Headstay tension
- Thread starter Stephen K
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Joe, No problem, It was a legitimate gotcha. I would rather have
a nudge in the ribs over something like that, than be hammered over the head for putting out some bad dope. Happy sailing Joe S
a nudge in the ribs over something like that, than be hammered over the head for putting out some bad dope. Happy sailing Joe S
Just as a 'by the way'
..in checking, your mast tuning it 'appears' that the top of the mast tails off to starboard slightly. Now this may be a result of parallax in the photo or it may be for real but it is worth checking out your rig to see if it's OK.
..in checking, your mast tuning it 'appears' that the top of the mast tails off to starboard slightly. Now this may be a result of parallax in the photo or it may be for real but it is worth checking out your rig to see if it's OK.
Thanks Alan
...it sure does look like it tails to stbd. When I got the new sails, I used my main halyard as a "measuring stick" to the port chainplate and then to the stbd chainplate...the lengths were equal, so I thought I would be in register. Of course at the dock and out in some wind are two different scenarios...it's probably worth checking again...thanks for pointing this out.
...it sure does look like it tails to stbd. When I got the new sails, I used my main halyard as a "measuring stick" to the port chainplate and then to the stbd chainplate...the lengths were equal, so I thought I would be in register. Of course at the dock and out in some wind are two different scenarios...it's probably worth checking again...thanks for pointing this out.
Thanks Don, for the clarification........
but what confused me is how you dismissed the importance of headstay sag and controlling forestay tension with the backstay. We do this all the time. In light to moderate air we use the backstay along with running backs to tighten our forestay and point higher. Forestay sag (to a certain degree) allows the genoa to be fuller and more powerful and gives you a larger groove. That is a great set up when you are sailing in waves or large chop where the power is necessary. But in flat water, once we are up to full speed we shift into higher point mode by tensioning the backstay, and then the runners. The use of the runners helps to keep the mast straight and the main powered up. The flatter entry of the genoa when the backstay is on allows us to point higher until the boat slows down and we power back up again. So in this case we are not using the backstay to bend the rig as you had indicated, and although these are subtle effects, in performance sailing they are very important. While most cruising boats are not set up with runners, the fact that the mast sections are as thick as they are means that it is much more difficult to induce mast bend and flatten the main - so that allows the backstay to be a more handy way to play with forestay tension. Also the amount of mast bend is directly related to how tight your lower shrouds, or in the case of a double spreader rig, your D1 and D2's, are tensioned. I suppose you could use a jib cunningham, but I have only seen them on smaller boats - like we had on our J-24. I can't see how that would work on the larger boats because it seems like you would need a lot of purchase. In the case of the picture posted, I didn't think that the headstay sag looked excessive, and I actually didn't think that the genoa needed trim as it looks to be within 8-10" of the spreader tip. I actually think that what makes the picture look bad is that the boat is pinching allowing the leading edge of the genoa to luff badly. Of course the angles in any photos like these can make things difficult to see. For S. Sauer - I think you would be better off tying the spare halyard to your tack fitting rather than to the bow pulpit to get an indication of how much headstay sag you actually have.
but what confused me is how you dismissed the importance of headstay sag and controlling forestay tension with the backstay. We do this all the time. In light to moderate air we use the backstay along with running backs to tighten our forestay and point higher. Forestay sag (to a certain degree) allows the genoa to be fuller and more powerful and gives you a larger groove. That is a great set up when you are sailing in waves or large chop where the power is necessary. But in flat water, once we are up to full speed we shift into higher point mode by tensioning the backstay, and then the runners. The use of the runners helps to keep the mast straight and the main powered up. The flatter entry of the genoa when the backstay is on allows us to point higher until the boat slows down and we power back up again. So in this case we are not using the backstay to bend the rig as you had indicated, and although these are subtle effects, in performance sailing they are very important. While most cruising boats are not set up with runners, the fact that the mast sections are as thick as they are means that it is much more difficult to induce mast bend and flatten the main - so that allows the backstay to be a more handy way to play with forestay tension. Also the amount of mast bend is directly related to how tight your lower shrouds, or in the case of a double spreader rig, your D1 and D2's, are tensioned. I suppose you could use a jib cunningham, but I have only seen them on smaller boats - like we had on our J-24. I can't see how that would work on the larger boats because it seems like you would need a lot of purchase. In the case of the picture posted, I didn't think that the headstay sag looked excessive, and I actually didn't think that the genoa needed trim as it looks to be within 8-10" of the spreader tip. I actually think that what makes the picture look bad is that the boat is pinching allowing the leading edge of the genoa to luff badly. Of course the angles in any photos like these can make things difficult to see. For S. Sauer - I think you would be better off tying the spare halyard to your tack fitting rather than to the bow pulpit to get an indication of how much headstay sag you actually have.
Stephen
Even if you are using a really high tech halyard which has almost no stretch you really can't get an accurate measure with your halyard. Even more so if your halyard is dacron double braid which stretches greatly. It would be much better to use your halyard to hoist a steel tape for your measurements. If they still come out the same then you may want to check the tension in the cap shrouds. If they are a little on the loose side this will allow the mast tip to tail to leeward. As you have in line spreaders this will not affect the headstay sag but it will affect the main. Rigs that have swept spreaders can control both mast tip tailing and headstay sag at the same time.
Even if you are using a really high tech halyard which has almost no stretch you really can't get an accurate measure with your halyard. Even more so if your halyard is dacron double braid which stretches greatly. It would be much better to use your halyard to hoist a steel tape for your measurements. If they still come out the same then you may want to check the tension in the cap shrouds. If they are a little on the loose side this will allow the mast tip to tail to leeward. As you have in line spreaders this will not affect the headstay sag but it will affect the main. Rigs that have swept spreaders can control both mast tip tailing and headstay sag at the same time.
Clarification
TomD: You are not in the same league as many of the sail trim listers. Most of my stuff is directed towards beginners to low intermediates and a lot of them have no idea what runners even are. At the point they are at from a sail trim stand point is they raise the main and roll out the jib and call it sailing - some even call it racing. So for these people I do dismiss the back stay adjuster. All they will get out of it is more weather helm. Additionally, if they have a loose forestay they should tighten it up. On a jib cunnigham - I had one on my Catalina 30 and think it is the only way to go as opposed to using the jib halyard. It is a much easier way to adjust draft depth and draft position. I know what you are talking about as do listers like Alan, Joe from San diego and Stu along with some others but a lot of the other folks have a way to go with the basics before they get to your level.
TomD: You are not in the same league as many of the sail trim listers. Most of my stuff is directed towards beginners to low intermediates and a lot of them have no idea what runners even are. At the point they are at from a sail trim stand point is they raise the main and roll out the jib and call it sailing - some even call it racing. So for these people I do dismiss the back stay adjuster. All they will get out of it is more weather helm. Additionally, if they have a loose forestay they should tighten it up. On a jib cunnigham - I had one on my Catalina 30 and think it is the only way to go as opposed to using the jib halyard. It is a much easier way to adjust draft depth and draft position. I know what you are talking about as do listers like Alan, Joe from San diego and Stu along with some others but a lot of the other folks have a way to go with the basics before they get to your level.
Tight leech
Stephen - just a thought, but I wonder if the attachment point of the clew could be such that the leech gets pulled more than the body of the sail. Do you know what I mean? For example, if it was attached close to the edge over the leech pocket such that it pulls on the tape and pocket, compared to a bit more forward where it would have a good even grab on the sail. I think looking at the clew (take a picture) under sail would answer this question. I don't have a sail at home to look at, so I might be out to lunch...
Stephen - just a thought, but I wonder if the attachment point of the clew could be such that the leech gets pulled more than the body of the sail. Do you know what I mean? For example, if it was attached close to the edge over the leech pocket such that it pulls on the tape and pocket, compared to a bit more forward where it would have a good even grab on the sail. I think looking at the clew (take a picture) under sail would answer this question. I don't have a sail at home to look at, so I might be out to lunch...
I think I understand...
Rick, I think I understand what you are saying.... my clew has the standard "ring" that is mounted in that corner of the sail. The ring is forward of the "leech pocket" and leech line. I don't think that's adding tension on the leech line, but its a good point. I didn't find any points where the leech line was stitched...so the sail was sent back today and should be at the sailmaker on Monday...more to follow.
Rick, I think I understand what you are saying.... my clew has the standard "ring" that is mounted in that corner of the sail. The ring is forward of the "leech pocket" and leech line. I don't think that's adding tension on the leech line, but its a good point. I didn't find any points where the leech line was stitched...so the sail was sent back today and should be at the sailmaker on Monday...more to follow.
Almost...
I was thinking the position of the attachment to the clew could be pulling on the leech edge or leech pocket itself, not the leech line that you may well find is running freely in the pocket. From memory, my clew ring is attached by a single strip of maybe 1" webbing. If you call the sail a 90 degree angle at the clew, then the strip is sewn to the port side foot of the sail just forward of the point at the clew. Then it goes through the ring with a single bend to make about a 45 degree V, and the other end is sewn to the leech of the sail _above_ the point at the clew. I'm picturing the upper attachment of this strap pulling on the leech pocket somehow more than it pulls on the body of the sail. One could only tell by looking at it under load as in your picture.
I was thinking the position of the attachment to the clew could be pulling on the leech edge or leech pocket itself, not the leech line that you may well find is running freely in the pocket. From memory, my clew ring is attached by a single strip of maybe 1" webbing. If you call the sail a 90 degree angle at the clew, then the strip is sewn to the port side foot of the sail just forward of the point at the clew. Then it goes through the ring with a single bend to make about a 45 degree V, and the other end is sewn to the leech of the sail _above_ the point at the clew. I'm picturing the upper attachment of this strap pulling on the leech pocket somehow more than it pulls on the body of the sail. One could only tell by looking at it under load as in your picture.
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