Adding padeye to freestanding carbon mast

Discussion in 'Boat Design' started by Cat2Fold, Jun 10, 2012.

  1. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    I'm trying to add a spinnaker halyard close to the top of my mast.
    It is a 38' long carbon fiber tapered tube. The base is about 8" diameter with about a 1/2" wall. The top tapers to about 3-4", unknown wall thickness (sorry for the inaccurate measurements, boat is in Mexico).
    I was looking at padeyes to mount up there, and I was reading about mounting the padeye to a piece of g10 board and wrapping the g10 board with carbon tape around the mast and...
    Couldn't I just Use something like this drilled through the entire mast up near the top?
    http://www.westmarine.com/webapp/wc...&subdeptNum=50046&classNum=50054#.T9Q5fWt5mSM
    Seems like it'd be easier and should work.
    What do you all think?
    Thanks!
    Brian
     
  2. bertho
    Joined: Aug 2006
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    Location: asean archipelago

    bertho bertho

    Hi,
    did you check if any possibility to use a short dynema/spectra loop or belting strap to avoid any drilling/riveting on the carbon?
    can you access to the inside by the top of the mast ?
    cheer's
    bertho
    www.fusionschooner.blogspot.com
     
  3. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    I am always hesitant about drilling anything into CF. I have never gotten a good answer about it, but best practice seems to be to avoid holes, unless they were designed in.

    That being said, stainless and CF is also something to be avoided. CF is galvanicaly active, which is one of the reasons titanium parts have become so desirable. Since titanium is significantly more noble than stainless it helps to control electrolysis.
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Yep, I'd look closely at a Spectra gasket or lashing.
     
  5. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    Thanks guys,
    I'm not sure about access from the top of the mast. I'd assume so since the main halyard enters the mast in the front of the mast goes around a block that is through bolted inside the mast and exits the rear of the mast.
    I like the idea of some sort of lashing. It could be directly under the main halyard block, but how does one get it to stay put and not spin around the mast?
    I am wanting this halyard to raise and fly a fulrling drifter/genoa.
    From what I understand the luff rope needs to be pretty damn tight.
    Would the downward pressure pulling on the spectra lashing (of sorts)wedge it against the tapering mast and keep it in its place?
    Any pics of anyone running a similar set-up?
    Thanks again for all the help...
    Big B

    PS-I can probably find some pics of the top of my mast (or close) and post if that may help...
     
  6. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    Cat,

    I would find out the manufacturer of the mast and call them for guidance. Drilling into a carbon spar is just a bad idea, and a spectraloup around the mast, hoping the compression will keep it in place is a really bad idea. There are all types of shock loads, abrasion from the line, concerns about the block smacking the mast, ect that would need to be figured out.

    The manufacturer should be able to give some guidance on the best place to add an internal halyard, and how to go about it without damaging the structual integrit of the spar.
     
  7. sean9c
    Joined: Jan 2011
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    sean9c Senior Member

    Do you know if your CF mast was designed to be strong enough to take the load the spinnaker will add?
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I disagree, a simple rolling hitch will remain in place without moving, but this is a temporary solution. Gluing a lashing or sized gasket in place would fix its location for sure, though removal and replacement would require some work. Spectra and similar lines are replacing rigging metal wholesale on a lot of boats. Stretch isn't really an issue, strength and abrasion issues can also be easily addressed.
     
  9. bntii
    Joined: Jun 2006
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    bntii Senior Member

  10. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    Wow, I never even thought of using a rolling hitch. I assume I'd just tie on a turning block to the tail end?
    I like it. I am looking for cheap and easy to try out this used drifter I got. I can permanently afix the block when the boat eventually makes its way to my shop. As far as the mast strength goes... I do not know what it is engineered for, but I have flown a different spinnaker from the main halyard with no problems, the drifter will be for when the winds are light, and I'm pretty confident about the size and wall thickness of my masts being totally bomber. So, I'm not too worried about that...
    Can a Spectra (Dyneema) line hold a rolling hitch? It won't just slip?
    I see that Colligo Marine has endless dyneema loops. They have a 3" and a 4" diameter. I imagine one of those would work well if I new the exact diameter of my mast tops that are 1400 miles away from me...
     
  11. sean9c
    Joined: Jan 2011
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    sean9c Senior Member

    Looked at your site, really cool boat
     
  12. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    Of course it will hold Par, I was thinking of a permanent solution.

    Cat2Fold,

    Dyneema Loups are really easy to make. Like it takes two minutes to make them easy. The ones from Colligio are very well done, but there is no reason to not just spend some time working with dyneema and a splicing fid to learn how, that way you can remake them to any size you need as you go.

    Take a look at the long splice at http://www.keepitsoaring.com/LKSC/Downloads/dyneema%2Fspectra-splicing-manual.pdf you may need to shorten the bury depending on how large a loup you need, so I always recommend you throw in a lock stitch right at the crossover. But I still wouldn't consider this a long term solution. It might work to see how the boat sails with the new kite, but the wear on the mast from this would be pretty nasty over time.
     

  13. Cat2Fold
    Joined: May 2012
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    Location: Felt, Idaho

    Cat2Fold Junior Member

    Thanks Sean... Yup I'm very fond of her.:p

    For others...
    http://cat2fold.wordpress.com
     
    Last edited: Jun 11, 2012
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