Hello all. I'm pretty new to Hobie sailing.
I just picked up my 18sx a few weeks ago and have been picking away updating and repairing it.
One thing I noticed is the rivet joint on the mast seem to have some play in it. This is only noticeable when the boat is not rigged; however it makes me nervous sailing a boat with a mast that may not be so structurally sound.
Any tips on reinforcing the joint? Or will replacing the rivets do the trick.
Thanks....I'm sure this is the first of many questions...
Rob
Rivet Joint on 85 Hobie 18SX Mast
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Posted: Jul 20, 2011 - 09:12 PM
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Posted: Jul 20, 2011 - 09:49 PM
Depends a bit on where and why there is a joint in the mast. Normally the mast is a single extrusion (maybe with a comp tip at the top). If the mast has been repaired after damage and that is why the joint is there you need to check to see how it was repaired.
The normal procedure to repair a damaged mast is cut, sleeve and rivet (or tig weld) . You cut the mast and remove the damaged area, then you take a 2' piece of the same mast section and cut off the sail track. You then compress the section so that it fits into the original mast section and slid it in 1 ft and rivet into place with a number of monel or stainless rivet (i think they usually use 3 columns of three or some such. You can then slide the other part of hte mast over the 1 ft of exposed 'sleeve' and do the same for the top portion. Seal and you are good to go until corrosion sets in because you just used stainless rivets in an aluminum mast (not usually a huge problem in fresh water). So if that is what you have, just replace the rivets and you should be good. If the rivet holes are a little oversize then use some aluminum rivet sleeves. Or ideally get someone to tig weld the joint (ugly but stronger).
If the joint is not sleeved correctly or is sleeved with another section that is too loose you may have to acquire a piece of mast to sleeve it yourself or give to a pro to do.
If it is the comp tip then one of the hobie guys (damon?) will have to provide advice.
If it is the top or bottom casting you are talking about, then again re-rivet and seal.
Moral of the story. Hopefully not a huge deal but you have some work ahead of you. And get yourself a good wishbone type rivet gun and some 3/16" dia stainless or monel rivets.
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Dave Bonin
1981 Nacra 5.2 "Lucile"
1986 Nacra 5.7 "Belle"
Winnipeg, Manitoba, Canada
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Posted: Jul 21, 2011 - 11:45 AM
Hello and welcome to TheBeachcats.com, I missed this post when it first arrived.
It sounds like you have a loose comptip on your mast (stands for composite tip) which became standard on Hobie masts about 1985. After that the comptip was added as a requirement for class racing on all Hobie Classes so most older masts were retrofitted with the comptip.
The comptips have have about an 18 inch solid plug at the bottom that is inserted into the aluminum extrusion along with glue (not sure what kind), then the mast hound is riveted onto the top of the aluminum section with a bunch of large rivets, which also penetrate the fiberglass comptip base plug.
So if your comptip is "wiggling" the glue connection has broken loose and it is only being held on by the rivet backs. If that is the case, I'd recommend (carefully don't damage the hound) drilling out all the rivets, removing and cleaning up the comptip plug, then reinserting with the right glue/epoxy. (someone here probably knows the best thing to use).
Re-Rivet with closed back (waterproof) stainless steel rivets. You'll need a really long-handled or pneumatic rivet gun to pull large stainless sealed rivets.
Ha! One thing we have here is answers, use at your own risk.
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Damon Linkous
1992 Hobie 18
Memphis, TN
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Posted: Jul 21, 2011 - 04:00 PM
Thanks Gents!
I'll probably take the mast down on the weekend and take a closer look at the joint.
Any ideas on what to use for a glue or epoxy?
Hopefully the end of the comp tip hasn't worn to much... -
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Posted: Jul 21, 2011 - 05:27 PM
There is a package of epoxy from Hobie that is normally sent with each new boat when they are shipped to the dealers. Maybe your local Hobie dealer would have one or could order one for you. -
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Posted: Jul 21, 2011 - 05:51 PM
If it's your comp tip that is loose, follow, Damons instructions to completely disassemble it. I'd use thickened epoxy to glue it back on. That way you could potentially remove it later in one piece if you need to. 5200 works, but it's permanent. Hobie recommends Bondo which is polyester. I know of several repairs done with Bondo with good success.
There are instructions on retrofitting a comp tip on an older mast here that might help in reassembly:
http://2010.archive.hobie…rt/pdfs/13070100CTIP.pdf
Note that Hobie generally recommends that you do not weld on the aluminum extrusions (masts, booms, cross beams etc.). The aluminum extrusions are heat treated for added strength. Welding will weaken the aluminum in the area adjacent to the weld.
Hope this helps.
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Dave Wilson
Hobie 16, Hobie 14
Tampa, FL
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Posted: Jul 21, 2011 - 06:41 PM
If it's your comptip, and I'm betting it is, then you have the instructions. Drill carefully and completely. A couple of tiny little pieces of rivet or casing will convince you that this will never come out.
West System epoxy thickened with their filler if you have some, otherwise Marinetex, otherwise a bunch of tubes of hardware store epoxy maybe thickened with baking soda. Well hey, it's a fairly inert powder.
Stainless rivets are available. The "condoms" for them (rivet casings) are only available from Murrays according to me:
http://www.murrays.com/mm…e=19-5020&Category_Code=
Hobie put them in your mast when they built it. Seal everything with silicone when you put it back together. All the holes and the seam where the comptip goes into the extrusion.
