of the back stay adjuster to it. Any thoughts / ideas out there? Live Slow / Sail Fast, Gary S/V Kaylarah '90 C 37+ East Greenwich, RI, USA ~~~_/)~~
Re: Stus-List 37+ Backstay tension
Page 68 of the manual pdf file which I linked before has the pre-load and max load limits. Again I am corrected in my preconceived notions regarding the correlation between a hydraulic gauge and the tensile load on the back stay. Josh On Thu, Aug 2, 2018, 8:13 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Josh, > Where did you find the 4125 or 5000 lb. limit? I don't see that in > the Owners Manual? Is the 4125 lb. limit for the lower angled segments of > the the back stay or the upper vertical part. You can't simply measure the > port back stay tension and multiply by two, because of the angle between > the two. You would have to measure the angle and apply some trig to get > the right value. Mike Cotton's boat was the one I was referring to in my > email above. > > Gary > > ~~~_/)~~ > > > On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < > cnc-list@cnc-list.com> wrote: > >> The manual says limit to 4125lbs and then says absolute max of 5000lbs. >> https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk >> >> I never considered that the hydraulic pressure psi could/would be >> independent of tensile load. When I had my hydraulic pump rebuilt by Lew >> Townsend he tried to adjust the relief valve but mine adjustment knob was >> seized. He gave up and just hydro-tested it anyway. He found that the >> relief was roughly 3500. I rarely go over 2500. Now that I have to >> consider the corollary between psi and lbs I'll be pulling out my Loose >> tension gauge and get back to you. Since it is split I'll remember to add >> together or double a single. >> >> As for the attachment to the transom, I agree it does seem slightly poor >> engineering. In fact when we were shopping around the first boat looked at >> wad named Blue Pearl and had been owned by Mike Cotton who was and may >> still be on this list. It was evident that some past event had caused the >> port aft attachment to separate the flat horizontal (cap) part of the >> fiberglass casting from the curved (body) potion. The hydraulic pump was a >> single piston and pump combo that attached between the port anchor amd the >> port side of the back stay. Evidently a sheave communicated the tension to >> the stbd size at the point where the single rod attached from the mast >> head. It seemed as though maybe the sheave didn't roll smoothly and failed >> to split the tension evenly between the port and stbd anchor on the >> transom. That of the fiberglass layup was uneven and the port side was >> just coincidentally weaker. >> >> I was attentive to this weakness when I continued shopping and found Sea >> Hawk. I discussed the issue with the PO and he showed his engineering >> answer. >> >> https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM >> >> I'm not convinced that it is "correct" but it is certainly better than >> nothing. I had decided years ago that I was going to engineer a >> reinforcement of my own with some G10 FPR. I still have the G10 but have >> never acted on the project. My idea was to back the entire corner of the >> transom with 1/2" G10 FRP by epoxying it in place and then fill the >> attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade or >> mortise bit to countersink a flat load bearing "pad" for the washers and >> nuts to drive against and I would be done. >> >> Josh Muckley >> S/V Sea Hawk >> 1989 C 37+ >> Solomons, MD >> >> >> >> >> On Thu, Aug 2, 2018, 5:53 PM Gary Russell via CnC-List < >> cnc-list@cnc-list.com> wrote: >> >>> Does anyone know the maximum back stay tension allowed on the C >>> 37+. My problem is the hydraulic back stay adjuster pressure gauge has >>> failed and I don't even know what the maximum pressure spec allowed is, >>> anyway. I'm concerned that at least one owner has had the attachment >>> points on the transom fail presumably due to excessive tension/pressure. >>> Frankly, the attachment points don't instill a lot of confidence as there >>> aren't any backing plate; just a couple of holes drilled in the hull. I'd >>> feel more comfortable putting a Loos gauge on the wire and calibrate the >>> extension of the back stay adjuster to it. Any thoughts / ideas out there? >>> >>> Live Slow / Sail Fast, >>> Gary >>> S/V Kaylarah >>> '90 C 37+ >>> East Greenwich, RI, USA >>> ~~~_/)~~ >>> >>> ___ >>> >>> Thanks everyone for supporting this list with your contributions. Each >>> and every one is greatly appreciated. If you want to support the list - >>> use PayPal to send contribution -- https://www.paypal.me/stumurray >>> >>> >> ___ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> >> >
Re: Stus-List 37+ Backstay tension
Dennis, I agree, and have a "calibrated" batten on mine as well, but I still need the designer to tell me when I am exceeding the design limits of the hard point where the back stay attaches to the transom. Gary S/V Kaylarah '90 C 37+ East Greenwich, RI, USA ~~~_/)~~ On Thu, Aug 2, 2018 at 8:13 PM, Dennis C. via CnC-List < cnc-list@cnc-list.com> wrote: > I never go by lbs, psi, whatever. What matters is sail shape and forestay > sag (or lack thereof). I have a small dinghy batten taped to the AFT side > of the cylinder of the backstay adjuster. On the batten are small wraps of > green, yellow, red and black tape. These are positioned so the fitting on > the backstay will line up with them when the rig is tensioned. On an > upwind leg of a race, we tension the forestay to shape the sail how we like > it, then look at the batten and take note of which tape mark the fitting > lines up with. On the next upwind leg, if the wind and waves are the same, > we tension the rig to the same piece of tape. > > Green = light breeze. Yellow = moderate breeze. Red = heavy breeze. > Black = OMG, we're going to die! > > The tape wraps on the batten are MUCH easier to see than the gauge. > > If you look closely, you can see the batten on the aft side of the > cylinder here: > > https://drive.google.com/open?id=1zzjRreszZF9YCbb5zBfTLGBuVtim4mcZ > > That's not a good picture. It was taken to show the jury rig to tension > the backstay after the adjuster lost the top seal. :( > > Dennis C. > Touche' 35-1 #83 > Mandeville, LA > > On Thu, Aug 2, 2018 at 4:52 PM, Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Does anyone know the maximum back stay tension allowed on the C >> 37+. My problem is the hydraulic back stay adjuster pressure gauge has >> failed and I don't even know what the maximum pressure spec allowed is, >> anyway. I'm concerned that at least one owner has had the attachment >> points on the transom fail presumably due to excessive tension/pressure. >> Frankly, the attachment points don't instill a lot of confidence as there >> aren't any backing plate; just a couple of holes drilled in the hull. I'd >> feel more comfortable putting a Loos gauge on the wire and calibrate the >> extension of the back stay adjuster to it. Any thoughts / ideas out there? >> >> Live Slow / Sail Fast, >> Gary >> S/V Kaylarah >> '90 C 37+ >> East Greenwich, RI, USA >> ~~~_/)~~ >> >> >> ___ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> >> > > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
I never go by lbs, psi, whatever. What matters is sail shape and forestay sag (or lack thereof). I have a small dinghy batten taped to the AFT side of the cylinder of the backstay adjuster. On the batten are small wraps of green, yellow, red and black tape. These are positioned so the fitting on the backstay will line up with them when the rig is tensioned. On an upwind leg of a race, we tension the forestay to shape the sail how we like it, then look at the batten and take note of which tape mark the fitting lines up with. On the next upwind leg, if the wind and waves are the same, we tension the rig to the same piece of tape. Green = light breeze. Yellow = moderate breeze. Red = heavy breeze. Black = OMG, we're going to die! The tape wraps on the batten are MUCH easier to see than the gauge. If you look closely, you can see the batten on the aft side of the cylinder here: https://drive.google.com/open?id=1zzjRreszZF9YCbb5zBfTLGBuVtim4mcZ That's not a good picture. It was taken to show the jury rig to tension the backstay after the adjuster lost the top seal. :( Dennis C. Touche' 35-1 #83 Mandeville, LA On Thu, Aug 2, 2018 at 4:52 PM, Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Does anyone know the maximum back stay tension allowed on the C > 37+. My problem is the hydraulic back stay adjuster pressure gauge has > failed and I don't even know what the maximum pressure spec allowed is, > anyway. I'm concerned that at least one owner has had the attachment > points on the transom fail presumably due to excessive tension/pressure. > Frankly, the attachment points don't instill a lot of confidence as there > aren't any backing plate; just a couple of holes drilled in the hull. I'd > feel more comfortable putting a Loos gauge on the wire and calibrate the > extension of the back stay adjuster to it. Any thoughts / ideas out there? > > Live Slow / Sail Fast, > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > ~~~_/)~~ > > > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
Hi Josh, Where did you find the 4125 or 5000 lb. limit? I don't see that in the Owners Manual? Is the 4125 lb. limit for the lower angled segments of the the back stay or the upper vertical part. You can't simply measure the port back stay tension and multiply by two, because of the angle between the two. You would have to measure the angle and apply some trig to get the right value. Mike Cotton's boat was the one I was referring to in my email above. Gary ~~~_/)~~ On Thu, Aug 2, 2018 at 6:31 PM, Josh Muckley via CnC-List < cnc-list@cnc-list.com> wrote: > The manual says limit to 4125lbs and then says absolute max of 5000lbs. > https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNna > zViYkZzRVRoODlSSUd3/view?usp=drivesdk > > I never considered that the hydraulic pressure psi could/would be > independent of tensile load. When I had my hydraulic pump rebuilt by Lew > Townsend he tried to adjust the relief valve but mine adjustment knob was > seized. He gave up and just hydro-tested it anyway. He found that the > relief was roughly 3500. I rarely go over 2500. Now that I have to > consider the corollary between psi and lbs I'll be pulling out my Loose > tension gauge and get back to you. Since it is split I'll remember to add > together or double a single. > > As for the attachment to the transom, I agree it does seem slightly poor > engineering. In fact when we were shopping around the first boat looked at > wad named Blue Pearl and had been owned by Mike Cotton who was and may > still be on this list. It was evident that some past event had caused the > port aft attachment to separate the flat horizontal (cap) part of the > fiberglass casting from the curved (body) potion. The hydraulic pump was a > single piston and pump combo that attached between the port anchor amd the > port side of the back stay. Evidently a sheave communicated the tension to > the stbd size at the point where the single rod attached from the mast > head. It seemed as though maybe the sheave didn't roll smoothly and failed > to split the tension evenly between the port and stbd anchor on the > transom. That of the fiberglass layup was uneven and the port side was > just coincidentally weaker. > > I was attentive to this weakness when I continued shopping and found Sea > Hawk. I discussed the issue with the PO and he showed his engineering > answer. > > https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM > > I'm not convinced that it is "correct" but it is certainly better than > nothing. I had decided years ago that I was going to engineer a > reinforcement of my own with some G10 FPR. I still have the G10 but have > never acted on the project. My idea was to back the entire corner of the > transom with 1/2" G10 FRP by epoxying it in place and then fill the > attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade or > mortise bit to countersink a flat load bearing "pad" for the washers and > nuts to drive against and I would be done. > > Josh Muckley > S/V Sea Hawk > 1989 C 37+ > Solomons, MD > > > > > On Thu, Aug 2, 2018, 5:53 PM Gary Russell via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Does anyone know the maximum back stay tension allowed on the C >> 37+. My problem is the hydraulic back stay adjuster pressure gauge has >> failed and I don't even know what the maximum pressure spec allowed is, >> anyway. I'm concerned that at least one owner has had the attachment >> points on the transom fail presumably due to excessive tension/pressure. >> Frankly, the attachment points don't instill a lot of confidence as there >> aren't any backing plate; just a couple of holes drilled in the hull. I'd >> feel more comfortable putting a Loos gauge on the wire and calibrate the >> extension of the back stay adjuster to it. Any thoughts / ideas out there? >> >> Live Slow / Sail Fast, >> Gary >> S/V Kaylarah >> '90 C 37+ >> East Greenwich, RI, USA >> ~~~_/)~~ >> >> ___ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
Re: Stus-List 37+ Backstay tension
The manual says limit to 4125lbs and then says absolute max of 5000lbs. https://drive.google.com/file/d/0B8pEh5lnvP1ySXFBdDhrX0ZaMzNnazViYkZzRVRoODlSSUd3/view?usp=drivesdk I never considered that the hydraulic pressure psi could/would be independent of tensile load. When I had my hydraulic pump rebuilt by Lew Townsend he tried to adjust the relief valve but mine adjustment knob was seized. He gave up and just hydro-tested it anyway. He found that the relief was roughly 3500. I rarely go over 2500. Now that I have to consider the corollary between psi and lbs I'll be pulling out my Loose tension gauge and get back to you. Since it is split I'll remember to add together or double a single. As for the attachment to the transom, I agree it does seem slightly poor engineering. In fact when we were shopping around the first boat looked at wad named Blue Pearl and had been owned by Mike Cotton who was and may still be on this list. It was evident that some past event had caused the port aft attachment to separate the flat horizontal (cap) part of the fiberglass casting from the curved (body) potion. The hydraulic pump was a single piston and pump combo that attached between the port anchor amd the port side of the back stay. Evidently a sheave communicated the tension to the stbd size at the point where the single rod attached from the mast head. It seemed as though maybe the sheave didn't roll smoothly and failed to split the tension evenly between the port and stbd anchor on the transom. That of the fiberglass layup was uneven and the port side was just coincidentally weaker. I was attentive to this weakness when I continued shopping and found Sea Hawk. I discussed the issue with the PO and he showed his engineering answer. https://drive.google.com/folderview?id=0B8pEh5lnvP1ybDFIZ0ZZTU1XdHM I'm not convinced that it is "correct" but it is certainly better than nothing. I had decided years ago that I was going to engineer a reinforcement of my own with some G10 FPR. I still have the G10 but have never acted on the project. My idea was to back the entire corner of the transom with 1/2" G10 FRP by epoxying it in place and then fill the attachment cavity (the bump out) with epoxy. Longer u-bolts and a spade or mortise bit to countersink a flat load bearing "pad" for the washers and nuts to drive against and I would be done. Josh Muckley S/V Sea Hawk 1989 C 37+ Solomons, MD On Thu, Aug 2, 2018, 5:53 PM Gary Russell via CnC-List < cnc-list@cnc-list.com> wrote: > Does anyone know the maximum back stay tension allowed on the C > 37+. My problem is the hydraulic back stay adjuster pressure gauge has > failed and I don't even know what the maximum pressure spec allowed is, > anyway. I'm concerned that at least one owner has had the attachment > points on the transom fail presumably due to excessive tension/pressure. > Frankly, the attachment points don't instill a lot of confidence as there > aren't any backing plate; just a couple of holes drilled in the hull. I'd > feel more comfortable putting a Loos gauge on the wire and calibrate the > extension of the back stay adjuster to it. Any thoughts / ideas out there? > > Live Slow / Sail Fast, > Gary > S/V Kaylarah > '90 C 37+ > East Greenwich, RI, USA > ~~~_/)~~ > > ___ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > ___ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
