I don't know what I am doing wrong. Based on what I have read, I fiugre I should have around 3-5" of rake and 2-3" of pre bend on my 240. Last night I decided I was going to fix the tuning once and for all. I loosened the whole rig and started tightening the forestay. FYI I have the CDI roller furler, and my mast is a US Spar. I tightend the forestay as far as it would go and had about 4" of and 6+" of rake. BUT I still had to tighten the uppers which will add to both. By the time I finished I have 6" of pre bend and 8-9" of rake. Any ideas? Nathan
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Tom Wootton
Same problem on a H26
I've done exactly what you describe, with similar results (2-3" prebend, 10" rake). I don't have roller furling, but plan to add it soon. I'm debating whether to shorten the forestay at that time. Since I have little basis for comparison, I don't know whether my weather helm is "excessive" or not. It occurred to me that further tightening the lower shrouds might reduce both prebend and rake, since the uppers don't go to the masthead, but my prebend is pretty close to spec already. That might work for you, though.
I've done exactly what you describe, with similar results (2-3" prebend, 10" rake). I don't have roller furling, but plan to add it soon. I'm debating whether to shorten the forestay at that time. Since I have little basis for comparison, I don't know whether my weather helm is "excessive" or not. It occurred to me that further tightening the lower shrouds might reduce both prebend and rake, since the uppers don't go to the masthead, but my prebend is pretty close to spec already. That might work for you, though.
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Michael C.
Look for...
...the excellent tuning procedure posted here previously. You should be able to find it in the archives. Are you measuring rake before or after bending the mast? Is your boat on the trailer? If so, is it level? In the case of the furler, was the forestay properly shortened when the furler was installed? Make sure everything is right before you shorten the forestay - it's not so easy to make it longer... Michael C. Windswept 'H26
...the excellent tuning procedure posted here previously. You should be able to find it in the archives. Are you measuring rake before or after bending the mast? Is your boat on the trailer? If so, is it level? In the case of the furler, was the forestay properly shortened when the furler was installed? Make sure everything is right before you shorten the forestay - it's not so easy to make it longer... Michael C. Windswept 'H26
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Nathan Schaan
Can't get bend out
Michael, Apprciate your thoughts you may have hit on something here. I can't get the prebend out as my diagonals are as loose as they go and I still have bend of 3-4". Maybe the diagonals need to be longer? Nathan
Michael, Apprciate your thoughts you may have hit on something here. I can't get the prebend out as my diagonals are as loose as they go and I still have bend of 3-4". Maybe the diagonals need to be longer? Nathan
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John
All that it can go?
Nathan, you mentioned that the forestay was tightened "as far as it would go". What do you mean? If I read it correctly, the Hunter instruction said to tighten the forestay to half way then addjust other standing rigging. As you found out, there is going to be an additional bending of the mast as the uppers are adjusted.
Nathan, you mentioned that the forestay was tightened "as far as it would go". What do you mean? If I read it correctly, the Hunter instruction said to tighten the forestay to half way then addjust other standing rigging. As you found out, there is going to be an additional bending of the mast as the uppers are adjusted.
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Tom Wootton
Nathan...
...maybe the H24 is different from the H26, but if by "diagonals" you mean the lower shrouds (the ones that connect to the mast just under the spreaders), then tightening them should REDUCE prebend. Tightening the lower shrouds should pull the mast aft at the spreaders, while the forestay connection point, which is higher up the mast (but not all the way up), will stay fixed, as will the mast base. That could reduce your prebend AND your rake. I think I'll recheck the tension on my own lowers, now that I think of it.
...maybe the H24 is different from the H26, but if by "diagonals" you mean the lower shrouds (the ones that connect to the mast just under the spreaders), then tightening them should REDUCE prebend. Tightening the lower shrouds should pull the mast aft at the spreaders, while the forestay connection point, which is higher up the mast (but not all the way up), will stay fixed, as will the mast base. That could reduce your prebend AND your rake. I think I'll recheck the tension on my own lowers, now that I think of it.
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Nathan
Diagonals
The diagonals atach from the spreadres to the mast. They are not the lowers. Thanks for your help. NS
The diagonals atach from the spreadres to the mast. They are not the lowers. Thanks for your help. NS
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Wayne
240 tuning
Will check my 240 this weekend. During my first season I could not get the rake any closure than around 8-10 inches by memory, prebend seemed fine and sailed quite well. I bought a loose gauge (sp) which helped me get the inner/outer right and everything seemed to settle down. Without the gauge it was tough to guess tentions.
Will check my 240 this weekend. During my first season I could not get the rake any closure than around 8-10 inches by memory, prebend seemed fine and sailed quite well. I bought a loose gauge (sp) which helped me get the inner/outer right and everything seemed to settle down. Without the gauge it was tough to guess tentions.
Mast tuning
The H23.5 and H240 have a mast section and swept-back spreaders similar to the H23. With the standing rigging slack you can easily bend the mast with just the force of your hand. This is the heart of the famous "bendy" rig, which is highly tunable and will do all kinds of wonderful things for your sail trim if you have an adjustable backstay (like I do). When the upper shrouds are tensioned, the swept-back spreaders bend the middle of the mast forward like a bow. Note that the top of the mast is restrained by the forestay and does NOT move. The lower shrouds oppose the bow action, as they are connected to the mast at the base of the spreaders. If you tension the uppers with the lowers slack, there is no resistance, and you can put some serious prebend into the mast without seeing a big increase in upper shroud tension. The trick is to tension the uppers until you have about 2/3 of the prebend you need, then tighten the lowers to the specified tension (usually 10 to 12% of the wire breaking strength). Now go back and finish tightening the uppers. You will find that the tension now increases faster than before. More importantly the mast will not bend much more. Peter H23 "Raven"
The H23.5 and H240 have a mast section and swept-back spreaders similar to the H23. With the standing rigging slack you can easily bend the mast with just the force of your hand. This is the heart of the famous "bendy" rig, which is highly tunable and will do all kinds of wonderful things for your sail trim if you have an adjustable backstay (like I do). When the upper shrouds are tensioned, the swept-back spreaders bend the middle of the mast forward like a bow. Note that the top of the mast is restrained by the forestay and does NOT move. The lower shrouds oppose the bow action, as they are connected to the mast at the base of the spreaders. If you tension the uppers with the lowers slack, there is no resistance, and you can put some serious prebend into the mast without seeing a big increase in upper shroud tension. The trick is to tension the uppers until you have about 2/3 of the prebend you need, then tighten the lowers to the specified tension (usually 10 to 12% of the wire breaking strength). Now go back and finish tightening the uppers. You will find that the tension now increases faster than before. More importantly the mast will not bend much more. Peter H23 "Raven"
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