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Upward movement when lifting front crossbar.
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=25105		 Page 1 of 1
Author:  jimw00d [ Mon May 24, 2010 1:28 am ]
Post subject:  Upward movement when lifting front crossbar.
I have just replaced the rear-corner casting on my 1984 HC. I always wondered what might have caused the horizontal cracks in the old castings. Now I think I have found a possible source.

Holding the front crossbar, if I gently lift the boat up, I can see upward movement in both front castings. On inspection, I can see that the hole in the pylon for the pylon bolt is no longer circular but eliptical. This means that the bolt is no longer held by the hole, hence the upward movement.

Getting the new rear castings into place was a real effort and I know for a fact that they will not come off. Given this, what are my options?

Perhaps I could drill a new hole below the existing one? Perhaps I could "shim" the pylon. It has been suggested to me that I fill the hole with "10 /10" and micro-fibre and then drill a hole through the new material and bolt.

Any ideas?

The boat is old and I bought it to learn how to sail. I hope to replace the boat in a few years so it does not matter if I can't "un-do" what I need to do here.

Thanks
Author:  abbman [ Mon May 24, 2010 4:17 am ]
Post subject:  Re: Upward movement when lifting front crossbar.
You could epoxy the frame together. If you do a search on the forum you can find lots of info on this. My boat has been glued together and I feel that it is pretty stiff. If I lift up on one bow, the other one begins to come up almost immediately. You can really notice the difference when you are flying a hull going through waves. I think this process would eliminate the need to re-drill anything.
Just remember if you decide to do it, it is more or less a one shot kind of thing. It is very important to make sure the boat is all square before the epoxy hardens. It can be undone, but it is messy.
Author:  waldorf [ Mon May 24, 2010 10:25 am ]
Post subject:  Re: Upward movement when lifting front crossbar.
i had the same issue... i filled the top of the pylon with epoxy and re-drilled .. don't forget to keep the breather hole open if you do this... Cheers
Author:  s30series [ Mon May 24, 2010 6:26 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
your hobie dealer sells repair kits for this....if you look at the thread i started that shows the progress of my rebuild, you will see exactly what im talking about.
Author:  jimw00d [ Mon May 24, 2010 8:31 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
The only problem here is that I can't get access to the pylon from above. If I can't remove the rear corner castings, which I have only just replaced, how I can remove the front castings to get access to the pylon. I really wouldn't want to try to remove the rear corner castings.

I really am quite desperate here. If the hole in the pylon and casting is 10mm approx and the upward movement is around 3 or 4 mm why can't I simply enlarge the hole and replace the bolt with a larger one. I mean will this seriously make a difference to the integrity of the pylon.

It has also been suggested that I buy some steel putty. This is like moulding clay which then dries to the strength of steel. I could enlarge the hole a little, try to ram as much of the stuff in the hole, redrill and then replace the bolt. Having said that the thickness of the pylon is only a 1mm or so, so it might not work or might not adhere to the foam inside the pylon.

Thanks
Author:  s30series [ Tue May 25, 2010 8:09 am ]
Post subject:  Re: Upward movement when lifting front crossbar.
jimw00d wrote:
The only problem here is that I can't get access to the pylon from above. If I can't remove the rear corner castings, which I have only just replaced, how I can remove the front castings to get access to the pylon. I really wouldn't want to try to remove the rear corner castings.

I really am quite desperate here. If the hole in the pylon and casting is 10mm approx and the upward movement is around 3 or 4 mm why can't I simply enlarge the hole and replace the bolt with a larger one. I mean will this seriously make a difference to the integrity of the pylon.

It has also been suggested that I buy some steel putty. This is like moulding clay which then dries to the strength of steel. I could enlarge the hole a little, try to ram as much of the stuff in the hole, redrill and then replace the bolt. Having said that the thickness of the pylon is only a 1mm or so, so it might not work or might not adhere to the foam inside the pylon.

Thanks


I don't understand why you think you wont be able to get the casting off again? big rubber mallet and some good whacking! i guess you can enlarge the hole, but you might end up cutting through the vent tube and you're going to have to cut through the foam plugs as well
Author:  jimw00d [ Tue May 25, 2010 12:10 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
Aside from the fact that the thought of having to remove the rear castings plunges me into a state of despair, I tried to fit them using a rubber hammer and it didn't work. In the end I had to use a large block of wood to ram them down.

I bought the boat to learn how to sail and I seem to spend more time trying to fix things than sailing. I will replace the boat in a couple of years so I am really looking for a solution to get me through this period. If I had to remove the castings, epoxy the front pair, etc, etc, I can see another couple of weeks fixing rather than sailing. I have two small children so I just don't have time or will to go through a long repair job.

Any more suggestions would be great.

I could raise the front casting a few inches (I know that without the pylon bolts I have a few inches to play with) and try shimming with some tin can or something similar. I could then increase the 10mm pylon hole to 12 or 14mm (it would have to be big enough to remove the worn metal).

Thanks
Author:  abbman [ Tue May 25, 2010 1:17 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
I hope that you find a solution that is inexpensive and not time consuming. I do want to clarify that the epoxy process is not terribly difficult, expensive, or time consuming. The actual process may take a couple of hours, then you just let the epoxy set. Fyi, once you've epoxied the castings to the pylons, the bolt is more or less there just for safe measure. That being said, I'm sure there are plenty of other ways to address this problem.
Author:  s30series [ Tue May 25, 2010 2:00 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
go to home depot and buy some new bolts that are bigger and drill new holes...if you shear off the vent tube i guess since you said the boat isnt going to last too long it wont be a big deal
Author:  jimw00d [ Tue May 25, 2010 8:34 pm ]
Post subject:  Re: Upward movement when lifting front crossbar.
Thanks for all the great information. If I had noticed the movement before replacing the rear castings I would sure love to give the epoxy method a go. Fingers crossed the new larger bolts do the job for me.

Thanks again.
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