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Nacra 5.0 newbie - unable to remove bent mast support rod  Bottom

  • Just picked up a '94 Nacra 5.0 to replace my Hobie 16 which went "missing"(coincidentally a few hours after I got the Nacra I found my Hobie 16 disassembled and for sale on Craigslist - now I have two cats).

    The story of this Nacra was that it was used a few times on a fresh water lake in central florida then spent years under a carport. The keels are in perfect shape and no signs of any corrosion. However it has a bent mast support rod (I suspect the mast was not rotated when unstepping) and came with small Hobie sails).

    I am not having any luck removing the bent rod. The nuts loosened up easily (although the top is limited by the bend). However the rod will not move up and down. It spins freely. I had planned to cut the rod between the lower nut and the crossbeam and then simply push the top half up. However the rod will not budge in that direction so I have not cut anything yet. Could the compression tube(? aluminum) have fused to the stainless steel rod if lube was not used during assembly? I have been soaking it as best as possible with penetrating spray for two days without any luck. I do not see any obvious corrosion anywhere. Am I missing something?

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123102&g2_serialNumber=6
  • dr34994Could the compression tube(? aluminum) have fused to the stainless steel rod if lube was not used during assembly?


    I'm not familiar with the specifics of the NACRA assembly, but it sounds like that is exactly what happened. This is very common on certain Hobie models that use the same configuration of a compression sleeve inside the crossbar with nuts on the dolphin striker post which sandwich the crossbar. All it takes is a little bit of salt water between the (stainless steel) post and the (aluminum) compression sleeve and the aluminum will galvanically corrode and seize to the post. If that is the case, there is no amount of penetrating oil that's going to get the sucker apart.

    On the Hobies, the hole through the top side of the crossbar is large enough to pass the post and compression sleeve through, so all you have to do is cut off the bottom nut and the assembly will come out. Not sure if NACRAs are the same way.

    sm
  • The interesting thing is that I do not see any corrosion. I think the next step is to remove the front cross beam, cut off the rod just below the beam then with the cross beam on a support slowly try to tap out the rod without destroying the beam
  • You're not going to see the corrosion inside the compression tube. If you are going to try to "tap" the rod out, make sure to remove the rod out the top of the beam. The load and support transfers from the bottom.

    Try enlarging the hole on top of the beam and simply remove the bolt and compression tube all together. A small rotozip bit/rasp at a slower speed should get it done.

    --
    Philip
    --
  • What would be the point of cutting off the post before trying to tap it out? I only see down sides to this. First off I don't think you're going to be able to tap it out, but even if you could, what difference would it make if the post is cut or full length? And then of course, if you can't tap it out, now you're stuck with a crossbar that has a cut off piece of post stuck in the middle. At least if you leave the post full length, when you find out that you can't tap it out, you still have a dolphin striker post to work with.

    Which leads to my next question - why not just try to straighten the post?

    sm
  • I had thought about straightening the post. However I was concerned about either being left with a weakened rod or possibly damaging the crossbeam. This crossbeam is in really good condition. I am trying to keep the budget free for replacing the sails.

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123102&g2_serialNumber=6

    If I flip the cross beam upside down, place it on a board with a hole just larger than the diameter of the nut, this should help prevent damage as I try and tap out the rod. I could leave the rod intact and try the same thing to see if I can loosen it from the compression tube. Just have to aim straighter with the mallet.
  • Sorry, new to the forum, not sure why the picture is not posting.
  • I agree that trying to straighten the DS is very problematic, both to accomplish and then if accomplished the problems that it "may" create. This is not a piece that you would ever want to fail while sailing., Nor do you want to damage the main beam in this area in any way. So sorting out the correct fix is essential. I think you want to cut this DS rod below the beam and then replace it. A 4" grinder with a metal cutoff blade would handle this quickly. You can replace the DS with an OEM part or find threaded stainless rod and use it (easier/better to just buy the OEM part). Likely the DS was bent lowering the mast without having rotated the mast 90° to take advantage of the slots in the side of the mast base.

    --
    dg
    NACRA 5.2 #400
    This End Up
    Original owner since 1975
    --
  • dr34994Sorry, new to the forum, not sure why the picture is not posting.

    Welcome to the forum, I've fixed the images. The problem was you were using the url of the page the image was on, rather than the url of the actual image.

    In Chrome and Firefox you can right click (windows) on the image you want to show and select "copy image address" or "copy image location" to get the correct url.

    In Internet Explorer it's a little harder you have to right click, select Properties, then copy and paste the "Address:(URL) from the Properties dialog box.

    --
    Damon Linkous
    1992 Hobie 18
    Memphis, TN

    How To Create Your Signature

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  • I would tend to disagree with the above. I think there is little to lose by trying to straighten the post. You could probably slip a long, heavy piece of pipe over the post and bend it back. Consider that it took someone mis-handling the mast to get the post to bend like that (a very long lever arm). Under normal sailing conditions, the post is primarily under compression load in line or nearly inline with the axis of the post. Again, if you cut the top and bottom off of the post and you can't get the remaining piece out, you just junked your crossbar. I would want to have a high degree of confidence I could get it apart before destroying the post.

    That said, if you did decide to cut the post, one potential option would be to cut both ends exactly flush with the crossbar and then put a pipe or long piece of wood inside the crossbar and try to pop the remaining piece out sideways. I don't have a high degree of confidence that this would work, but it may be an option worth trying if you go that route. I don't think you're going to have any luck driving the post out through the holes. Once these things seize, they tend to be impossible to separate.

    sm
  • Thanks for all the advice.

    Happy to say I was successful in remove the mast support without damaging the beam. As an added bonus I figured out how to do it without having to disassemble the boat.

    I started by slowly "tightening" the top nut which in essence started pulling the support rod through the compression tube.

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123107&g2_serialNumber=3

    Once this was loose I took a hack saw and cut the rod flush with the bottom of the beam.

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123110&g2_serialNumber=3

    Look closly and you can still see the marks on the crossbeam marking the location for the hole.

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123113&g2_serialNumber=3

    Then kept turning the nut until it was free from the compression tube.

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123116&g2_serialNumber=3

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123119&g2_serialNumber=3

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123122&g2_serialNumber=3

    No damage to the beam, now have to get the compression tube out

    http://www.thebeachcats.com/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=123125&g2_serialNumber=3


    Now to figure out what sails to get!
  • Nacra North America has some surplus N500 sails on firesale. PM sent with additional information.
  • Looks like you got off easy as far as corrosion is concerned. Glad you got it apart. Here is an example of striker post corrosion I have seen in the past...

    http://i1108.photobucket.com/albums/h419/Fullsail18/H17%20Dolphin%20Striker/a2a937cd-164f-4e05-9b2f-ba5fbf9de1bb_zps1bbd8f28.jpg

    sm



    Edited by Dogboy on Jun 11, 2016 - 12:01 PM.
  • Yes after I got it apart I wondered why I had such a problem with hardly any corrosion (have lived on salt water all my life). I was lucky.

    RG7351, thanks for the nacra sail info. This is exactly what I need.
  • QuoteNo damage to the beam, now have to get the compression tube out

    No need to remove the tube, you will just have to get it back in the same place when you replace the DS rod.
    Get a couple of battery post cleaners,( small wire brush things on a rod), run them through the hole to clean the corrosion out, wipe some Tef-Gel (or similar product), around the inside of the tube, then install new DS rod.
    If you really feel you must remove the tube, just slide a 2x4 down the beam & tap it. the tube is the same length as the inside beam diameter, nothing but a bit of corrosion holds it in place. You will then need to tape it to a batten to get it back in place. One of my photos here shows the ends of the tube.
    http://www.thebeachcats.c…pictures?g2_itemId=73301

    --
    Hobie 18 Magnum
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    Mystere 6.0XL Sold Was a handful solo
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