WILL SOMEONE PLEASE EXPLAIN THE RATIONAL FOR TIGHTENING STAYS AND SHROUDS TO THE POINT WHERE THEY "TWANG" I TIGHTEN MY TURNBUCKLES SO THAT THE STAYS AND SHROUDS ARE JUST TAUT AND YES THE SHROUDS ON THE LEEWARD SIDE DO SHOW A LITTLE SLACK IN A GOOD BREEZE BUT SO WHAT ,THE WINDWARD STAYS SNUG UP TIGHT AND KEEP THE MAST WHERE IT BELONGS. MAYBE I'M WRONG, IF SO PLEASE EXPLAIN WHY
DONJOECAM@AOL.CON
MAST UNING
Moderator: Jim Walsh
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Mike Wainfeld
Re: MAST UNING
To prevent "shock loading" of the leeward shroud on a tack. If the shroud is slack, the mast has room to move to leeward until its motion is suddenly stopped as the shoud comes tight. This "shock" load is more forceful than if some tension remained on the shroud throughout the tack.
ripcord1@erols.com
ripcord1@erols.com
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Russ Campbell
Re: MAST UNING
I am of the opinion that many people overtighten their stays. The shrouds should be a little loose on the leeward side in a good blow. If you overtighten them you tend to drive the mast right through the boat and this produces the deck crazing around the mast step. In my opinion you have it right. Just tighten them up to where the mast stays in line and the leeward shrouds are just a little loose.
Russ
camroll@together.net
Russ
WILL SOMEONE PLEASE EXPLAIN THE RATIONAL FOR TIGHTENING STAYS AND SHROUDS TO THE POINT WHERE THEY "TWANG" I TIGHTEN MY TURNBUCKLES SO THAT THE STAYS AND SHROUDS ARE JUST TAUT AND YES THE SHROUDS ON THE LEEWARD SIDE DO SHOW A LITTLE SLACK IN A GOOD BREEZE BUT SO WHAT ,THE WINDWARD STAYS SNUG UP TIGHT AND KEEP THE MAST WHERE IT BELONGS. MAYBE I'M WRONG, IF SO PLEASE EXPLAIN WHY
camroll@together.net
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Dana
Re: TUNING the Standing Rig
+++++++++++++++++++++++++++++++++++++++++++++++++++++++WILL SOMEONE PLEASE EXPLAIN THE RATIONAL FOR TIGHTENING STAYS AND SHROUDS TO THE POINT WHERE THEY "TWANG" I TIGHTEN MY TURNBUCKLES SO THAT THE STAYS AND SHROUDS ARE JUST TAUT AND YES THE SHROUDS ON THE LEEWARD SIDE DO SHOW A LITTLE SLACK IN A GOOD BREEZE BUT SO WHAT ,THE WINDWARD STAYS SNUG UP TIGHT AND KEEP THE MAST WHERE IT BELONGS. MAYBE I'M WRONG, IF SO PLEASE EXPLAIN WHY
This is, of course, one of the least discussed or understood subject among sailors. Just pick up most sailing books and try to find any information.....
Anyway, two opposite schools of thoughts....boat builders vs. wire manufacturers. Wire manufacturers want tensions just under wire normal working loads (for size) for life of wire. Boat builders do not want to overstress the hull structure with excess loads from such loads. Sailor left in the middle. I have tried the wire manufacturers numbers (twang) but these are too stressful. I have decided on tensions which are approx 75% of recommended tension values based on application and size...i.e shroud vs. stay etc. and wire diameter. It probably gives tensions, under sail, just slightly above your description. I use the LOOS gauges to do the adjustments on my CD26.
darenius@aol.com
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DON C
Re: MAST UNING
COMMENT ON MIKE WAINFELD'S RESPONSE--IF THE TENSION OF THE STAYS IS ADJUSTABLE BY MEANS OF TURNBUCKLES IT SEEMS TO ME THAT THE WIRE ROPE MUST BE SOMEWHAT STRETCHABLE AND THEREFORE WHEN TACKING WITH STAYS JUST TAUT THE LOAD ON THE WINDWARD STAYS IS ADDED PROGRESSIVELY (EVEN THOUGH QUICKLY) UNTIL THE LIMIT OF STRETCH OF THE CABLE IS REACHED, THE STRETCH FACTOR ACTING AS A SHOCK ABSORBER. I ALSO WONDER WHETHER STAYS AND SHROUDS WHICH ARE SET, AND PERIODICALLY RESET REAL TIGHT TO MAINTAIN TENSION SETTINGS, MIGHT EVENTUALLY LOSE ALL STRETCHABILITY AND DEVELOP METAL FATIGUE.
DONJOECAM@AOL.COM
DONJOECAM@AOL.COM
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Mike Wainfeld
Re: MAST UNING
Don-
Check my post from a couple of weeks ago on this subject. As Dana says there's not a whole lot of published info out there on this topic.
You don't have to have your shrouds that tight to get a musical note; mine are definitely NOT "bar" tight. I think about 250-300 on the Loos tension gauge. And my lee shrouds are a little loose when sailing close-hauled, just not flopping. On the other hand, America's Cup boats have ther standing rig tightened to the max, which is OK as long as they have the engineering to support that tension (witness the Australian boat breaking in half several years ago) The brochure that came with the Loos gauge was probably the most practical advice I have seen on this subject.
Mike Wainfeld
CD Typhoon "Regalo"
ripcord1@erols.com
Check my post from a couple of weeks ago on this subject. As Dana says there's not a whole lot of published info out there on this topic.
You don't have to have your shrouds that tight to get a musical note; mine are definitely NOT "bar" tight. I think about 250-300 on the Loos tension gauge. And my lee shrouds are a little loose when sailing close-hauled, just not flopping. On the other hand, America's Cup boats have ther standing rig tightened to the max, which is OK as long as they have the engineering to support that tension (witness the Australian boat breaking in half several years ago) The brochure that came with the Loos gauge was probably the most practical advice I have seen on this subject.
Mike Wainfeld
CD Typhoon "Regalo"
ripcord1@erols.com
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Don Carr
Re: MAST UNING
Actually I have tried both ways and found adverse weather helm. Here is a tip..start with the recommendations in the CD25 owners guide. I found that following those suggestions the boat is far better balanced and sails far better than setting the stays in the manner of a high performance boat. Remember most performance boats are not stayed with full foward and aft lowers and most are running some type of fractional rig.WILL SOMEONE PLEASE EXPLAIN THE RATIONAL FOR TIGHTENING STAYS AND SHROUDS TO THE POINT WHERE THEY "TWANG" I TIGHTEN MY TURNBUCKLES SO THAT THE STAYS AND SHROUDS ARE JUST TAUT AND YES THE SHROUDS ON THE LEEWARD SIDE DO SHOW A LITTLE SLACK IN A GOOD BREEZE BUT SO WHAT ,THE WINDWARD STAYS SNUG UP TIGHT AND KEEP THE MAST WHERE IT BELONGS. MAYBE I'M WRONG, IF SO PLEASE EXPLAIN WHY
carrd@erols.com
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Matt Cawthorne
Re: Tuning the rig.
Don,
I am not sure which boat you have and the rigs vary a bit. I generally agree that the wires should not be "bar taught". The wire tension controls the amount of bend in the mast. When you tension up the rig take a look from the base of the mast up to the top, right along the sail track. Adjust as necessary to get the mast straight. Now take it for a sail upwind. When the boat is heeled (spelling?) over at least 20 degrees look up the mast again. If the mast is not straight you need to adjust the relative tension between the uppers and lowers. Cable does not have a liner load versus deflection curve. In other words doubling the load in the cable does not double the stretch. If the top of the mast is hooking to windward you can either loosen BOTH uppers or tighten BOTH (all 4?) lowers. If you are tighening the lowers you move them to a stiffer portion of the load/deflection curve and the hook will disappear. It will take a few attempts to get things just right. On the cutter rigged boats the problem is even more complicated in that we have the inner forestay and baby stays to add into the mix. Racers use fore and aft bend in the mast to help flatten or give the sail draft. I do not recommend this for the novice as too much bend can reduce the masts column stability. I would shoot for a straight mast.
One down side of rigging that goes too loose on the leward side is that the cable can flop around. This can cause the bending stresses in the end fittings. On a small diameter part, small bending loads can cause more stress than the tension does on the opposite tack. Every Cape Dory that I have seen has the proper toggels at the end so that this will not cause a problem. The other drawback of loose rigging has to do with the spreaders. This varies with the model, but the upper shrouds are often only held into the spreader by the tension in the rig forcing it into a notch. If the shroud is so loose that it can pop out your rig will likely come down. Additionally if the shroud is very loose the spreader can work in a fore and aft direction. This can stress the joint at the root of the spreader. On a Pererson 46 which I sailed across the atlantic the shrouds were too loose and the holes at the root end of the spreader were badly elongated.
My overall recommendation is that if the leward wires flop around much when the rig is heavily loaded, then it is better to tighten them up a bit.
Good Luck.
Matt
ps. Using all capital letters is the e-mail equivalent to yelling.
mcawthor@bellatlantic.net
I am not sure which boat you have and the rigs vary a bit. I generally agree that the wires should not be "bar taught". The wire tension controls the amount of bend in the mast. When you tension up the rig take a look from the base of the mast up to the top, right along the sail track. Adjust as necessary to get the mast straight. Now take it for a sail upwind. When the boat is heeled (spelling?) over at least 20 degrees look up the mast again. If the mast is not straight you need to adjust the relative tension between the uppers and lowers. Cable does not have a liner load versus deflection curve. In other words doubling the load in the cable does not double the stretch. If the top of the mast is hooking to windward you can either loosen BOTH uppers or tighten BOTH (all 4?) lowers. If you are tighening the lowers you move them to a stiffer portion of the load/deflection curve and the hook will disappear. It will take a few attempts to get things just right. On the cutter rigged boats the problem is even more complicated in that we have the inner forestay and baby stays to add into the mix. Racers use fore and aft bend in the mast to help flatten or give the sail draft. I do not recommend this for the novice as too much bend can reduce the masts column stability. I would shoot for a straight mast.
One down side of rigging that goes too loose on the leward side is that the cable can flop around. This can cause the bending stresses in the end fittings. On a small diameter part, small bending loads can cause more stress than the tension does on the opposite tack. Every Cape Dory that I have seen has the proper toggels at the end so that this will not cause a problem. The other drawback of loose rigging has to do with the spreaders. This varies with the model, but the upper shrouds are often only held into the spreader by the tension in the rig forcing it into a notch. If the shroud is so loose that it can pop out your rig will likely come down. Additionally if the shroud is very loose the spreader can work in a fore and aft direction. This can stress the joint at the root of the spreader. On a Pererson 46 which I sailed across the atlantic the shrouds were too loose and the holes at the root end of the spreader were badly elongated.
My overall recommendation is that if the leward wires flop around much when the rig is heavily loaded, then it is better to tighten them up a bit.
Good Luck.
Matt
ps. Using all capital letters is the e-mail equivalent to yelling.
WILL SOMEONE PLEASE EXPLAIN THE RATIONAL FOR TIGHTENING STAYS AND SHROUDS TO THE POINT WHERE THEY "TWANG" I TIGHTEN MY TURNBUCKLES SO THAT THE STAYS AND SHROUDS ARE JUST TAUT AND YES THE SHROUDS ON THE LEEWARD SIDE DO SHOW A LITTLE SLACK IN A GOOD BREEZE BUT SO WHAT ,THE WINDWARD STAYS SNUG UP TIGHT AND KEEP THE MAST WHERE IT BELONGS. MAYBE I'M WRONG, IF SO PLEASE EXPLAIN WHY
mcawthor@bellatlantic.net