RIGID VANG INSTALLATION

[bbrooks]

We recently purchased a 1989 C34 with a Gauhauer rigid vang.  After purchasing the boat, we discovered the boom was bent and it also appeared that the vang was mounted very far aft (about 54" or 4-5" aft of the bail at 50").

We have purchased a new boom and want to make sure we mount the rigid vang in the proper location.  We have read all the postings here in the forum and have talked with Gauhauer and Catalina.  Gauhauer tells us we have the right size vang for the boat. We have tried the method that has been suggested where you crank down the vang to the lowest point you want to sail and let it out a little bit and place that location on the boom.  Also the advice that the vang should be at 30-40 degrees to the mast.  If locate the vang at this location and then let all the vang off, our boom rises up 30-45 degrees in the air.  We do not see any other Catalinas with their boom this high with no vang on.

Can anyone give us insight into this problem? 

Any help would be appreciated.  Thanks - Brad

[Jon Schneider]

Brad, go with the first advice; theoretical angles don't mean anything.  You want to have a margin of error that let's you straighten the leech as much as posible.  Don't worry about how high the boom will be lifted if you let the vang go; you will never do that.  Remember, the upward lift of the vang has no impact on sailing; it's simply there to keep the boom from crashing to the deck.

[waterdog]

Any chance that you have an oversized vang?   Is your boom low?   This doesn't sound right.   I just installed mine this season and it mounts ahead of the bail and the boom goes up maybe ten degrees above horizontal.   Fully contracted it just pulls the leech nice and tight.  On which axis was the old boom bent?   Was it bent at the point of the vang attachment?

[waterdog]

Oh, and Brad, congratulations on your new boat!   Welcome to the best owners group you'll find.  You should get all the help you could ever need here.   Send your cheque to Stu and then you won't feel guilty about getting free advice.   

[Fou Du Large]

Yes  The rigid vang keep the boom to crashing on the deck...

But will help you to control the twist of the mainsail in very light winds.

[Jon Schneider]

But will help you to control the twist of the mainsail in very light winds.

You mean as in inducing twist when there isn't enough wind to actually do that?  Why would you want twist on a light day?

[Fou Du Large]

Ok i try to explain with my poor english...

When you try to laminate the air flow in the top section of  the main in light wind
You shurely remarked that the air flow (teltail)? (wool)? tend to return behind the sail... at the top section
With the rigid vang pushing the boom up the twist of the sail increase, and the telltail move up.
The rigid vang eliminate the weight of the boom on the sail.

On a lighter boat the result is  more évident, but i'm shure that the résult is the same on a C-34.

Ok wee don't talk about 1.5 knot but 0.3 - 0.5

[Jon Schneider]

That's interesting, Martial.  I hadn't noticed that, but I'll try it.  It seems counter-intuitive to spill wind in light air, but I'm always up for trying new things.