Rigid Boom Vang Failure

[jviss]

Sailed from Tarpaulin Cove to Edgartown today; wicked windy and wet! Gusts to probably 30, maybe more, and chop at "the chops" off Martha's Vineyard.

Coming in we noticed the boom was resting on the dodger frame. Investigated after picking up a mooring (we usually anchor out, but we were beat and it was blowing.)

Found the vang had thrown the pin that retains the spring, and in so doing damaged the port side hole. See the pics, please. I found the pin on the coach roof!

Does anyone recognize this vang? I think it's a Forespar, but am not certain.

I'm planning on re-installing the pin at the nearest useable hole location. I'm hoping I don't fire the parts across the harbor in the process.

Thanks,

jv

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• jviss
• Aug 4, 2018
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• jviss
• Aug 4, 2018

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• jviss
• Aug 4, 2018

 

[dlochner]

Can't tell you what it is, but it is probably not a Hall Quick Vang.

 

[DougM]

I can’t be certain, but from your photo it looks like the white internal portion of the vang by the damaged hole is cracked. The whole thing might be toast. I don’t know if I would trust a repair which might cost more than a new vang.

 

[dlochner]

Looks like it could be a Nautos.

https://nautos-usa.com/collections/...1334-telescoping-vang-2-internal-relation-4-1

Might also be a Forespar, but the color is wrong. Forespars are white.

 

[jviss]

Thanks Doug. That's a keen observation. I think you are right. I am going to try to take it apart (without killing myself) shortly, and try to at least get it working well enough to get home this week.

 

[jviss]

Looks like it could be a Nautos.

https://nautos-usa.com/collections/...1334-telescoping-vang-2-internal-relation-4-1

Might also be a Forespar, but the color is wrong. Forespars are white.

Oh, thank you. I will try to find a manual.

 

[jviss]

Update.

First, thank you very much to all who contributed to this thread.

I determined from the faded label in the morning light that it's an Offshore Vang from Offshore Spars. Makes sense, they made the mast and boom for this boat, too (as far as I can tell).

I think it was incorrectly installed/rigged. I don't think the pin should have been in the top hole.

I raised the boom with the main halyard to about 15º up, and the middle hole and the hole in the white nylon/Delrin follower nearly lined up. With a minor adjustment I was able to insert the pin. I released the halyard and the boom sat at about 5 to 10º up with no vang tackle tension. All good, I think.

I then stop-drilled the crack in the tube, peened-down the sharp edges, and safety-wired the pin.

I sent an email and several pics to Offshore Spars, asking if I can obtain the outer tube. (I should have asked for another nylon follower, I will if they follow-up.

Some more pics.

Thanks again,

jv

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• jviss
• Aug 5, 2018

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• jviss
• Aug 5, 2018

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• jviss
• Aug 5, 2018

 

[Scott T-Bird]

What is the diameter of that vang. (To me) It looks a little skinny for that size boat doesn't it? I'm thinking that pin assembly with holes thru thin-walled metal doesn't look right, either. Maybe there is a performance standard that is a little shy of the conditions you experienced. It would be a question in my mind, now that it has happened at lease once (that you are aware of). Perhaps an upgrade should be considered?

 

[jviss]

I declared victory prematurely. Even though I got the height right, the thing is now jammed. More investigation....

 

[Jackdaw]

@jviss, what is the role of the tube? Does it just provide (solid) support, or is there a gas or coiled spring inside making it a more traditional solid vang? As Scot notes the tubes seems very small for a 38 foot boat.

 

[Gunni]

That is a spring vang, undersized. Likely why someone set it up in the hyper-extended length. When the spring bottomed out. Boom, you toasted the vang. Get a bigger vang. In the mean time, you are back to using a topping lift.

 

[jviss]

It's a pair of telescoping tubes with a spring inside. There may be more complexity inside, as indicated here:

The internal purchase combined with with an an external tackle provides the high pull loads required to shape your mainsail. Additionally a stainless steel internal spring provides sufficient return force to support the boom with the mainsail flaked or furled. This allows for remove of or a rope boom topping lift.
​

There are three models shown on their website, but with no specs! They have three models, the #35 short, #35 long, and #45. Not sure which I have. I will probably call them today.

 

[Scott T-Bird]

There is no reason why you need to replace in kind, is there? I'd shop for other makers. I like the looks of Selden vangs.

 

[Jackdaw]

Additionally a stainless steel internal spring provides sufficient return force to support the boom with the mainsail flaked or furled. This allows for remove of or a rope boom topping lift.

Yea that's the part that seems undersized. The tube has to be of sufficient size to contain a spring (coil, shock or both) sized so that it can resists the full weight of the boom, sail, and a crewmate leaning on it. On the 36.7 its a coil/gas affair in a tube the size of my forearm.

 

[jviss]

That is a spring vang, undersized. Likely why someone set it up in the hyper-extended length. When the spring bottomed out. Boom, you toasted the vang. Get a bigger vang. In the mean time, you are back to using a topping lift.

That may be so. But, it has apparently been on this boat for 22 years. I suspect a lack of maintenance, perhaps a material failure, did it in.

 

[Steve Dion]

You may want to check out Garhauer Marine. They will make custom fittings for the boom and the mast end of a new vang.

 

[jviss]

All of the alternatives I've researched so far, including an exact replacement, are about $1000. Garhaurer will custom-make a polished, stainless steel, spring-based rigid vang for $495.

 

[jviss]

They will make custom fittings for the boom and the mast end of a new vang.

I'm betting Guido will make fittings on the vang that will fit my existing mast and boom brackets, if I ask nicely!

 

[Steve Dion]

Take photos of the mounting points and they may be able to replace your existing unit without modifications.

 

[Jackdaw]

All of the alternatives I've researched so far, including an exact replacement, are about $1000.

They want $1000 for that little thing? Amazing.