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PostPosted: Mon Apr 29, 2019 12:43 pm 
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Joined: Sun Apr 28, 2019 9:31 am
Posts: 3
Location: Wenatchee, WA
Hobie 20 newbie, dealing with some corrosion and needing advice.


The dolphin striker rod is loose, and I have no experience with the adjustments that would tighten it. The Hobie literature makes me think dolphin striker post would need to be lowered. Is that true?
https://imgur.com/Ykk91bg
https://imgur.com/w9cXQvB


The instructions manual lacks details. I’m not sure how the post would normally move within the compression sleeve, so I’m asking for advice on how to do that.
https://imgur.com/6f5BnSh



Also, in the photos below you will see there is corrosion affecting the threads in my dolpin post. I can turn the dolphin striker nuts, where the post meets the front crossbar, but I’m not able to turn the post itself.
https://imgur.com/F8jqrRW
https://imgur.com/UQgw3eH



I’ve read how other sailors have ground or cut off parts of the assembly and hammered the post and/or compression sleeve up through the front crossbar, from below. It’s not clear to me if I need to do all that.



Thanks,
Kevin


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PostPosted: Mon Apr 29, 2019 2:04 pm 
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May be more trouble to tighten and cause other issues. That fitting that "connects the rod and post will always rattle. There is no load on it. If the post is fused... the only other way is the nuts at the ends of the rod inside the crossbar. The requires removing the crossbar from the hull and removing the internal bolt compression sleeves.

The striker will tighten when the rig is up. It prohibits the beam from bending too much and maybe it is OK as is? The adjustment was to get a very slight upwards bow in the beam... barely.

To replace the post would require cutting it off below the beam. Then sliding the top part down and out of the beam.

We do have a few posts and the compression sleeve in stock.

https://static.hobiecat.com/digital_assets/PARTS_20_1.pdf

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Former - Director of Parts and Accessory Sales
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Hobie Cat USA
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PostPosted: Mon Apr 29, 2019 4:17 pm 
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Location: Wenatchee, WA
Matt,
(1)
do you have any photos of a dolphin post and compression sleeve?
I'd like to know what those parts look like, so I can understand where the threads meet because I don't see how the rod or sleeve would slide down.

(2)
Is it really necessary to remove the front crossbar from the hull to access the nuts at the ends of the dophin rods?
It seems like a very long socket wrench extension (or a combination of extensions and a socket joint connected together) could reach those nuts from the ends of the crossbar. Do those nuts adjust the tension on the rod?

Thanks,

Kevin


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PostPosted: Mon Apr 29, 2019 4:19 pm 
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Location: Eagle, Idaho
Don't be in a hurry start soaking it with penetrating oil. Let it sit for days and maybe you will get lucky.

Also Scott recently posted in the want adds that he has some crossbars for sale.
https://www.hobie.com/forums/viewtopic.php?f=7&t=64602

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PostPosted: Mon Apr 29, 2019 4:32 pm 
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Location: Jersey Shore
Below is a re-post of a reply I gave on a similar discussion on Hobie 17 front crossbars a while back. The 17 and 20 dolphin striker designs are very similar. If the nuts on the post are frozen, it is almost certainly due to corrosion and will probably be a lot of work to get things freed up...

srm wrote:
Since we're on the topic of front crossbar corrosion, I thought I'd add some info about the dolphin striker. If you've ever tried to adjust or remove the dolphin striker post on a H17 and couldn't understand why it wouldn't budge, the reason is almost certainly galvanic corrosion...a lot of it.

There is an aluminum sleeve that slips over the stainless steel dolphin striker post inside the front crossbar. The purpose of this sleeve is to transmit the force from the upper dolphin striker post nut down to the bottom of the crossbar extrusion. This holds the post firmly to the crossbar and also prevents over-tightening the nuts and crushing the crossbar. The hole in the bottom of the crossbar is slightly larger than the diameter of the dolphin striker post, and the hole in the top of the crossbar is slightly larger than the outside diameter of the sleeve. The problem is that, if you've ever sailed your boat in salt water or if your crossbar has been assembled for any significant period of time, galvanic corrosion between the sleeve and the post will seize the two together.

Since the bottom hole of the crossbar is too small for the sleeve to pass through and the bottom nut on the post prevents the post from being lifted upward out of the crossbar, the post will be stuck on the crossbar. The only way to remove the post is to cut off the bottom nut. Then the post and sleeve can pass through the upper hole in the crossbar. This is what I did and here's what I found when I cut the sleeve off of the post...

Image

Image

The post had a continuous band of corrosion residue all around the contact area of the sleeve. My plan when I reassemble the dolphin striker is to coat the post in a generous amount of tef-gel antiseize. I may also use a piece of thin walled heat shrink tubing over the section of the dolphin striker post that contacts the compression sleeve to act as an additional galvanic barrier and hopefully allow for easier disassembly in the future if necessary.

sm


sm


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PostPosted: Thu May 02, 2019 11:34 am 
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Location: Wenatchee, WA
Corkguy:
I’ll give the penetrating oil a try before I do anything else. If the penetrating oil does work, how will I know? Do I put Vise-grips on the dolphin striker post and try to turn it?

sm:
Thanks for the photos. If I get to the point where removing the dolphin post is necessary, then why would I have to cut the bottom nut? You can see from my photos that the top and bottom nuts are free. I can unscrew them.
Once the top and bottom nuts and washers are removed, do I then apply pressure to try and persuade the entire dolphin post and compression sleeve to raise up together in one assembly through the top of the front crossbar? I’m imagining a floor jack would work, with a little creativity. Is that what you did?


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PostPosted: Thu May 02, 2019 3:55 pm 
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Joined: Tue May 27, 2003 12:44 pm
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Location: Oceanside, California
If the oil works you would be able to tighten the lower nut and see the post move down to tension the rod.

Quote:
persuade the entire dolphin post and compression sleeve to raise up together in one assembly through the top of the front crossbar?


Two things. The lower nut can not thread down the length and come off the post below the beam and the compression sleeve only comes out the bottom of the crossbar. The hole on top is the diameter of the post. The hole on the bottom is the diameter of the compression sleeve. Since it is likely fused to the post (picture shows a lot of corrosion) the post has to come down and out of the beam as a "single piece". You can't raise it to get above the retainer cup either.

You could cut off the post cup / sleeve as an option. Then you would have to modify a new one to retain the post on the rod.

Image

Cut out "U" shapes to slide down over the rod and then drill for a pin to hold it down.

The part is 61140000 SLEEVE DOLPHIN STRIKER US$ 10.19

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)


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