Boom Vang Mast Fitting Failure

[KZW]

I screwed up big time in a club race yesterday and am seeking help from anyone who may have experienced a similar problem. I managed to rip the vang fitting on the mast out, breaking the fitting in the process. I had it vanged down hard, wind at 60 degrees, 19 knots, when a 25 knot gust hit. Pop, out it came. We were debating reefing at the time. Yes, if you are thinking about it, you should do it. Big Mistake.

The fitting is held in by what appear to be stainless steel pop rivets. The local yard guy says he has a $200.00 pop rivet device, but isn't at all sure it will stand up to 1/4 stainless rivet.
Further, the holes are a bit larger due to the rivets ripping out. It should be 5/16 rivets to put it back but I cannot find anyone who
- Has a riveter that will do the job
- Has 5/16 stainless rivets
Tapping appears to be undoable due to the thin wall of the mast.

Anyone who has done this before or has any ideas?

 

[RichH]

Cut a small access window several inches up from the bottom of the mast at its side. Reach in (long tongs or long-billed needle nosed vice grips) and through-bolt the vang plate back in place using THICK and as large as possible washers; OR, two pcs. of barstock backing plates drilled and threaded to match the 'rivet' pattern on the vang plate. Fabricate an aluminum cover plate to cover the 'access window'.

You'll need to know exactly where the electrical through deck ferrule is located on the mast butt 'shoe' so you have maximum 'work clearance' inside the mast.

 

[woodster]

I screwed up big time in a club race yesterday and am seeking help from anyone who may have experienced a similar problem. I managed to rip the vang fitting on the mast out, breaking the fitting in the process. I had it vanged down hard, wind at 60 degrees, 19 knots, when a 25 knot gust hit. Pop, out it came. We were debating reefing at the time. Yes, if you are thinking about it, you should do it. Big Mistake.

The fitting is held in by what appear to be stainless steel pop rivets. The local yard guy says he has a $200.00 pop rivet device, but isn't at all sure it will stand up to 1/4 stainless rivet.
Further, the holes are a bit larger due to the rivets ripping out. It should be 5/16 rivets to put it back but I cannot find anyone who
- Has a riveter that will do the job
- Has 5/16 stainless rivets
Tapping appears to be undoable due to the thin wall of the mast.

Anyone who has done this before or has any ideas?

you may want to plug the existing holes and move the vang bracket up so the bottom hole on the bracket is 1/2 way between the first and second hole from the bottom on the mast and refasten by drilling and tapping new holes instead of pop rivets this time ...from the looks of you pic i suspect the original holes were drilled the wrong size to begin with or they didn't have enough grip length to start with ...they look to clean to me..... just a suggestion

 

[peter_ms]

you may want to plug the existing holes and move the vang bracket up so the bottom hole on the bracket is 1/2 way between the first and second hole from the bottom on the mast and refasten by drilling and tapping new holes instead of pop rivets this time ...from the looks of you pic i suspect the original holes were drilled the wrong size to begin with or they didn't have enough grip length to start with ...they look to clean to me..... just a suggestion

Just make sure you use UNF machine screws and the proper drill for the tap

 

[Doug4bass]

How about unstepping the mast and thru- bolting? Dont think thats a Garhauer vang...they would have replaced the mast fitting.

 

[Claude L.-Auger]

Cut a small access window several inches up from the bottom of the mast at its side. Reach in (long tongs or long-billed needle nosed vice grips) and through-bolt the vang plate back in place using THICK and as large as possible washers; OR, two pcs. of barstock backing plates drilled and threaded to match the 'rivet' pattern on the vang plate. Fabricate an aluminum cover plate to cover the 'access window'.

You'll need to know exactly where the electrical through deck ferrule is located on the mast butt 'shoe' so you have maximum 'work clearance' inside the mast.

Rich idea is good and fairly easy to do. I've done that to help with the connections since I have to step an unstep 3 times a year. As he says you'll need to figure out where the wires come through the deck. In my case, the wire ferrule is located towards the aft side of the mast. Might be easier to unstep and work from the foot of the mast as you be able to reach in with your hand. Good luck

 

[JK_Boston_Catalina310]

Here is a photo of the mast step. I am thinking of going the access point to deal with a wiring issue.

As to the pop rivets, they should be aluminum not stainless. It's an aluminum mast and you don't want dissimilar materials. I use an accordion-style rivet gun. Works fine on stainless or aluminum rivets.

 

[wufibugs]

As the holes are now larger, how about aluminum rivnuts? The are more robust than rivets and should make a somewhat larger flange inside the mast. Not a strong as through bolting of course.

 

[KZW]

Here is a photo of the mast step. I am thinking of going the access point to deal with a wiring issue.

As to the pop rivets, they should be aluminum not stainless. It's an aluminum mast and you don't want dissimilar materials. I use an accordion-style rivet gun. Works fine on stainless or aluminum rivets.

Marina maintenance fellow, who is quite reliable, said they were stainless. He is worried his $200 riveter won't handle 1/4 inch stainless rivets.

 

[KZW]

I tried Catalina Direct via e-mail but the template wouldn't recognize the characters I typed in their SPAM filter. So I called Catalina in Sarasota and talked to their parts folks. They've been very helpful in the past. They don't have the part. This is what they said:

"Your mast is a Sparacraft extrusion, built and assembled by Charleston Spars in Charlotte, NC. Their telephone # was 704-597-1502. For the last 16 years that would be all you had to do to get a bracket or repair information. However last year Wichard bought out and moved into that facility in Charlotte, and while you could still call there and ask, they don't seem to have the knowledge as that isn't their focus or what they do anymore. I think you would have better service calling another major distributor of Sparcraft products (Like Charleston Spar was) such as Rig-Rite in Rhode Island. Their # is 401-739-1140. They will have dealt with this before as it is their expertise.

Rig Rite didn't have the part listed on their web site, so I e-mailed them all the pictures and dimensions.

The Catalina folks didn't want to comment on methods to attach the new fixture. They said they never had to deal with this before. I've asked Rig Rite.

 

[weinie]

Un-step the mast and through-bolt it properly with fender washers.

 

[KZW]

Rig Right in Rhode Island has the part and it is on its way. They suggested filling the holes, moving the fitting down 1/2 inch, drilling new holes and use 1/4 stainless pop rivets to hold it in. They also thought the OEM pop rivets were too short, and this was the cause of the failure.

 

[Doug4bass]

Rig Right in Rhode Island has the part and it is on its way. They suggested filling the holes, moving the fitting down 1/2 inch, drilling new holes and use 1/4 stainless pop rivets to hold it in. They also thought the OEM pop rivets were too short, and this was the cause of the failure.

Wouldn't drilling another set of holes immediately below the current ones weaken the mast?

 

[Pompadi]

There is a product we use at work called a Nutsert, it maybe a good solution for you
See YouTube link.

https://m.youtube.com/watch?v=sz2yZNqGNqo

 

[KZW]

There is a product we use at work called a Nutsert, it maybe a good solution for you
See YouTube link.

https://m.youtube.com/watch?v=sz2yZNqGNqo

It would need to have a much longer reach, and be stainless steel. Rig Rite provided stainless 1/4 pop rivets with a 3/4 inch reach.

 

[KZW]

Wouldn't drilling another set of holes immediately below the current ones weaken the mast?

I can only tell you what the folks at Rig Rite, who make masts and spars, attached these types of fittings, and do similar repairs told me.

Further, there is a huge slot just above with the screw for the in-mast furling. If the mast is going to fail, that will be the place.

 

[KZW]

I used a 5/16" tap in the 1/4" and put in aluminum bolts with maximum strength Locktite (red). I cut the rest off with a Dremel emery wheel and used the wheel to cut the aluminum flush. I then dressed it smooth with a file. Finally I put in a small bit of epoxy to fill the threads where the holes had elongated.

I found a guy with a tool to install the rivets. He said he had just put in 100 SS 1/4" rivets while in a bosuns chair installing steps on a mast. If he can do that, he can put in the six I need. With luck I will be ready to go by the weekend.

 

[KZW]

Fixed. Sail tested on Saturday day. All is good.