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-   -   Is a Vang Really Useful on a mid to Large Boat? (http://www.sailnet.com/forums/gear-maintenance/119809-vang-really-useful-mid-large-boat.html)

Sabreman 01-29-2014 10:11 PM

Is a Vang Really Useful on a mid to Large Boat?
 
I have a vang that I hate and consider virtually worthless. I'm considering removing it and am looking for opinions. I get that on a smaller boat, the vang is very useful to shape the main as the wind increases. But on the configuration shown below with the mid-boom sheeting, I wonder if it is of any use. Upwind, no matter how much tension I put on it (as shown: 4:1, now rigged as 8:1), there is no change. I can get some purchase, but it's minimal - maybe an inch or 2 on an 8:1 rig. The angles are horrendous and I see no realistic way to improve them. So why bother at all? Off the wind, I use a preventer attached to an eye on the outboard genoa track which is very effective at bringing the boom down.

Should I ditch the vang and stay with the preventer? This discussion is not about rigid vangs, it's about whether any vang can effectively shape a mid-size main with mid-boom sheeting.


http://i99.photobucket.com/albums/l3...up2012Stbd.jpg

Classic30 01-29-2014 10:21 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
Quote:

Originally Posted by Sabreman (Post 1358737)
I have a vang that I hate and consider virtually worthless. I'm considering removing it and am looking for opinions. I get that on a smaller boat, the vang is very useful to shape the main as the wind increases. But on the configuration shown below with the mid-boom sheeting, I wonder if it is of any use. Upwind, no matter how much tension I put on it (as shown: 4:1, now rigged as 8:1), there is no change. I can get some purchase, but it's minimal - maybe an inch or 2 on an 8:1 rig. The angles are horrendous and I see no realistic way to improve them. So why bother at all? Off the wind, I use a preventer attached to an eye on the outboard genoa track which is very effective at bringing the boom down.

Should I ditch the vang and stay with the preventer? This discussion is not about rigid vangs, it's about whether any vang can effectively shape a mid-size main with mid-boom sheeting.

With the setup you have, it does seem as though the vang fixing point on the boom is a long way aft...

Within the range of your traveller, a vang will do nothing for your sail shape. If you're happy with rigging a preventer every time you're off the wind, by all means get rid of the vang.

(Personal note: I don't currently have a vang - my boat has never had one - and although I'd like one, I find either (a) a preventer rigged like you mention for long periods or (b) a spare crewmember for short periods works well enough. )

Nice boat, BTW :)

ericb760 01-29-2014 10:25 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
This post is an unpleasant reminder of how much I need to learn about sailing. Your post read like the teacher in The Peanuts sounds...

Faster 01-29-2014 10:38 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
IMO the vang is a crucial safety item when sailing downwind. It prevents the chance of an accidental goose-wing gybe. It's a pretty important trimming tool any time the boom is outside the traveler range. Even before then it can play an important role in leech tension.

If you find it an ineffective tool it probably isn't powerful enough.

I wouldn't sail without one, even if it was nothing more than a fixed strop which would be better than no vang.

Barquito 01-29-2014 10:45 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
I think that vang is set up correctly. It is about as far out on the boom as it is down from the gooseneck. Agree with others that if you don't want to set up a preventer, then the boom vang will keep the boom from riding up (it won't prevent the boom from gybing). Since I don't even have a traveler, the vang will be useful, even when close to the wind in keeping sail shape consistent as I sheet out in puffs.

Classic30 01-29-2014 10:55 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
Quote:

Originally Posted by Barquito (Post 1358873)
I think that vang is set up correctly. It is about as far out on the boom as it is down from the gooseneck. Agree with others that if you don't want to set up a preventer, then the boom vang will keep the boom from riding up....

That's what the spare crew is for. :)

Quote:

Originally Posted by Barquito (Post 1358873)
Since I don't even have a traveler, the vang will be useful, even when close to the wind in keeping sail shape consistent as I sheet out in puffs.

If you don't have a traveller, then you need a vang. The OP has a traveller (a shortish one, but a traveller nonetheless).

christian.hess 01-29-2014 10:55 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
I find preventers more useful especially on broad reaches and ddw...vangs not on every boat

long booms for example dont really need vangs but thats just my feeling and experience...

especially on old wooden boats...

now for dinchy sailing and small boat racing hell yeah

pull that vang down hard, get some bend in the boom and rake that b.................

jajaja

christian.hess 01-29-2014 11:04 PM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
Quote:

Originally Posted by Faster (Post 1358833)
IMO the vang is a crucial safety item when sailing downwind. It prevents the chance of an accidental goose-wing gybe. It's a pretty important trimming tool any time the boom is outside the traveler range. Even before then it can play an important role in leech tension.

If you find it an ineffective tool it probably isn't powerful enough.

I wouldn't sail without one, even if it was nothing more than a fixed strop which would be better than no vang.

for the newb sailor(no offence to anyone here) over reliance on vangs on downwind courses is the number one cause of boom failure, gooseneck failure and anything related to boom BREAKAGE

this is also true for improperly pullied mid boom traveller systems

this is why travellers(mainsheet) at the end of booms have such great records of non failure

for example my last boat had a rotating 4 point attachment boom end that in case of an accidental gybe what fails is the attachment point...and yes you lose the boom to the stays but you can quickly reatach mainsheet and have a nice sail...

booms that break in half are mostly caused when improper tension is exerted at a point too midway of the boom length...thats why you see massive pulley traveler systems on coachroof mainsheet traveller systems its needed...kind of like chosing your poison

My current boat is setup this way...but its a short IOR boom..so the forces involved are to an extent less than a boat with a big long boom and midpoiunt attachment

anywhoo

verbal diarhea out:D

Sabreman 01-30-2014 12:07 AM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
Thanks for the sanity check guys. The other reason that I'm considering getting rid of the vang is that I'm upgrading the traveler with a Garhauser unit. The original doesn't move as freely as it should (even after rebuilding the bearings in the car). And even with the traveler blocks at 4:1 it's still hard to move to windward in 20kts upwind - and the traveler is how we predominately trim the main. My mainsheet trimmer will love me….

So while I'm upgrading the traveler, I want to upgrade the mainsheet blocks. As it is now, the vang interferes with the mainsheet block on the boom. I've tried double blocks, and two singles but they clang and don't let the mainsheet travel as smoothly as I'd like. So if I don't need the vang, I'll get rid of it…..it's not like I can't put it back.

FYI - I upgraded the stock 4:1 to 8:1 by hooking the 4:1 to a line that passes through a single block on the boom. So 2:1 gets doubled to 8:1. Pretty cool and simple.

Quote:

It prevents the chance of an accidental goose-wing gybe.
I agree, that's why I hesitate and am questioning my logic.

RichH 01-30-2014 12:08 AM

Re: Is a Vang Really Useful on a mid to Large Boat?
 
From your pic, I might agree with Classic 30.
As I see several issues with your vang set up. (could be the angles of the pic, too)

1. the vang's connection to mast is higher than the absolute base of the mast. Looks like the geometry was chosen so that the present vang would clear an opened hatch. Getting the mast connection lower down will greatly help the vang generate more 'down' force on the boom.
Rx - do a trial with the vang pinned to the very bottom of the mast AT the coachroof. You can 'tie' a stout line around the mast base with a 'loop' (alpine butterfly knot, etc.) as the trial attachment point (w/ hatch closed).

2. From the pic, and I may be wrong, but I see a 5:1 vang being used @ 4:1 in the 'up' direction and 5:1 along the 'horizontal' direction, ..... the 'tail' of the vang seems to be running along parallel to the mast; and if so, the 'tail' is generating NO 'down' force !!!!!?????
Rx - even the vang control line should be run directly to the very 'base' of the mast.

3. Do a trial with the vang attached to the boom via 'strops/lashings' and with the 'strop connection' closer to the mast. A vang that makes a 45 angle with its boom will generate 40% more 'downforce' than a vang that makes a 30 angle intercept. (Of course when the attachment point on the boom comes closer to the mast, the 'moment force' becomes greater - a tradeoff, but should be investigated.) Your boom connection 'seems' to be a bit far aft on the boom.

Other - I often 'vang sheet' my boats (one has a Garhauer 'rigid' vang) when racing or just messing about. I initially pre-set the vang so that the boom meets the mast at a 90 angle (87 to be exact, as I have such marked on the vang control line). I can 'ease' the vang at will and under all wind strengths; but if the sail has a lot of developed wind pressure I can hardly ever be able to pull 'down' on the boom with a vang (10:1). To pull down with the vang (in above 'light-moderate' conditions), I always have to momentarily 'unload' the mainsail, reset the vang to the 'mark', then 'load up' again (takes few seconds). I dont know of many vang systems that will allow a fully loaded and drawing mainsail to be 'tightened' when the sail is 'loaded and drawing' (except when beating and the mainsheet is being over-tensioned, on purpose).
Usually most vangs require the mainsail to be 'unloaded' a bit before 'pulling in' on the vang.

;-)


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