# Rigid Boom Vang



## weephee (Oct 25, 2008)

I have a 27 foot Columbia and I am looking to purchase a rigid boom vang. I found a used one a my local chandlery for less than half the price of a new one. The distance from bottom of boom to base of mast is 33 inches. The vang compressed is approx 45 inches so the angle is somewhat less than 45 degrees. Question is, will this work or should I pass. Thanks


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## Faster (Sep 13, 2005)

That should be fine.... for 45 deg you'd need 1.414 x 33 = ~46.5 inches.. so your angle won't be that far off.

Make sure you mount it on the boom with enough clearance to fully sheet in/vang the sail for proper leech tension (ie so you won't bottom out the vang when you need it most)


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## MarkSF (Feb 21, 2011)

What I did (following the Garhauer instructions) was compress the boomvang fully, then sheet the main in hard while sailing close hauled. Then I marked the mounting points with black marker. Back to the dock and drill the holes.

They tell you to mount the vang as close to the mast base as possible. What you need to check for is that the vang will lift the boom - it might not if the angle is much less than 45 degrees. If that is the case, I suggest simply making the angle 45 degrees by having the base of the vang slightly higher.

I used 1/4" s/s rivets, for which you will need one of these :

Amazon.com: Astro Pneumatic 1426 1/4-Inch Heavy-Duty Hand Riveter: Home Improvement

Some people recommend drilling and tapping, I prefer rivets especially for the boom which is thin so a tapped thread will be weak.


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## weephee (Oct 25, 2008)

Thanks for the replies. I have just one other question. Something I don't understand is do boats with a rigid boom vang have a fiddle block with a cam at the bottom of the vang or do they make use of a cleat or spinlock aft of the mast (near the cockpit). If the latter is true then isn't there binding or restriction of some sort at the block at the bottom of the vang when the boom swings out to the port or starboard side. Thanks
Larry


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## MarkSF (Feb 21, 2011)

weephee said:


> Thanks for the replies. I have just one other question. Something I don't understand is do boats with a rigid boom vang have a fiddle block with a cam at the bottom of the vang or do they make use of a cleat or spinlock aft of the mast (near the cockpit). If the latter is true then isn't there binding or restriction of some sort at the block at the bottom of the vang when the boom swings out to the port or starboard side. Thanks
> Larry


Normally they'd bring the control line back to the cockpit as it's handier. I plan to, but haven't yet. I replaced the single block at the base of the vang with a fiddle cam cleat block, temporarily.

The block on mine is attached to a tang that swivels independently of the vang, presumably to avoid the binding you mention.


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## casey1999 (Oct 18, 2010)

I am also considering adding a rigid boom vang primarily to make reefing easier. Do the rigid vangs increase the chance of breaking your boom at the connection of the rigid boom vang, or breaking your gooseneck. The forces of the rigid vang are much different than those of a topping lift.
Regards


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## Faster (Sep 13, 2005)

casey1999 said:


> I am also considering adding a rigid boom vang primarily to make reefing easier. Do the rigid vangs increase the chance of breaking your boom at the connection of the rigid boom vang, or breaking your gooseneck. The forces of the rigid vang are much different than those of a topping lift.
> Regards


I don't think those concerns are, in fact, concerns. The support function is a 'push up' rather than a 'hold up' of a topping lift, no real difference otherwise.

Depending on what sort of rigid vang you choose, you need to be sure the support function is off (if it's selectable as some are) before tensioning the sheet.(ie make sure it's in 'VANG' mode) Most spring or gas cylinder supported styles won't have this issue.


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## jackdale (Dec 1, 2008)

casey1999 said:


> Do the rigid vangs increase the chance of breaking your boom at the connection of the rigid boom vang, or breaking your gooseneck.
> Regards


The weak point will be the vang, rather than the gooseneck or boom. I know.


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## casey1999 (Oct 18, 2010)

Faster said:


> I don't think those concerns are, in fact, concerns. The support function is a 'push up' rather than a 'hold up' of a topping lift, no real difference otherwise.
> 
> Depending on what sort of rigid vang you choose, you need to be sure the support function is off (if it's selectable as some are) before tensioning the sheet.(ie make sure it's in 'VANG' mode) Most spring or gas cylinder supported styles won't have this issue.


Yea but a rigid boom vang is operating differently from the topping lift. Topping lift produces a near vertical lift on the end of the boom. A rigid boom vang produces a vector force in the middle of the boom. Say you need 100 bls to lift the end of your boom (using topping lift). A rigid boom vang (at 30 degrees from horozontal) could be required to produce 200 lbs of vertical in the middle of the boom to give the same lift. At the same time the rigid vang would be pushing the boom out (force would be pulling the goose-neck) with a force of 346 lbs. The vang itself would have a spring (or gas) compression force of 400 lbs. On top of all this, the boom is being held in the middle instead of the end. Therefore from middle to the boom end it is a cantiler force- totally different than forces a topping lift would put on the boom.


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## Faster (Sep 13, 2005)

Yes.. I see what you were getting at.. sorry.

Still, unless you have a very thin sectioned boom ultimately there should be no issue.. looking at the other side of it (the vanging side) arguably larger loads downward are generated upon the boom section when aggressively vanging in a stiff breeze.. if the boom can take that it can likely take the 'support' forces too. And those vanging forces are present whether the vang is rigid or not.


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## MarkSF (Feb 21, 2011)

I think the raising force of the spring is very small compared to the upward loads on the mainsheet and boomvang when in a beam reach. Then you could argue that the vang is reducing the bending moment on the boom, at least with end boom sheeting, as the boom is now being pulled down at the end and at the middle.

When I apply some vang on a beam reach you can see the load on the main sheet fall.


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## casey1999 (Oct 18, 2010)

MarkSF said:


> I think the raising force of the spring is very small compared to the upward loads on the mainsheet and boomvang when in a beam reach. Then you could argue that the vang is reducing the bending moment on the boom, at least with end boom sheeting, as the boom is now being pulled down at the end and at the middle.
> 
> When I apply some vang on a beam reach you can see the load on the main sheet fall.


Maybe the only thing to be concerned about it the forces on the goose neck. Seems with a rigid boom vang (one the eliminates your topping lift) there is now a large outward force on the goose neck. A force the goose neck would normally not see. This force would not exceed the spring, gas, or hydraulic force of the rigid boom vang. As long as the goose neck is in good condition, maybe the forces should not be a problem. But then again this goose neck is not really designed for outward forces (think mine is held by rivets), so I guess it is somthing to consider and keep an eye on.

Just seems with a rigid boom vang there are forces there, but they are not apparent, like they would be if you used a topping lift and standard block and tackle vang (you know what the forces are when you pull the lines).
Regards


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## Faster (Sep 13, 2005)

I guess the lesson here is if you switch to a rigid vang, don't let those 3 drunken deck apes get into chin-up competitions on the end of the boom in the cockpit.. - at least not all at once...


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## MarkSF (Feb 21, 2011)

Yes I try to remember that the vang line has an 8:1 purchase so I try not to pull on it too hard  Strictly no putting it around a winch!


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## jgeissinger (Feb 25, 2002)

Something you should be aware of, which I learned when I had a rigid vang, is that the vang does indeed hold the boom up when attempting to reef. What it doesn't do is stop it from swinging side to side, which it will do when you release halyard tension in order to reef. It also doesn't steady the boom as well as a topping lift when docked or moored. There are pluses and minuses. I decided not to have one on my present boat.


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## casey1999 (Oct 18, 2010)

jgeissinger said:


> Something you should be aware of, which I learned when I had a rigid vang, is that the vang does indeed hold the boom up when attempting to reef. What it doesn't do is stop it from swinging side to side, which it will do when you release halyard tension in order to reef. It also doesn't steady the boom as well as a topping lift when docked or moored. There pluses and minuses. I decided not to have one on my present boat.


Yes, I saw a similar comment in another post. Another poster said he nearly fell overboard when grabbing the boom to steady himself while reefing in rough weather. I have also seen recomendations my manufacurers to use the topping lift while at dock to take the force off the rigid vang's compression spring.

Say you are reefing (and have a rigid vang) and push down on the boom, will the boom drop any?


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## jackdale (Dec 1, 2008)

jgeissinger;863292There pluses and minuses. I decided not to have one on my present boat.[/QUOTE said:


> A big plus for a topping is going aloft. I must prefer to use a substantial one with the main halyard as a safety. That little bit of extra height is worth it.


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## jgeissinger (Feb 25, 2002)

Ditto. 16 or so years ago I put a rigid vang on because it was the latest, coolest thing. Now I find that a topping lift is simply more useful in more circumstances.


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## MarkSF (Feb 21, 2011)

casey1999 said:


> Yes, I saw a similar comment in another post. Another poster said he nearly fell overboard when grabbing the boom to steady himself while reefing in rough weather. I have also seen recomendations my manufacurers to use the topping lift while at dock to take the force off the rigid vang's compression spring.
> 
> Say you are reefing (and have a rigid vang) and push down on the boom, will the boom drop any?


Yes it will drop. But surely you are never supposed to be using the boom to steady yourself?


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## casey1999 (Oct 18, 2010)

jgeissinger said:


> Ditto. 16 or so years ago I put a rigid vang on because it was the latest, coolest thing. Now I find that a topping lift is simply more useful in more circumstances.


What if you keep the topping lift, but add a rigid vang to help while reefing? Would you still recommend just the topping lift and not adding a rigid vang?


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## casey1999 (Oct 18, 2010)

MarkSF said:


> Yes it will drop. But surely you are never supposed to be using the boom to steady yourself?


Why not? In 10 foot or more seas you need to hold on to somthing while at the mast doing sail work.


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## endoit (Jun 20, 2010)

Great discussion. I have a topping lift on my Bristol 35.5 and the sailmaker advises a boom vang to improve sail shape. One of the units he mentioned is Hall Spars Quick Vang which for my size boat come in 12:1 or 18:1 purchase. Anyone familiar with this product please chime in as well as which ratio to choose. Thanks


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## MarkSF (Feb 21, 2011)

endoit said:


> Great discussion. I have a topping lift on my Bristol 35.5 and the sailmaker advises a boom vang to improve sail shape. One of the units he mentioned is Hall Spars Quick Vang which for my size boat come in 12:1 or 18:1 purchase. Anyone familiar with this product please chime in as well as which ratio to choose. Thanks


The 35.5 and 31.1 are very similar in the rig so these comments should apply to yours.

What I have found is that without the boomvang, the boom has a tendency to lift as the wind increases, and/or as you move off the wind, spilling some air especially at the top of the sail.

This is actually quite a desirable mechanism in SF Bay as it enables the boat to cope with gusts and strong winds nicely.

Applying some vang, especially from close reach to beam reach, is like standing on the gas pedal. The boat heals a lot more, the main develops more power, and the weather helm increases a lot, especially in gusts.

So the upshot is I can see why Bristol thought it OK to leave it off a cruising design. If I was singlehanding, and expecting stronger winds, I'd leave it loose. When I have crew we tend to play the vang sheet, trimming it when wind is <20 knots and easing it out when there's more. Generally it's the weather helm getting unreasonable that will have me telling the crew to ease it out.

Another board member advised having a cam cleat and enough line to reach the wheel, so you can adjust it quickly when you're on your own.

Finally, I think 12:1 is fine for a cruising boat. Not having too much advantage helps to not overstress the boom.

PS, I just brought the boomvang line back to the cockpit, next to the winch for the main halyard. Let me know if you want pics on how to do this. Basically though I used the same blocks as Bristol used for the main halyard, placing them side by side, so it looks like a factory job.


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## endoit (Jun 20, 2010)

Mark thanks so much for your reply. I am relatively new to sailing but last fall during the Annapolis sailboat show the wind gusts were in the thirties. The boat had the tendency to round up and spill, a real blast. I can see how a boom vang would prevent this and perhaps that is why the original circa 1978 model did not come with one. As folks started racing it became an add on. If you have pictures I would love to see your arrangement. I see a 31.1 at a local marina and just yesterday we were comenting that her lines are just beautiful.


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## MarkSF (Feb 21, 2011)

Here's a pic of the Garhauer rigid vang, installed (before I brought the sheet back to the cockpit)










Then a couple of the hardware. The Schaefer blocks haven't changed noticeably. The anodizing on the old cheek block has faded, otherwise they'd look identical.


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## puddinlegs (Jul 5, 2006)

Mechanical advantage is good. A 35 foot boat has much large loads than a 31 ft boat. Yes, a vang can break a boom. This usually happens in a hard round down and accidental gybe. Also if the boat is healed and or rolling and you stick the end of the boom in the water you break things. All that said, I wouldn't own any boat without a well functioning vang, and on almost anything over 30', a rigid vang. When you get yours installed, have a friend who's an experienced main trimmer go out with you and show you what it does to/for sail shape. On our boat, it's critical in certain wind ranges even sailing close hauled to the tune of about a knot of boat speed.


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## endoit (Jun 20, 2010)

Mark. Thank so much. Great pictures and she looks great. Wood finish is beautifull. My wife wants to know how you finished the teak. Boom vang it will be. New main from UK-Halsey, integral sail cover with lazy jacks, new electronics and off we go. Puddinglegs thanks also.


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## talbot (Jul 18, 2000)

Having just learned the hard way. I can tell you the weak link is the boom vang end fittings. Keep in mind with a rigid boomvang pushing up on it, the gooseneck needs to be able to keep the boom from twisting, even when a someone is hanging off the aft end of the boom trying to furl the sail.


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## MarkSF (Feb 21, 2011)

endoit said:


> Mark. Thank so much. Great pictures and she looks great. Wood finish is beautifull. My wife wants to know how you finished the teak. Boom vang it will be. New main from UK-Halsey, integral sail cover with lazy jacks, new electronics and off we go. Puddinglegs thanks also.


The teak is done the old-fashioned way - 7 layers of varnish! Since I bought it, I sand lightly once a year and apply a new coat or two. The most important part of the maintenance is that the brightwork is all covered when docked.


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## MarkSF (Feb 21, 2011)

talbot said:


> Having just learned the hard way. I can tell you the weak link is the boom vang end fittings. Keep in mind with a rigid boomvang pushing up on it, the gooseneck needs to be able to keep the boom from twisting, even when a someone is hanging off the aft end of the boom trying to furl the sail.


The Garhauer design looks pretty strong. The price includes mounting plates custom-shaped to fit the boom and mast.

I did have a swaged connection on the vang fail on my daysailer. The whole vang assembly shot up into the sky, and sank where it landed.


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