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Rigid Boom Vangs
1 point each
What are the benefits of Rigid Boom Vangs? What are the various types? How do they compare with conventional Vangs/Topping Lifts? Is there a Rigid Boom Vang that eliminates the weaknesses of a rigid design? How do these compare with a "Push Down" type boom vang? |
Rigid Boom Vangs
"Bart Senior" wrote in message . net... 1 point each What are the benefits of Rigid Boom Vangs? Holds boom in a fixed vertical plane What are the various types? Hydraulic, Block and Tackle, Combinaton How do they compare with conventional Vangs/Topping Lifts? Provide bi directional adjustment in all horizontal planes Is there a Rigid Boom Vang that eliminates the weaknesses of a rigid design? Don't know but I hope it's Selden as that's what I got. How do these compare with a "Push Down" type boom vang? ???? |
What are the benefits of Rigid Boom Vangs?..
Looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" |
I'd never thought of using one. But the rigging company who is doing the
work on the boat was offered a deal from the manufacturer when they ordered the new boom. They want the rigging company to try one, the price through them was way inexpensive. . . .so . .why not? Be a new experience. M. "SAIL LOCO" wrote in message ... What are the benefits of Rigid Boom Vangs?.. Looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" |
"Bart Senior" wrote in message . net... | 1 point each | | What are the benefits of Rigid Boom Vangs? The only real benefit I can see on a cruiser would be the ability to negate the use of the topping lift on the boom. | | What are the various types? I believe there are hydraulic, compressed air and spring loaded varieties. | | How do they compare with conventional Vangs/Topping Lifts? More complicated design and thus you pay for the ease of use by possible a failure being much more difficult to repair at sea. Stiffer performance and less need for adjustments. | | Is there a Rigid Boom Vang that eliminates the weaknesses of | a rigid design? I don't know | | How do these compare with a "Push Down" type boom vang? I don't know ....and donate any points to Scotty! ;-) CM |
3 points
"Capt. Mooron" wrote "Bart Senior" wrote | 1 point each | | What are the benefits of Rigid Boom Vangs? The only real benefit I can see on a cruiser would be the ability to negate the use of the topping lift on the boom. | | What are the various types? I believe there are hydraulic, compressed air and spring loaded varieties. | | How do they compare with conventional Vangs/Topping Lifts? More complicated design and thus you pay for the ease of use by possible a failure being much more difficult to repair at sea. Stiffer performance and less need for adjustments. |
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They want the rigging company to try one, the price through
them was way inexpensive. . . .so . .why not? Be a new experience.. Raises the boom in light air, eliminates the toping lift AND looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" |
Do you have personal experience with this Oz?
OzOne wrote On 15 Aug 2004 00:29:13 GMT, (SAIL LOCO) scribbled thusly: They want the rigging company to try one, the price through them was way inexpensive. . . .so . .why not? Be a new experience.. Raises the boom in light air, eliminates the toping lift AND looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" And shatter into a thousand pieces if to broach and chinese gybe in a gale. Oz1...of the 3 twins. |
Horass, this really sounds gay... time to go back on your
meds. In article , Horvath wrote: On 14 Aug 2004 13:56:28 GMT, (SAIL LOCO) wrote this crap: What are the benefits of Rigid Boom Vangs?.. Looks cool. Carefull. Jon-boy thinks anything rigid looks cool. Pathetic Earthlings! No one can save you now! -- Jonathan Ganz (j gan z @ $ail no w.c=o=m) http://www.sailnow.com "If there's no wind, row." |
And shatter into a thousand pieces if to broach and chinese gybe in a
gale. Hasn't happened to my Quick Vang. We've done a couple of pole in the water auto jibes with the chute up with no damage. S/V Express 30 "Ringmaster" "Trains are a winter sport" |
My friend designed a boom brake and later designed a
hydraulic vang and the boom broke. Now he has a boom brake and a broke boom! What brands of rigid vangs do you like? I'm trying to decide on one, or else I'll make a big rope boom vang. OzOne wrote On Sun, 15 Aug 2004 04:00:12 GMT, "Bart Senior" scribbled thusly: Do you have personal experience with this Oz? Yep! Though it was quite a while ago. We worked out that the lack of shock absorbtion in the system was causing problems with cracking booms and eventually an exploded vang. I believe that the newer systems have overcome this. OzOne wrote On 15 Aug 2004 00:29:13 GMT, (SAIL LOCO) scribbled thusly: They want the rigging company to try one, the price through them was way inexpensive. . . .so . .why not? Be a new experience.. Raises the boom in light air, eliminates the toping lift AND looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" And shatter into a thousand pieces if to broach and chinese gybe in a gale. Oz1...of the 3 twins. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. |
We use a rope vang on the Yamaha 30. One nice advantage is
that you can release the foot and use the vang as a preventer by attaching it to the toe rail. -- "j" ganz @@ www.sailnow.com "Bart Senior" wrote in message . .. My friend designed a boom brake and later designed a hydraulic vang and the boom broke. Now he has a boom brake and a broke boom! What brands of rigid vangs do you like? I'm trying to decide on one, or else I'll make a big rope boom vang. OzOne wrote On Sun, 15 Aug 2004 04:00:12 GMT, "Bart Senior" scribbled thusly: Do you have personal experience with this Oz? Yep! Though it was quite a while ago. We worked out that the lack of shock absorbtion in the system was causing problems with cracking booms and eventually an exploded vang. I believe that the newer systems have overcome this. OzOne wrote On 15 Aug 2004 00:29:13 GMT, (SAIL LOCO) scribbled thusly: They want the rigging company to try one, the price through them was way inexpensive. . . .so . .why not? Be a new experience.. Raises the boom in light air, eliminates the toping lift AND looks cool. S/V Express 30 "Ringmaster" "Trains are a winter sport" And shatter into a thousand pieces if to broach and chinese gybe in a gale. Oz1...of the 3 twins. Oz1...of the 3 twins. I welcome you to crackerbox palace,We've been expecting you. |
"Bart Senior" wrote in message My friend designed a boom brake and later designed a hydraulic vang and the boom broke. Now he has a boom brake and a broke boom! What brands of rigid vangs do you like? I'm trying to decide on one, or else I'll make a big rope boom vang. A friend with a new Catalina 350 had what I assume was a Garhauer rigid vang. Sailing with him several weeks ago we bent the thing by overtightening the mainsheet. Apparently there was not enough compression allowance in the vang to allow the boom to drop much. So Garhauer sent him a new vang--a completely different design--with heavy machined aluminum endpieces and what appears to be a heavier hydraulic piston assembly. Has anyone seen this unit or had any experience with it? Looks good, but who knows. Max |
Heh... if they have that kind of after-market responsibility... I'd buy from
them in a New York Minute. CM "Maxprop" wrote in message | A friend with a new Catalina 350 had what I assume was a Garhauer rigid | vang. Sailing with him several weeks ago we bent the thing by | overtightening the mainsheet. Apparently there was not enough compression | allowance in the vang to allow the boom to drop much. So Garhauer sent him | a new vang--a completely different design--with heavy machined aluminum | endpieces and what appears to be a heavier hydraulic piston assembly. Has | anyone seen this unit or had any experience with it? Looks good, but who | knows. | | Max | | |
I've looked at the Garhauer vangs. I like them.
They make great equipment that will outlast all of us. I'm not sure of Garhauer can make one for my boat. My main is 440 sq ft. And that could grow if I eventually get a new main with more roach. Their biggest may not be big enough. I'd have to call and check on that. I'm not convinced I'd want one of their boom vangs. The sheeting seems bulky compared with other brands. My running backs do not interfere with my boom, so if I can get rid of the topping lift, an unintentional tack would only chafe the sail. That frees my topping lift halyard for a Dutchman flaking system--not that it would not be hard to add another halyard. So this is why I'm thinking about rigid vangs. "Maxprop" wrote A friend with a new Catalina 350 had what I assume was a Garhauer rigid vang. Sailing with him several weeks ago we bent the thing by overtightening the mainsheet. Apparently there was not enough compression allowance in the vang to allow the boom to drop much. So Garhauer sent him a new vang--a completely different design--with heavy machined aluminum endpieces and what appears to be a heavier hydraulic piston assembly. Has anyone seen this unit or had any experience with it? Looks good, but who knows. Max |
My boat, 17' boom, 510 sf main, came with a Forespar solid vang. If I
was ever to replace it, Garhauer would be my choice. They make one that fits my boat, and by extension, yours. On Tue, 17 Aug 2004 05:09:40 GMT, "Bart Senior" wrote: I've looked at the Garhauer vangs. I like them. They make great equipment that will outlast all of us. I'm not sure of Garhauer can make one for my boat. My main is 440 sq ft. And that could grow if I eventually get a new main with more roach. Their biggest may not be big enough. I'd have to call and check on that. I'm not convinced I'd want one of their boom vangs. The sheeting seems bulky compared with other brands. My running backs do not interfere with my boom, so if I can get rid of the topping lift, an unintentional tack would only chafe the sail. That frees my topping lift halyard for a Dutchman flaking system--not that it would not be hard to add another halyard. So this is why I'm thinking about rigid vangs. "Maxprop" wrote A friend with a new Catalina 350 had what I assume was a Garhauer rigid vang. Sailing with him several weeks ago we bent the thing by overtightening the mainsheet. Apparently there was not enough compression allowance in the vang to allow the boom to drop much. So Garhauer sent him a new vang--a completely different design--with heavy machined aluminum endpieces and what appears to be a heavier hydraulic piston assembly. Has anyone seen this unit or had any experience with it? Looks good, but who knows. Max |
Bart,
I know that topping lift can be a PITA but it still has a lot of advantages over the rigid vang. Just to mention a few; A spare and ready back stay A man overboard hoist An end reinforcement of the boom when you want to use it as a crane (Dingy recovery) Ole Thom P/S I've used to tail as a temporary sheet while clearing an over-ride on the main sheet wench |
In fact the rigging shop said they weren't taking off the topping lift and
for all the reasons Thom mentioned. M. "Thom Stewart" wrote in message ... Bart, I know that topping lift can be a PITA but it still has a lot of advantages over the rigid vang. Just to mention a few; A spare and ready back stay A man overboard hoist An end reinforcement of the boom when you want to use it as a crane (Dingy recovery) Ole Thom P/S I've used to tail as a temporary sheet while clearing an over-ride on the main sheet wench |
Michael wrote:
In fact the rigging shop said they weren't taking off the topping lift and for all the reasons Thom mentioned. The only thing Ol' Thom listed that a rigid vang can't do is become an emergency backstay. It will (or should) be able to support the boom for hoisting. DSK |
"DSK" wrote in message The only thing Ol' Thom listed that a rigid vang can't do is become an | emergency backstay. It will (or should) be able to support the boom for | hoisting. Not a chance Doug! The mechanics are all wrong and the placement is useless for that purpose. CM |
The only way I could even contemplate that would be to disconnect it
from the base of the mast, then put it somewhere back, but I can't imagine it would do much good. In article , Capt. Mooron wrote: "DSK" wrote in message The only thing Ol' Thom listed that a rigid vang can't do is become an | emergency backstay. It will (or should) be able to support the boom for | hoisting. Not a chance Doug! The mechanics are all wrong and the placement is useless for that purpose. CM -- Jonathan Ganz (j gan z @ $ail no w.c=o=m) http://www.sailnow.com "If there's no wind, row." |
DSK,
If you use the solid vange to hold up the boom when using it for a crane, it will soon be like Neals Boom, with a pipe in it. The topping lift bears the load. The boom only position the lifting location. Ole Thom |
Capt. Mooron wrote:
Not a chance Doug! The mechanics are all wrong and the placement is useless for that purpose. ??? It holds up the boom, right? Jonathan Ganz wrote: The only way I could even contemplate that would be to disconnect it from the base of the mast, then put it somewhere back, but I can't imagine it would do much good. ??? ??? Have either of you all ever actually seen a solid vang? DSK |
Thom Stewart wrote:
If you use the solid vange to hold up the boom when using it for a crane, it will soon be like Neals Boom, with a pipe in it. The topping lift bears the load. The boom only position the lifting location. Not if it was built properly in the first place. I must be more spoiled than I realize, having sailed boats with strong spars and decent rigging. Oh well. If your boom will not lift a dinghy then it will not stand up to hard sailing either. A topping lift might "bear the load" but it also puts the boom under more compression than the weight of the load. The usual failure point (in my experience) is the gooseneck. Fresh Breezes- Doug King |
Yup.... and no way it would hold the boom so I could hoist the auxiliary out
of the engine room with one! For that you need a topping lift.. CM "DSK" wrote in message | Have either of you all ever actually seen a solid vang? | | DSK | |
Capt. Mooron wrote:
Yup.... and no way it would hold the boom so I could hoist the auxiliary out of the engine room with one! For that you need a topping lift.. In that case, the solid vangs you've seen (and/or the booms) were sadly lacking. If it won't hold up a piddly little outboard motor, how is it going to hold the force of the whole boat driving the boom tip into wave crests, or any of the other things that can be expected to happen when you *really* sail, occasionally in hard conditions? I think you're forming your opinion based on incomplete data. A *real* solid vang (and boom) will fulfill all the functions of a topping lift, except as an emergency backstay replacement. I've seen a lot that wouldn't, but I don't like them either. It's sort of like a centerboard one-design that won't plane... what's the point? Fresh Breezes- Doug King |
In article ,
DSK wrote: A *real* solid vang (and boom) will fulfill all the functions of a topping lift, except as an emergency backstay replacement. I've seen a lot that wouldn't, but I don't like them either. It's sort of like a centerboard one-design that won't plane... what's the point? Doug, I thougth that's what you were saying it would do... as an emergency backstay. Oh well... my reading comprehension is going downhill fast. -- Jonathan Ganz (j gan z @ $ail no w.c=o=m) http://www.sailnow.com "If there's no wind, row." |
Jonathan Ganz wrote:
Doug, I thougth that's what you were saying it would do... as an emergency backstay. Oh well... my reading comprehension is going downhill fast. My bad. I have been in a hurry all week and am probably not writing very clearly. DSK |
"DSK" wrote in message | If it won't hold up a piddly little outboard motor, how is it going to | hold the force of the whole boat driving the boom tip into wave crests, | or any of the other things that can be expected to happen when you | *really* sail, occasionally in hard conditions? it's an auxiliary diesel.. 30 HP! The vang holds the boom down not up... yes it has the capacity to hold up a boom up with some weight.... but that is not it's primary function. Leverage is required at the end of the boom for lifting. I'm certain you are familiar with fulcrums? Where would you fasten the mainsheet to the boom... generally it's 50% of the length or more. Look where the vang is... at what 15%? | | I think you're forming your opinion based on incomplete data. My data seems more complete than yours at the moment Doug. | | A *real* solid vang (and boom) will fulfill all the functions of a | topping lift, except as an emergency backstay replacement. I've seen a | lot that wouldn't, but I don't like them either. No Way Doug!! No for all the tea in China. The engineering is out to lunch for such a claim. CM |
Capt. Mooron wrote:
it's an auxiliary diesel.. 30 HP! ??? What is? .... The vang holds the boom down not up... Therein lies your error. A solid vang holds the boom up and down. yes it has the capacity to hold up a boom up with some weight.... but that is not it's primary function. Why isn't it? That's like saying that because a bridge is designed for cars to drive over it, it won't hold up a person walking across. Leverage is required at the end of the boom for lifting. I'm certain you are familiar with fulcrums? Yes. I fail to see your point though. If the vang holds the boom up, then it holds the boom up. If the vang will hold the boom down under heavy sailing loads, then it will probably hold at least as much in the opposite direction, nyet? How much leach tension do you think your boat generates in a good breeze? Where would you fasten the mainsheet to the boom... generally it's 50% of the length or more. Look where the vang is... at what 15%? Depends. It's not a relevant issue though. Wherever the boom vang is attached, if it will stand up to the load then it will... umm... stand up to the load. If not, then it wasn't strong enough to begin with and that's true whether it's a solid vang or not. | | A *real* solid vang (and boom) will fulfill all the functions of a | topping lift, except as an emergency backstay replacement. I've seen a | lot that wouldn't, but I don't like them either. No Way Doug!! No for all the tea in China. The engineering is out to lunch for such a claim. Actually the engineering is quite sound. If you have problems with vangs breaking and booms folding up, then that suggests that your engineering needs a little more beef and less cheese. Fresh Breezes- Doug King |
Doug,
Think about the mechanics of both your statement and mine By using the topping lift for Hoisting the total strength of the Rig is used (Shrouds, fore and back stays; In my case double lower shrouds to keep Mast in line. With the Rigid Vang in Hoisting, you are putting Max Effort on the end of the boom, supported at a point about 1/4 of the way back from the Gooseneck. That is an awful long unsupported Alum. Pole. (Hollow Aluminium Pole). In operation, the force of the sail is at least two points on the boom, with the main sheet countering the force on the boom. Often assisted by the Vang. Often over assisted by a Hydra. Rigid Vang. I'm sure, as an Engineer, you can admit to the difference If you were careening the hull, you wouldn't weight the end of the boom without the back-up of the topping lift and/or a halyard to call on the full strength of the total rig. The topping lift is a solid connection. The halyard is a varying force Just some things to remind you of. I'm not knocking the Rigid Vang. I wish I could fit one on my boat but the Pilothouse makes that impossible. I'm thinking I might be able to use a KICKER. I'm pointing out that PITA top lift still is a worthwhile addition. Ole Thom |
Thom Stewart wrote:
Doug, Think about the mechanics of both your statement and mine OK By using the topping lift for Hoisting the total strength of the Rig is used (Shrouds, fore and back stays; In my case double lower shrouds to keep Mast in line. OK With the Rigid Vang in Hoisting, you are putting Max Effort on the end of the boom, supported at a point about 1/4 of the way back from the Gooseneck. That is an awful long unsupported Alum. Pole. (Hollow Aluminium Pole). OK Oh, are you saying that the boom might fold up? You're right, but it shouldn't unless it was too weak to start with. Is your boom the same spar section as your mast? If so then it probably isn't strong enough to use with a solid vang anyway. Think about this, Thom... the force on the end of the boom is going to be very great when sailing hard... enough to lean the boat over a lot. If the boom end can take that force, then it should take that same force in the form of a weight heavy enough to heel the boat over. In operation, the force of the sail is at least two points on the boom, with the main sheet countering the force on the boom. Often assisted by the Vang. Often over assisted by a Hydra. Rigid Vang. I'm sure, as an Engineer, you can admit to the difference Yep. The difference is that in one case, you have put the boom & mast under compression by tensioning the whole rig. In the other, you have put the boom under a torsion load, and on a much smaller part of the mast, and none on the rig (which actually means less stress on the hull). If you were careening the hull, you wouldn't weight the end of the boom without the back-up of the topping lift and/or a halyard to call on the full strength of the total rig. Probably not to careen the boat, but if I had a solid vang suitable for hard sailing, I would not hesitate to hoist a weight on the boom that would heel the boat far enough to put the boom in the water. ... The topping lift is a solid connection. ??? The halyard is a varying force ??? Just some things to remind you of. I'm not knocking the Rigid Vang. I wish I could fit one on my boat but the Pilothouse makes that impossible. I'm thinking I might be able to use a KICKER. I'm pointing out that PITA top lift still is a worthwhile addition. In some cases, yes very much. In others, it's just in the way. My point is that if a boat & it's rig is engineered to take proper advantage of a solid vang, then you do not need a topping lift. Do not. Period. If the rig is noodley and engineered to transfer compressive loads through a series of components, then a solid vang can be added for convenience but it will not be as useful. If the rig has a very low boom or a pilothouse, there's not room for a proper vang anyway... but you can probably do a lot of the same sail trim functions with a wide traveler. Fresh Breezes- Doug King |
Doug,
Your Bridge example is WRONG. Those cables hanging down are for suspension. Not compression. I think you can remember the Tacoma Narrows Bridge when the wind got under it. IT FALL DOWN GO KAPLUNK! OT |
Since you're clearly not perfect, I'm going to change my
vote for president... to Willie Nelson. In article , DSK wrote: Jonathan Ganz wrote: Doug, I thougth that's what you were saying it would do... as an emergency backstay. Oh well... my reading comprehension is going downhill fast. My bad. I have been in a hurry all week and am probably not writing very clearly. -- Jonathan Ganz (j gan z @ $ail no w.c=o=m) http://www.sailnow.com "If there's no wind, row." |
"DSK" wrote in message | Yes. I fail to see your point though. If the vang holds the boom up, | then it holds the boom up. | | If the vang will hold the boom down under heavy sailing loads, then it | will probably hold at least as much in the opposite direction, nyet? No Doug! No No No!.... look the vang may be able to hold the stresses on a sail "down"... but it will never hold the stresses of a weight at the end of the boom "UP". The leverage just isn't there. This is not a hydraulic arm on an excavator! If it were the vang would be massive ... require an engine to power the compressor and be attached to the end of the boom. Look..... I can understand where your assumptions are based but I'm thinking you have not taken into consideration the engineering incorporated into the vang and it's intended use. If you have 10,000 lbs of pressure on the main only a fraction of that force will be utilized to incur lift on the boom. The vang is not holding down the entire pressure placed on the main. For using the boom as a lifting device.... you will stress the vang unduly with a set-up located that far back on the load arm. It's not designed for that. A topping lift to the end of the boom requires much less force to hold the boom level on a lift than the stresses placed on a vang that is located at 15% of the load arm length. I don't care if it's a 1/2" I Channel carbon steel beam for a boom! We are not discussing boom failure here.... we are discussing load bearing to the vang. I await your rebuttal... :-) CM |
Thom I can't support your example here because you are bringing in an
ancillary factor of boom strength. That is not the subject... the subject is the suitability and ability of a rigid vang to support the loads generated at the end of the boom in a lift situation. I concur with your assessment that the vang is not up to the task or poorly positioned and designed to accomodate such loads... but let's not bring the boom strenght into the equation. CM "Thom Stewart" wrote in message ... | Doug, | | Think about the mechanics of both your statement and mine | | By using the topping lift for Hoisting the total strength of the Rig is | used (Shrouds, fore and back stays; In my case double lower shrouds to | keep Mast in line. | With the Rigid Vang in Hoisting, you are putting Max Effort on the end | of the boom, supported at a point about 1/4 of the way back from the | Gooseneck. | That is an awful long unsupported Alum. Pole. (Hollow Aluminium Pole). | | In operation, the force of the sail is at least two points on the boom, | with the main sheet countering the force on the boom. Often assisted by | the Vang. Often over assisted by a Hydra. Rigid Vang. | | I'm sure, as an Engineer, you can admit to the difference | | If you were careening the hull, you wouldn't weight the end of the boom | without the back-up of the topping lift and/or a halyard to call on the | full strength of the total rig. The topping lift is a solid connection. | The halyard is a varying force | | Just some things to remind you of. | | I'm not knocking the Rigid Vang. I wish I could fit one on my boat but | the Pilothouse makes that impossible. I'm thinking I might be able to | use a KICKER. I'm pointing out that PITA top lift still is a worthwhile | addition. | | Ole Thom | |
| If the vang will hold the boom down under heavy sailing loads, then it
| will probably hold at least as much in the opposite direction, nyet? Capt. Mooron wrote: No Doug! No No No!.... look the vang may be able to hold the stresses on a sail "down"... but it will never hold the stresses of a weight at the end of the boom "UP". Why not? If the boom can take the torsion in one direction, then unless it is a very weird asymmetric structure, then it will take the same in the opposite direction. ... The leverage just isn't there. Sure it is. It's exactly the same in both directions. What I'm saying is the same as saying if you can stand on a beam (let's say a 2x6) between two sawhorses, and it doesn't break, then you can turn the beam over and still stand on it. You're saying that it doesn't work that way, if the beam doesn't break one way then it will definitely break the other... .... This is not a hydraulic arm on an excavator! If it were the vang would be massive ... require an engine to power the compressor and be attached to the end of the boom. The max forces are limited by the righting moment of the boat. On a 30 footer, it doesn't need to be that massive. On bigger boats... take a look at the vangs on IACC racers... Look..... I can understand where your assumptions are based but I'm thinking you have not taken into consideration the engineering incorporated into the vang and it's intended use. Actually, I have. It's not that complicated. Try drawing out a diagram of moments. If you need a refresher http://www2.umist.ac.uk/construction...xp/sfbmdex.htm ... If you have 10,000 lbs of pressure on the main only a fraction of that force will be utilized to incur lift on the boom. The vang is not holding down the entire pressure placed on the main. No, it isn't... but it is holding down 100% of the leach tension, which is very large. It also takes all the load of the mainsheet when hauled in tight to go to windward. If it doesn't break when you honk down on an 8:1 purchase, then it should hold at least 8X your honking strength ;) For using the boom as a lifting device.... you will stress the vang unduly with a set-up located that far back on the load arm. ??? ... It's not designed for that. It should be. Anything less would not be safe for sailing IMHO. I await your rebuttal... :-) If I give you a re-buttal, then who was the butt in the first place? Seriously, I'm not saying 'all solid vangs are great for lifting heavy objects' because many aren't. But then remember Sturgeons Law '90% of everything is crap' and then tell me why it *shouldn't* be. Some are. I know that for a fact. And if I had a solid vang that's what I'd insist on. YMMV DSK |
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"DSK" wrote in message | Why not? If the boom can take the torsion in one direction, then unless | it is a very weird asymmetric structure, then it will take the same in | the opposite direction. This is where you stray from engineering principal... that is not the case at all nor is it the rule. | Sure it is. It's exactly the same in both directions. No Doug... it is most assuredly not the same in both directions if only by the points of compression | | What I'm saying is the same as saying if you can stand on a beam (let's | say a 2x6) between two sawhorses, and it doesn't break, then you can | turn the beam over and still stand on it. You're saying that it doesn't | work that way, if the beam doesn't break one way then it will definitely | break the other... That's not at all what I said and again you are attempting to introduce the boom as a factor... that is not good methodology for what we are discussing here.... forget the boom or assume it indestrutructable and unbendable.| | The max forces are limited by the righting moment of the boat. On a 30 | footer, it doesn't need to be that massive. On bigger boats... take a | look at the vangs on IACC racers... Nobody is discussing righting moment here Doug... we are discussing the ability of basic mathematics in regards to the placement of the vang and the loads you expect it to encounter. | Actually, I have. It's not that complicated. Try drawing out a diagram | of moments. If you need a refresher | http://www2.umist.ac.uk/construction...xp/sfbmdex.htm | No Doug... it's not that I refuse to seek knowledge but this time you had better be able to logically explain your theory to me without a jaxxian reflex to google proof that may or may not have bearing on what we are discussing. | No, it isn't... but it is holding down 100% of the leach tension, which | is very large. It also takes all the load of the mainsheet when hauled | in tight to go to windward. If it doesn't break when you honk down on an | 8:1 purchase, then it should hold at least 8X your honking strength ;) No Doug... it is most certainly NOT holding down 100% of the leech tension... that load is divided with a bigger factor attributed to the mainsheet. | | | For using the boom as a lifting device.... you will stress the vang unduly | with a set-up located that far back on the load arm. | | ??? Well come on now Doug.... it's basic common sense engineering principal! | ... It's not designed for | that. | | It should be. Anything less would not be safe for sailing IMHO. No it's not... it's designed as a VANG! CM |
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