Re: [Cal_Boats] Forestay tension

Gauges are fine but the real world will prevail! Your jib is cut to take forestay sag into consideration. fore stay sag on a 36 foot boat will be in the 4to 8 inch range. When you are sailing to windward in 18k true get out on the bow pulpit and sight up the forestay . you can sight the deflection. To change this deflection , tighten the forestay and the backstay. at some point you will bend the boat so some degree of prudence is called for.. Your sailmaker has provided for this sag and you will not be able to have a bar tight stay in any conditions. Bending your mast ( Putting a curve in it ) will pull draft out of the M'sl and will work better to windward No big deal! Every body cares, masts are expensive, Keep it in column. My Best, Mike --- On Fri, 6/26/09, Allen Edwards <al… [at] PaloAltoPhoto.com> wrote: From: Allen Edwards <al… [at] PaloAltoPhoto.com> Subject: [Cal_Boats] Forestay tension To: Ca… [at] yahoogroups.com Date: Friday, June 26, 2009, 5:40 PM I have completed my measurement of forestay tension on my L-36. My conclusion is that the Loos PT-2 is not very accurate at high readings on 1/4 inch wire but the PT-3 is accurate. The final measurements were made with a bathroom scale and a lever to that I got about a 10:1 transfer to the scale and could thus read the tension off the bathroom scale. I also made measurement using the stretch charcteristics of the wire and got basically the same result as with the scale. If anyone has any input on what I have done, please chime in. You all with your aluminum masts probably don't care as much as I do with my wood mast but I pass it on in case it may be of interest. http://l-36.com/loosaccuracy.php Just for reference on turning a Cal rig. I offer the instructions from several of the manuals: http://l-36.com/rigtune.php And a letter from Bill Lapworth on the subject http://l-36.com/lapworth_letter.pdf Cheers, Allen

I guess I should have said I did this because I was trying to keep the forestay tension below 18% of breaking strength or 1300 pounds which was 12 turns according to the gauge. Being conservative, I backed off a couple of turns and used 10. But I couldn't point worth a damn and lost a race I have been trying to win to another L-36. Forestay tension was one of a long list of things I have worked on and now I can sail higher and faster than most boats in our beer can races, which I am using as practice. In fact, I ran down a C&C-41 the other evening. We were to leeward and well behind him on a beat and passed him to windward with a 5 boat length separation. That is a boat that has to give us over a minute per mile! So, increasing the tension was one factor but only one. To get to my target of 1300 pounds, I would have to put 15 turns on so I was well backed off at 10. I understand what you are saying about forestay sag and think that 1 finger width at arms length is about the right deflection if you put your eyeball up against the forestay at the tack. My overwhelming concern however remains not breaking my mast. Allen On Fri, Jun 26, 2009 at 7:38 PM, mike farrell <ve… [at] yahoo.com> wrote: > > > Gauges are fine but the real world will prevail! Your jib is cut to take > forestay sag into consideration. fore stay sag on a 36 foot boat will be in > the 4to 8 inch range. When you are sailing to windward in 18k true get out > on the bow pulpit and sight up the forestay . you can sight the deflection. > To change this deflection , tighten the forestay and the backstay. at some > point you will bend the boat so some degree of prudence is called for. Your > sailmaker has provided for this sag and you will not be able to have a bar > tight stay in any conditions. Bending your mast ( Putting a curve in it ) > will pull draft out of the M'sl and will work better to windward No big > deal! Every body cares, masts are expensive, Keep it in column. > My Best, Mike > --- On *Fri, 6/26/09, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: > > > From: Allen Edwards <al… [at] PaloAltoPhoto.com> > Subject: [Cal_Boats] Forestay tension > To: Ca… [at] yahoogroups.com > Date: Friday, June 26, 2009, 5:40 PM > > > > > I have completed my measurement of forestay tension on my L-36. My > conclusion is that the Loos PT-2 is not very accurate at high readings on > 1/4 inch wire but the PT-3 is accurate. The final measurements were made > with a bathroom scale and a lever to that I got about a 10:1 transfer to the > scale and could thus read the tension off the bathroom scale. I also made > measurement using the stretch charcteristics of the wire and got basically > the same result as with the scale. If anyone has any input on what I have > done, please chime in. > > You all with your aluminum masts probably don't care as much as I do with > my wood mast but I pass it on in case it may be of interest. > http://l-36.com/loosaccuracy.php > > Just for reference on turning a Cal rig. I offer the instructions from > several of the manuals: > http://l-36.com/rigtune.php > > And a letter from Bill Lapworth on the subject > http://l-36.com/lapworth_letter.pdf > > Cheers, > > Allen > > > > >

Allen, if you have a chute, you can take the spin hal and attach it to the middle of the bow pulpit, and pull it tight. You can the see the forestay sag very readily ginf to windward as compared to the spin hal on the pulpit. Depending on the jib cut, you would be surprised how much sag works well. Cheers Charlie From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Allen Edwards Sent: Friday, June 26, 2009 11:35 PM To: Ca… [at] yahoogroups.com Subject: Re: [Cal_Boats] Forestay tension I guess I should have said I did this because I was trying to keep the forestay tension below 18% of breaking strength or 1300 pounds which was 12 turns according to the gauge. Being conservative, I backed off a couple of turns and used 10. But I couldn't point worth a damn and lost a race I have been trying to win to another L-36. Forestay tension was one of a long list of things I have worked on and now I can sail higher and faster than most boats in our beer can races, which I am using as practice. In fact, I ran down a C&C-41 the other evening. We were to leeward and well behind him on a beat and passed him to windward with a 5 boat length separation. That is a boat that has to give us over a minute per mile! So, increasing the tension was one factor but only one. To get to my target of 1300 pounds, I would have to put 15 turns on so I was well backed off at 10. I understand what you are saying about forestay sag and think that 1 finger width at arms length is about the right deflection if you put your eyeball up against the forestay at the tack. My overwhelming concern however remains not breaking my mast. Allen On Fri, Jun 26, 2009 at 7:38 PM, mike farrell <ve… [at] yahoo.com<mailto:ve… [at] yahoo.com>> wrote: Gauges are fine but the real world will prevail! Your jib is cut to take forestay sag into consideration. fore stay sag on a 36 foot boat will be in the 4to 8 inch range. When you are sailing to windward in 18k true get out on the bow pulpit and sight up the forestay . you can sight the deflection. To change this deflection , tighten the forestay and the backstay. at some point you will bend the boat so some degree of prudence is called for. Your sailmaker has provided for this sag and you will not be able to have a bar tight stay in any conditions. Bending your mast ( Putting a curve in it ) will pull draft out of the M'sl and will work better to windward No big deal! Every body cares, masts are expensive, Keep it in column. My Best, Mike --- On Fri, 6/26/09, Allen Edwards <al… [at] PaloAltoPhoto.com> wrote: From: Allen Edwards <al… [at] PaloAltoPhoto.com> Subject: [Cal_Boats] Forestay tension To: Ca… [at] yahoogroups.com<mailto:Ca… [at] yahoogroups.com> Date: Friday, June 26, 2009, 5:40 PM I have completed my measurement of forestay tension on my L-36. My conclusion is that the Loos PT-2 is not very accurate at high readings on 1/4 inch wire but the PT-3 is accurate. The final measurements were made with a bathroom scale and a lever to that I got about a 10:1 transfer to the scale and could thus read the tension off the bathroom scale. I also made measurement using the stretch charcteristics of the wire and got basically the same result as with the scale. If anyone has any input on what I have done, please chime in. You all with your aluminum masts probably don't care as much as I do with my wood mast but I pass it on in case it may be of interest. http://l-36.com/loosaccuracy.php Just for reference on turning a Cal rig. I offer the instructions from several of the manuals: http://l-36.com/rigtune.php And a letter from Bill Lapworth on the subject http://l-36.com/lapworth_letter.pdf Cheers, Allen

That is a good idea. I will have to try the spin halyard idea. I calculated the finger measurement just because I always have it with me :-) A finger is .75 inches and my arm is 2 feet. If half way up my forestay is about 20 feet, a finger would cover about 7.5 inches so if you put your eye on the forestay at the tack and see if the sag is a finger width you get a measurement. I guess that would be the outside of what people consider acceptable sag. I think I should be able to use the same calibrated finger with the spin halyard and get a more accurate reading. One of the issues around here is that there is often a lot of wind so the idea in sailing fast is to reduce power without changing sails. We race without spinnakers so there isn't a good way to change and most of the legs are reaches. However, the beat is very important and makes the difference in who wins. But with 20 knots of wind, a 155 jib and a full roach main more power isn't always what you want. Learning to depower is very important around here. In the beer can race the other day we were the fastest boat upwind out there. We sailed with the main flogging, and the windward jib tell tail flying straight up all the time. My crew would yell out the heel angle and when they yelled 40 degrees, I would head up even more. (25 is the goal). When we got back to the slip we made notes of other things we should have done to depower. Jib car back more, put jib halyard tension on before the mark (so you can actually tighten it). Get a heel gauge I can read from the rail while at the helm. But in spite of all that, we were really fast and passed 6 of the 7 boats that were in front of us and most of them had much lower handicaps. They got in front of us because we don't use a spinnaker and they do plus we picked the no wind path on the downwind leg that day but that is another story. So, things are improving and Lapworth was one great designer. Anyway, thanks for the suggestion. Oh, I forgot to mention, the other L-36 that I race against (and find it very hard to beat) has an aluminum rig and puts 3400 pounds of backstay tension on which is 5000 pounds on the forestay. Now, he is measuring under load and I am measuring at the slip but 5000 pounds would permanently deform my forestay. His is the next wire up but it is still a huge load. That is really what started the halyard tension part of my pointing investigation. Allen On Fri, Jun 26, 2009 at 9:43 PM, Husar, Charlie [USA] <hu… [at] bah.com > wrote: > > > Allen, if you have a chute, you can take the spin hal and attach it to > the middle of the bow pulpit, and pull it tight. You can the see the > forestay sag very readily ginf to windward as compared to the spin hal on > the pulpit. > > Depending on the jib cut, you would be surprised how much sag works well. > > Cheers > Charlie > > ------------------------------ > *From:* Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] *On > Behalf Of *Allen Edwards > *Sent:* Friday, June 26, 2009 11:35 PM > *To:* Ca… [at] yahoogroups.com > *Subject:* Re: [Cal_Boats] Forestay tension > > I guess I should have said I did this because I was trying to keep the > forestay tension below 18% of breaking strength or 1300 pounds which was 12 > turns according to the gauge. Being conservative, I backed off a couple of > turns and used 10. But I couldn't point worth a damn and lost a race I have > been trying to win to another L-36. Forestay tension was one of a long list > of things I have worked on and now I can sail higher and faster than most > boats in our beer can races, which I am using as practice. In fact, I ran > down a C&C-41 the other evening. We were to leeward and well behind him on > a beat and passed him to windward with a 5 boat length separation. That is > a boat that has to give us over a minute per mile! So, increasing the > tension was one factor but only one. To get to my target of 1300 pounds, I > would have to put 15 turns on so I was well backed off at 10. I understand > what you are saying about forestay sag and think that 1 finger width at arms > length is about the right deflection if you put your eyeball up against the > forestay at the tack. My overwhelming concern however remains not breaking > my mast. > > Allen > > > On Fri, Jun 26, 2009 at 7:38 PM, mike farrell <ve… [at] yahoo.com>wrote: > >> >> >> Gauges are fine but the real world will prevail! Your jib is cut to >> take forestay sag into consideration. fore stay sag on a 36 foot boat will >> be in the 4to 8 inch range. When you are sailing to windward in 18k true >> get out on the bow pulpit and sight up the forestay . you can sight the >> deflection. To change this deflection , tighten the forestay and the >> backstay. at some point you will bend the boat so some degree of prudence is >> called for. Your sailmaker has provided for this sag and you will not be >> able to have a bar tight stay in any conditions. Bending your mast ( Putting >> a curve in it ) will pull draft out of the M'sl and will work better to >> windward No big deal! Every body cares, masts are expensive, Keep it in >> column. >> My Best, Mike >> --- On *Fri, 6/26/09, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: >> >> >> From: Allen Edwards <al… [at] PaloAltoPhoto.com> >> Subject: [Cal_Boats] Forestay tension >> To: Ca… [at] yahoogroups.com >> Date: Friday, June 26, 2009, 5:40 PM >> >> >> >> >> I have completed my measurement of forestay tension on my L-36. My >> conclusion is that the Loos PT-2 is not very accurate at high readings on >> 1/4 inch wire but the PT-3 is accurate. The final measurements were made >> with a bathroom scale and a lever to that I got about a 10:1 transfer to the >> scale and could thus read the tension off the bathroom scale. I also made >> measurement using the stretch charcteristics of the wire and got basically >> the same result as with the scale. If anyone has any input on what I have >> done, please chime in. >> >> You all with your aluminum masts probably don't care as much as I do with >> my wood mast but I pass it on in case it may be of interest. >> http://l-36.com/loosaccuracy.php >> >> Just for reference on turning a Cal rig. I offer the instructions from >> several of the manuals: >> http://l-36.com/rigtune.php >> >> And a letter from Bill Lapworth on the subject >> http://l-36.com/lapworth_letter.pdf >> >> Cheers, >> >> Allen >> >> >> >> > >