Mast Crack Photos

Discussion in 'Main Morgan 38 Sailboat Forum' started by datswite, Dec 1, 2014.

  1. datswite

    datswite Ken Ferrari

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    All - These are two cracks I found in my mast. I'm replacing the rigging and discovered them when I removed the shrouds. One is at the lower shrouds, and the other is at the upper. These are the compression tubes (duh).

    I'm working on getting some expert opinions, but thought I'd share the photos here for everyone's benefit and opinions on repairs.

    I'm leery to have them welded because of alloy weakening. But, we'll see what the pros say. This is the original Kenyon spar. The rest of the mast is still in pretty darn good shape. A bit of corrosion at the masthead welds, but it appears to be superficial.


    20145.jpg

    Lower Shroud Compression Tube



    20146.jpg

    Upper Shroud Compression Tube
     
  2. stnick

    stnick lee nicholas

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    I know a metal/Sailor expert I'll ask him..
    what i think he will say is weld a say 6 inch base over the bad spot and put it back together..
    I'll ask him tomorrow i promise..
     
  3. datswite

    datswite Ken Ferrari

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    Thanks, Lee. I've also got a few yards assessing the damage. The more opinions, the better!
     
  4. stnick

    stnick lee nicholas

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    I just got off the phone with my buddy Jeff the sailor welder .
    he said gouge it out and do a filet weld on it !
    Or better yet make a plate to go all the way around and weld that on , to strengthen the whole area.
    Plate like 3/8 or so .
    I'm sure all you spar guys will tell you the same thing.
    Hope all goes well. after all there years stress cracks are really normal..
    But no one wants to see them on there spar its just scary to the mind .
     
  5. maluhia

    maluhia Jim Ball

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    Just a question, it is a crack(s), or is it corrosion and abrasion? Certainly an inspection by a yard or surveyor is needed.
     
  6. datswite

    datswite Ken Ferrari

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    The top one (lower shrouds) definitely appears to be a crack. I didn't have a magnifying glass with me at the time, but the original photo zooms really well (photo resized for the this page).
     
  7. datswite

    datswite Ken Ferrari

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    Hmm... not sure what to make of this. I've spoken with a few different spar repair places, and I've received a few different opinions ranging from re-welding the compression sleeve to doing nothing.

    The "do nothing" opinion was based upon their experience that many compression tubes are never welded to begin with; the mast is simply drilled and a free-floating sleeve is inserted. The sleeve's only function is to protect the mast from being crushed by the rigging bolt. They suggested that the mast is fine, it's only the sleeve weld that is failing. Even if it were to continue to crack around the circumference of the hole, nothing bad would happen. I would just have a free-floating sleeve. They did not think that the crack would continue through the mast - only the weld.

    The second opinion about re-welding was couched in the following reasons:

    1. if the weld fails, the compression sleeve will no longer protect the mast (I'm not sure I buy this, the sleeve is still in the mast and cannot compress)

    2. if the weld fails, the mast might buckle

    (it should be noted that the guy specifically told me that he is desperate for work in the winter)

    Welding concerns me in that it can weaken the mast even further by undoing the tempering. Installing a doubler also involves welding. Riveting a plate involves inserting a dissimilar metal rivet into the mast exacerbating corrosion.

    Both solutions seem like they could make the problem worse. Either a weakened spar via heat or the crack continuing to spread.
     
  8. datswite

    datswite Ken Ferrari

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    Ok, 4th opinion... this time from Brion Toss.

    "Hi,
    Welding is a truly lousy option here, as it is very difficult to do without making things worse, is unlikely to make things better, and it will in any event destroy your paint job. The shape of the cracks indicates that the tube is indeed welded in. These cracks are very likely to continue to migrate into the mast wall, at the location on the mast where the standing rig loads are highest. I would drill out for shouldered bushings, and get compatible tangs for them. This will eliminate the fractured metal, and give a fuller bearing for the throughbolt.Said throughbolt will have its threads cut on a lathe, with nuts at both ends,such that the threads stop just outside of the tangs, thus no compression on the mast.
    Fair leads,
    Brion Toss"
     
  9. cadiman49

    cadiman49 Rick Noddin

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    Gents,
    I had a similar experience with my mast ('84 384, hull 47) but the orientation of the cracks was radial instead of tangential. It appeared that the cracks were contained within the weld bead, but it is difficult to tell without some test instruments. Not thinking that welding was a good idea, without a pretty well controlled process, I went with the suggestion of a good spar man, and made up two reinforcement plates from 3/16" thick 316 SS. Before attaching the plates, I drilled 1/8" through-holes at the end of each of the two cracks. The plates, curved to fit the mast, were screwed to the mast with 1/4-20 316 SS machine screws, "locktited" in. I will find out if the bolted fix is successful in the first good blow! I have seen rivets used successfully in the same application.
     
  10. maluhia

    maluhia Jim Ball

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    I would ask about dis-similar metals, Aluminum and SS. I would also ask is this, after 30 years, a real problem? Where are the stresses on the tangs but at a downward angle and go from port to stbd. What will fail?
     
  11. tfrere

    tfrere Thomas McNulty

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    I agree with Jim. The aluminum mast will corrode if directly attached to the stainless. You could put a gasket between them or use aluminum plate.
     
  12. tyree

    tyree New Member

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    I know this is an old thread butI have the same exact cracks on the mast on my 382, on both sides of the upper shrouds compression tubes. What did you end up doing to fix this? Also how did you get the thru bolt out?
     
  13. stnick

    stnick lee nicholas

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    After a fix , check your rigging tension ! One never knows how many uncontroled jibes were done ,and what stress this has caused .
    This is not normal and just maybe your rigger could give you some insight ! ?
     

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