To Vang or not to Vang

[ihhartley]

Having owned several Monohulls, Sabre 22 trailer yacht and an Alan Wright Tracker my next boat was a totally fun Hobie 16, best fun for dollar, we had a fairly old one and the grown up family thrashed it. Now the question-Why do most multihulls not have a boom vang (or kicker), I can see that having a wide traveller is an advantage but why not a vang as well?

[Sonosailor]

I wondered the same, through Hobie racing into cat cruising. I can say that it makes less sense for a loose-foot main, and less sense for any situation when the main stays directly over the main traveller.

It also makes less sense when going down-wind or especially broad-reaching, when the speed/direction of the wind at the top of the mast is noticeably different than at the bottom of the mast. By the time I get all my telltales flying properly, all along the mainsail, there is no purpose to be served by a vang.

Having a second place to apply a downward force to the boom might help in some circumstances, but it just does not seem to come up enough to justify the extra rigging on a fast Hobie or on a slow cruiser.

Vang is a nice name for a german wolf-hound, however. Here, Vang! Good boy.

[Factor]

I too was wondering about this. I have just bought a 9 metre kendrick tri which has a vang and I am keen to try it out and see if it makes any difference at all.

[cat man do]

Sailed plenty of multi's , never seen a vang, or seen the need for one for all the reasons Sonosailor said.

Believe me , if another bit of string could have been run to get some extra speed, we would have had it.

Dave

[rtbates]

Maybe it's because cats are relatively fast and tend to keep the apparent wind forward. I also have a Hobie 16 and I never sail dead downwind. Much faster to sail off and gibe downwind.

[Alan Wheeler]

I think it is the size of the vessel you are comparing, than the fact it is Multi or not. Hence the 9m having the vang and the smaller hobie etc not. With a larger Boom, I don't see how you can controll it without a vang. It doesn't matter what the "apparent" wind is, the main sheet can and will not support the boom at the correct level. Especially as you let more sheet out, the boom will continue to lift in attitude if you have no vang to control it. Multi or mono, they are both the same.

[colemj]

Also depends on the rigging setup. If the main traveler is on deck and transverses the width of the boat (talking multi here), then the need for a vang might be considered reduced, but not eliminated. One purpose of the vang is to keep the boom from lifting when running off the wind. This is particularly important with multi's, where the shrouds are located quite aft and a sail twisting off due to no vang will chafe quickly. If the wind is always forward of the beam, and the traveler extends to the sides of the multi, then the mainsheet will provide some vanging.

Mark

[Tropic Cat]

One more reason is having a slightly baggy main sail. As noted, multi's often sail with the apparent wind forward. The vang helps with sail shape.

Rick in Florida

[cat man do]

Just looking at my pics of the go fast cat's and tri's and not a vang to be seen.
As I said earlier i've never seen one and i'm sure if they made a difference the go fast boy's would have 'em.

1mm thick clear plastic sewn over your sail where the batten rubbs on the shroud takes care of chafe , as does black high pressure plastic hose over the wire itself.


All the mains I've seen look pretty flat as well.

Dave

[delmarrey]

To take a wild guess, one has to think of the purpose of a vang. It's to keep the boom from lifting, in turn, keeping from loosing valuable air (on mono's).

On a Cat, especially small ones, one has to worry about sudden gusts and blow downs. WITHOUT a vang, a sudden gust would be cushioned by the boom rising, in turn, keeping the shock from the rig and time to avoid a blowdown. A bit like a shock asorbor.

My P$1.00......................................_/)

[Sonosailor]

I still say, especially with a fully battened main, that a full set of telltails will demonstrate the the curl in the sail is needed more often than it is not needed. The curl can also get the top of the sail out towards the beam, above the mast shroud tang, while allowing the rest of the sail to hang short of rubbing the shroud.

I think you're right that the looser boom can work as a shock absorber for gusts.