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 Post subject: Broken Comp Tip
PostPosted: Mon Aug 21, 2017 3:29 pm 
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Joined: Wed Aug 08, 2007 10:20 pm
Posts: 53
Location: South Boardman, Mi
So, yesterday I was out for a nice sail, when suddenly, the top fell off.

Since it wasn't too windy of a day, I was able to lower the comp tip off the sail and sail back in with half a main sail and a jib.

Image

The mast had no obvious signs of damage, prior to failure, and it wasn't that windy of a day...
So, I am a little unsure as to why the comp tip failed. As such, I am a little hesitant to try to find a comp tip to replace it with.

I have heard that the H21 mast section is no longer in production. Did hobie use the mast section for any other parts?

Why did hobie use such a beefy section on the H21? (please say stiffness and sail shape)

Will a H18 mast suffice, assuming I can convince it to grow 2' longer?

~Joe


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 Post subject: Re: Broken Comp Tip
PostPosted: Mon Aug 21, 2017 4:20 pm 
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Joined: Tue May 27, 2003 12:44 pm
Posts: 11893
Location: Oceanside, California
That is awful! Although, the CompTip had to have some damage at some point. Those things are bullet proof. Thick.

We used H21 mast sections to make a more durable recreational platform.

Unfortunately, the 21SC CompTip is no longer available.

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Matt Miller
Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA


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 Post subject: Re: Broken Comp Tip
PostPosted: Mon Aug 21, 2017 5:43 pm 
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Joined: Wed Aug 08, 2007 10:20 pm
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Location: South Boardman, Mi
Matt,

Any thoughts on if I can inspect the rest of the comp tip for damage? I know that composites can be pretty good at hiding damage...
How susceptible are these masts to UV damage?

I measured the comp tip and the mast wall thickness.

H21 Mast Extrusion Thickness: 2.5mm
H21 Comp Tip Thickness near base: 5mm
H18 Mast Extrusion Thickness (taken in luff track): 2.0 mm

Image

Image

Image

Based mostly on the fracture pattern of the foam, I believe the crack started on the tension side of the mast. On an upwind port tack I believe this would be the front and starboard side of the extrusion. If my assumptions here are accurate, the crack started right at the interface between the aluminum and the comp tip.


I digress...
What I am trying to get at is, can I determine if the rest of the comp tip can be salvaged, or if I need to find other alternatives.

To this point the boat has been plenty bullet proof and withstood 25 years of use, now I just need to find a way to get another 25 years out of her.

~Joe


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 22, 2017 8:59 am 
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Joined: Tue May 27, 2003 12:44 pm
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Location: Oceanside, California
I think you could sleeve it and make it work. I don't think UV has caused any significant issues with these over the years. It is not carbon... just polyester and black pigment.

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Matt Miller
Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 22, 2017 1:53 pm 
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Joined: Wed Aug 08, 2007 10:20 pm
Posts: 53
Location: South Boardman, Mi
Thanks Matt.


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 22, 2017 3:25 pm 
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Joined: Sat May 02, 2009 5:22 am
Posts: 557
Location: Columbus, Indiana
My buddy may have a new 21SC comptip in Florida....he needs one for a 21SE and has the wrong....I will have him contact you. :D

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Bill 404 21SE
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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 22, 2017 5:18 pm 
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Joined: Thu Jun 16, 2016 2:15 pm
Posts: 50
Pull the stub out of the mast as nondestructively as you can... anything composite can be rebuilt stronger and better with more composite. Doing it without adding too much weight may be a little harder, but if I broke a comptip once, I'd be willing to have an extra few pounds of epoxy and fiber up top.

Randii (who sails a fully aluminum mast even though it is ~1.5lbs heavier than the comptip in the sideyard)


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 Post subject: Re: Broken Comp Tip
PostPosted: Wed Aug 23, 2017 5:56 pm 
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Joined: Wed Aug 08, 2007 10:20 pm
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Location: South Boardman, Mi
Bill,

Thanks for the reference. That would certainly be a lot easier than splinting the spar.

Joe


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 29, 2017 1:28 pm 
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Joined: Sun Jun 21, 2009 7:32 am
Posts: 331
Location: Lake Gaston, NC
I've never worked on an SC spar, but it looks like the rivets for the tang are helping hold it in place. If you need to drill the rivets out, don't start drilling, and then wallow the bit around to clean out the rivet remnants. Start a hole with a cobalt bit the same size as the rivets, then use that as a seat for a pin punch the right size to punch the rivet through the hole.

I've done thousands like that, and it does not deform the rivet hole, so the original size rivet will fully engage the hole.

Check the specs closely to see if those rivets have caps, and select drill bits accordingly.

I would bet that mast has been dropped sometime in its life.

After the rivets are out, I'd use a slide hammer with Vise-Grips on one end to help it out. I'd use a propane torch on the aluminum-keep moving all about, but you may want a gentler source of heat to soften the adhesive. If it's epoxy, when you first start smelling it, start operating the slide hammer to see if it will start moving. The less damage to the aluminum, the better.


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Aug 29, 2017 3:48 pm 
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Joined: Sat May 02, 2009 5:22 am
Posts: 557
Location: Columbus, Indiana
My Hobie 21Se comptip has a 15" circumference at connection point and is 98.5" long, not including the top part with built in small block.

I hope this helps...... :)

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Bill 404 21SE
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 Post subject: Re: Broken Comp Tip
PostPosted: Mon Sep 04, 2017 8:13 am 
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Joined: Wed Jul 29, 2015 9:53 am
Posts: 32
Location: northern Lake Michigan
Was this the boat limping in on Lake Charlevoix? Saw it come in and made me cringe knowing my SC comptip has surface crazing that I'm hoping is truly surface only. Considering flying the jennaker with it's mast tang on the comptip itself. This makes me think/re-think. Sorry to see it and hope all were okay. Any damage to the mainsail? I have one I'm not using...
Tim
Petoskey, MI


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 Post subject: Re: Broken Comp Tip
PostPosted: Mon Sep 04, 2017 7:05 pm 
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Joined: Wed Aug 08, 2007 10:20 pm
Posts: 53
Location: South Boardman, Mi
Tim,

Yes, that would have been my boat. The sail faired quite well. It will only need a small patch over the bolt rope. I wouldn't worry too much about flying the jennaker. I would rather lose 1/3 of a mast while flying a jennaker than have it happen on a day too rough to fly the jennaker.

I honestly don't know what could have caused my mast to fail. When it happened the wind was not blowing that strong. I have put the boat through easily thrice the wind earlier in the year and I haven't dropped the mast or had any similar impacts.

With composites it can be really tough to tell if there is damage, and if that damage is significant. If you find a way to determine if your mast is OK, I bet there are some folks at Boeing that would love to talk to you. Since you likely won't be able to tell, don't waste your time worrying. If it does fail, sailing upwind becomes more difficult, but the boat is still very seaworthy.

~Joe


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Sep 05, 2017 6:05 am 
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Joined: Wed Jul 29, 2015 9:53 am
Posts: 32
Location: northern Lake Michigan
Thanks Joe, good to hear from you! Not sure I want to bring the mast to Seattle to have Boeing look at it... Funny! Maybe I can run it through the (Hobie) Cat scan at Charlevoix Hospital instead! It actually would fit :) just need to find the right diagnosis code to bill insurance.
I've been sailing mono-hulls for a long time and I'm definitely used to calamities big and small out on the water. Rarely is there not some issue almost every sail, but a broken mast is up there (or was up there before it broke). I do remember that day for yours was not too windy and we were wondering what happened. Just trying to accident-proof mine as much as possible, for sure.
Probably going to join the CRAM (catamaran racing assoc. Michigan) to see what the group is all about next weekend in Tawas City to get some on the water rigging/set-up/cat sailing tips from those guys and to have some fun too.
Take care,
Tim


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 Post subject: Re: Broken Comp Tip
PostPosted: Mon Sep 18, 2017 8:28 pm 
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Joined: Fri May 11, 2012 3:07 pm
Posts: 179
Why is the comp tip not available?


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 Post subject: Re: Broken Comp Tip
PostPosted: Tue Sep 19, 2017 11:25 am 
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Joined: Tue May 27, 2003 12:44 pm
Posts: 11893
Location: Oceanside, California
Discontinued product from the mid-late 90's now 20 years old. At some point the tooling fails as is the case here. Last one sold in 2014.

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Matt Miller
Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA


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