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Mystery Boom Sound ?
http://www.hobie.com/forums/viewtopic.php?f=14&t=63668		 Page 1 of 1
Author:  emh161 [ Sun Sep 09, 2018 10:34 pm ]
Post subject:  Mystery Boom Sound ?
Hi All, Am very new to both this forum and Hobie Cat Sailing -- lots of questions to come. Recently bought an older ('83) H16 to get started and in spending time learning the craft by disassembling, inspecting, and making notes about things that might need attention and a good cleanup, as I was handling the boom and moving it around, I noticed some sounds that suggest something loose is sliding back and forth inside the spar.
The boom and all the parts viewable on the outside seem solidly connected and well sealed. Whatever is inside seems pretty permanently trapped as all attachments I found were riveted and the boom seems sealed tightly. (It floats, no bubbles escape) Whatever is inside that's moving sounds "soft" like maybe something sand like not like a solid clunking sound when I turn the boom from one end to the other -- a sort of swishing/sliding sound as whatever's in there slides from one end to the other. Anybody have an idea what I might be hearing? Do I need to care about it? Thanks!
Author:  Catfan69 [ Mon Sep 10, 2018 9:26 am ]
Post subject:  Re: Mystery Boom Sound ?
Possibly some old rivets that were replaced, drilled off the heads and pushed remaining rivet body in .
Then riveted piece back in place, if so, no worries...
Author:  hobiesrock [ Mon Sep 10, 2018 7:41 pm ]
Post subject:  Re: Mystery Boom Sound ?
Ya... my boom and mast both have rivets rattling in them. Sail it!!
Author:  emh161 [ Mon Sep 10, 2018 8:28 pm ]
Post subject:  Re: Mystery Boom Sound ?
Hmm ... Dead rivets. Sounds reasonable. Thanks!
Author:  Hobiewonkenobi [ Tue Sep 11, 2018 3:45 pm ]
Post subject:  Re: Mystery Boom Sound ?
My mast sounds like one of those rainsticks you can buy at science museums
Author:  emh161 [ Tue Sep 11, 2018 8:06 pm ]
Post subject:  Re: Mystery Boom Sound ?
Interesting, I was handling it again earlier today and listening to the sound carefully, While I'm way too new at this to rule out the dead rivets theory, the sound is more like a swishing sound than what I think would be a more metallic sound of pieces of metal colliding with the boom end caps.

Which suggests a question: Are the booms (and masts too) filled with some material that may be breaking down and sliding around inside? I've read that masts are buoyant, which I tested and found to be true in my pool, Also checked the boom and it floats. Checked for air bubbles that might indicate leakage and saw none even with the spars submerged. Let them float for an hour and reweighed them to see if any indication they took any water in -- same weight.

Question about rivets: Have read Hobie used/uses Monel rivets for corrosion resistance. Can anybody confirm that? If so, any suggestions on where to get them?
Author:  Hobiewonkenobi [ Wed Sep 12, 2018 7:46 am ]
Post subject:  Re: Mystery Boom Sound ?
emh161 wrote:
Interesting, I was handling it again earlier today and listening to the sound carefully, While I'm way too new at this to rule out the dead rivets theory, the sound is more like a swishing sound than what I think would be a more metallic sound of pieces of metal colliding with the boom end caps.

Which suggests a question: Are the booms (and masts too) filled with some material that may be breaking down and sliding around inside? I've read that masts are buoyant, which I tested and found to be true in my pool, Also checked the boom and it floats. Checked for air bubbles that might indicate leakage and saw none even with the spars submerged. Let them float for an hour and reweighed them to see if any indication they took any water in -- same weight.

Question about rivets: Have read Hobie used/uses Monel rivets for corrosion resistance. Can anybody confirm that? If so, any suggestions on where to get them?


There is a foam plug near the top of the mast but none to my knowledge in the boom. I think we've ruled out all other options. Your cat was used as a drug mule in the eighties and your boom contains a brick of Acapulco Gold.
Author:  srm [ Wed Sep 12, 2018 8:13 am ]
Post subject:  Re: Mystery Boom Sound ?
Old rivet shanks would sound like small pieces of metal rattling around, not a swishing sound. Drill out the rivets and pop the end cap off. It's easy and is the only way you'll know for sure. There should not be anything inside the boom.

To reinstall, use either stainless or monel 3/16" diameter rivets (you'll most likely need a heavy duty rivet gun to pull them). Or, if you remove the aft end cap, you could actually use aluminum rivets since there's very little load on that cap and all the load is inward anyway, so the rivets really just keep the cap from falling off.

sm
Author:  HobieMarty [ Wed Sep 12, 2018 8:21 am ]
Post subject:  Re: Mystery Boom Sound ?
"Your cat was used as a drug mule in the eighties and your boom contains a brick of Acapulco Gold."

Cha Ching!!!

Sent from my SM-G955U using Tapatalk
Author:  emh161 [ Wed Sep 12, 2018 6:26 pm ]
Post subject:  Re: Mystery Boom Sound ?
Acapulco Gold! That should be worth a few rivets replaced! Might even buy me a REALLY nice rivet tool.

Per my previous question, As I've never bought Monel rivets before, Are they readily available at the usual suppliers?
Author:  srm [ Thu Sep 13, 2018 2:30 am ]
Post subject:  Re: Mystery Boom Sound ?
Monel rivets are not required, stainless will work fine. If you’re worried about corrosion, use a dab of Tefgel under the head.

sm
Author:  hobiesrock [ Fri Sep 14, 2018 7:57 pm ]
Post subject:  Re: Mystery Boom Sound ?
Harbor freight sells a beefy rivet puller for cheap.
Author:  Catfan69 [ Sat Sep 15, 2018 7:34 am ]
Post subject:  Re: Mystery Boom Sound ?
hobiesrock wrote:
Harbor freight sells a beefy rivet puller for cheap.


That's where I bought mine a couple months ago.
Works well
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