I've read how important the vang is to sail shape. Particularly to bring the top batten parallel to the boom. After working with it yesterday I fail to see much difference on a beat with the vang tight or loose. Actually I can't hardly tighten it enough to bring the top batten in parallel to the boom. I've always just kept it tight as I can get it to keep the boom down on all points of sail. Am I missing something?
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M
Mark
Use mainsheet to help
When we want to put more on with the vang we quickly bring in the boom to centre and pull on lots of mainsheet. Whilst the tension is on we pull on the vang and lock it tight, release the mainsheet and let the boom swing.
When we want to put more on with the vang we quickly bring in the boom to centre and pull on lots of mainsheet. Whilst the tension is on we pull on the vang and lock it tight, release the mainsheet and let the boom swing.
C
Cliff Ruckstuhl
Off the wind
The vang is for off the wind or down wind and does not play as much of a roll up wind. If you are on a reach with the main let out it will cause the boom to rise. The vang pulled down will stop this. Cliff
The vang is for off the wind or down wind and does not play as much of a roll up wind. If you are on a reach with the main let out it will cause the boom to rise. The vang pulled down will stop this. Cliff
Boom vang can be useful going upwind
My sail trim manual says that boom vang tension is useful when going upwind. Apparently, enough vang tension will open the leech of the mainsail and increase twist (very useful when the wind picks up). This happens because the vang not only pulls the boom down (just like a hardened mainsheet when close-hauled) but also pushes the boom (and the middle of the mast, which is connected to it at the gooseneck) forward and to windward. This is something the mainsheet cannot do. The masthead responds to vang tension by moving backward and downward, just as if the backstay had been tensioned. It also bends off slightly to leeward. This works as long as the mid-mast (the section between the foot and the forestay attachment point) is not too stiff. Mid-mast stiffness is controlled by lower shroud tension. Decreasing tension in the lowers allows the mid-mast area to bow more, so it can move forward (and sideways) as vang tension (or backstay tension) is increased. As long as the upper shrouds and the forestay are properly tensioned, the point where they all come together near the top of the mast remains practically motionless. The fractionally-rigged “bendy” Z-Spar mast on some H23s is ideal for this type of rig trim. If you notice, the only stay that goes to the top of the mast is the backstay. The upper shrouds and the forestay are all attached at the same level, about three feet below the masthead. The vang is properly tensioned for close-hauled sailing when the boom “floats”, i.e., very little mainsheet tension is needed to pull the boom inward to the proper angle of attack. This is because most of the downward pull is already being applied by the vang. The downside is that you need a very powerful vang to produce enough downward pull (at a 60 degree angle) to overcome the mainsheet, which is pulling almost straight down. This is why some performance dinghies like the 407 have a cascade system for the vang, and explains why 12:1 vang tackles and solid vangs are popular on true race boats. If you're just cruising around, it's not a big deal, but if you're trying to utilize more of your boat's perormance potential, it's worth looking into. So much for the theory, I’m still modifying my boat so I can applying it successfully out on the water, where it counts. Right now, I’m re-rigging my vang so I can control it from the cockpit. The cunningham is already done and it does make a difference. Peter H23 "Raven"
My sail trim manual says that boom vang tension is useful when going upwind. Apparently, enough vang tension will open the leech of the mainsail and increase twist (very useful when the wind picks up). This happens because the vang not only pulls the boom down (just like a hardened mainsheet when close-hauled) but also pushes the boom (and the middle of the mast, which is connected to it at the gooseneck) forward and to windward. This is something the mainsheet cannot do. The masthead responds to vang tension by moving backward and downward, just as if the backstay had been tensioned. It also bends off slightly to leeward. This works as long as the mid-mast (the section between the foot and the forestay attachment point) is not too stiff. Mid-mast stiffness is controlled by lower shroud tension. Decreasing tension in the lowers allows the mid-mast area to bow more, so it can move forward (and sideways) as vang tension (or backstay tension) is increased. As long as the upper shrouds and the forestay are properly tensioned, the point where they all come together near the top of the mast remains practically motionless. The fractionally-rigged “bendy” Z-Spar mast on some H23s is ideal for this type of rig trim. If you notice, the only stay that goes to the top of the mast is the backstay. The upper shrouds and the forestay are all attached at the same level, about three feet below the masthead. The vang is properly tensioned for close-hauled sailing when the boom “floats”, i.e., very little mainsheet tension is needed to pull the boom inward to the proper angle of attack. This is because most of the downward pull is already being applied by the vang. The downside is that you need a very powerful vang to produce enough downward pull (at a 60 degree angle) to overcome the mainsheet, which is pulling almost straight down. This is why some performance dinghies like the 407 have a cascade system for the vang, and explains why 12:1 vang tackles and solid vangs are popular on true race boats. If you're just cruising around, it's not a big deal, but if you're trying to utilize more of your boat's perormance potential, it's worth looking into. So much for the theory, I’m still modifying my boat so I can applying it successfully out on the water, where it counts. Right now, I’m re-rigging my vang so I can control it from the cockpit. The cunningham is already done and it does make a difference. Peter H23 "Raven"
J
Jim Maroldo
The vang & the top batten
I may be wrong here, Mike, but I'm getting the feeling that you're trying to bring the top batten DOWN to where it's parallel to the boom in the vertical dimension? This would be impossible since the vang is pulling the boom down which then pulls the sail. I believe the intent is to reduce the tendency for the upper part of the main to twist off to leeward. If the top batten is at the same angle of attack as the boom, you have more of the sail working, and thus greater efficiency. What ratio blocks are you using on your vang? We have a 6:1 on our H23, but I was thinking of going up to 8:1 to make it a bit easier to tighten. Enjoy! Jim Maroldo s/v: Lil' Wass Ett
I may be wrong here, Mike, but I'm getting the feeling that you're trying to bring the top batten DOWN to where it's parallel to the boom in the vertical dimension? This would be impossible since the vang is pulling the boom down which then pulls the sail. I believe the intent is to reduce the tendency for the upper part of the main to twist off to leeward. If the top batten is at the same angle of attack as the boom, you have more of the sail working, and thus greater efficiency. What ratio blocks are you using on your vang? We have a 6:1 on our H23, but I was thinking of going up to 8:1 to make it a bit easier to tighten. Enjoy! Jim Maroldo s/v: Lil' Wass Ett
M
mike
thanks
Good info guys, thanks! I'm starting to get the picture. Not sure what my vang purchase is but I should increase it. Might also loosen my lower shrouds a la Peter's input. Thanks a bunch!
Good info guys, thanks! I'm starting to get the picture. Not sure what my vang purchase is but I should increase it. Might also loosen my lower shrouds a la Peter's input. Thanks a bunch!
Vang purchase
"Purchase" is the number of times your pull on the end of the line is multiplied by the tackle. It's what they called "mechanical advantage" back in high school physics. In simple tackle systems it's the number of times the line goes back and forth between the sheaves (pulleys). More sophisticated tackles can be rigged using a cascade to obtain even hiogher purchase. The Harken catalog (free in most marine stores) is a good source of information on tackles and purchases. Good luck. Peter H23 "Raven"
"Purchase" is the number of times your pull on the end of the line is multiplied by the tackle. It's what they called "mechanical advantage" back in high school physics. In simple tackle systems it's the number of times the line goes back and forth between the sheaves (pulleys). More sophisticated tackles can be rigged using a cascade to obtain even hiogher purchase. The Harken catalog (free in most marine stores) is a good source of information on tackles and purchases. Good luck. Peter H23 "Raven"
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