Help Needed: Changing a keel step mast to a Deck stepped mast!

Discussion in 'Sailboats' started by jfranta, Feb 2, 2015.

  1. jfranta
    Joined: Sep 2008
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    Location: Mesa AZ

    jfranta Junior Member

    We are in need of a few letters stating the risks associated with changing a keel stepped mast to a deck step mast by cutting the existing mast off and making a deck stepped mast. No change in rig design. Boat and mast are 45 years old.

    We need letters from Naval Architects or Designers. You will be compensated for this.

    Please contact us at info@colligomarine.com
     
  2. gggGuest
    Joined: Feb 2005
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    Location: UK

    gggGuest ...

    Very strange request. What sort of boat are you talking about would be a help for starters. But why "a few letters stating the risks".

    The risks are surely minimal if the whole boat, mast and rigging are properly re-engineered by someone who knows what they are doing at one extreme and "Boat could fall apart and mast fall down" at the other extreme if the engineering isn't up to scratch. So wouldn't you be better spending your money on one NA who can do the re-engineering design properly than on opinions from several NAs who will almost certainly say "It depends"?

    But if you are the Colligo Marine at that domain you surely know all this...
     
  3. jfranta
    Joined: Sep 2008
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    Location: Mesa AZ

    jfranta Junior Member

    Sloop rig. Just need generic letters from someone unbiased stating risks. To be clear this is for litigation.
     
  4. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Wow.........
    You need to supply a lot more info.......

    Though it appears that you are shopping for expert witness on a public forum.:idea::idea: ... You "could" end up with a thread full of random & conflicting advice published here that "could" compromise your position......
    Even better take the request to SA!

    Jeff.
     
  5. jfranta
    Joined: Sep 2008
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    Location: Mesa AZ

    jfranta Junior Member

    No Expert witness needed. This is for mediation. We have nothing to hide really. All I need is a letter with a short explanation of Eulers formula as they apply to a sailboat mast structure. Simply supported beam vs a cantilevered beam. What are the risks with changing a 45 YO mast from a keel stepped to a deck stepped mast? I need some opinions thats all.
     
  6. rcnesneg
    Joined: Sep 2013
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    Location: Utah

    rcnesneg Senior Member

    All of the load is transferred to the stays and shrouds, instead of just part of it. I would be inclined to chop the mast a foot or so above, leaving a stump, with a metal sleeve, so the top part can be put back on and the metal sleeve can still hold some of the load for you. I'm not sure if you are simply wanting to be able to remove the mast or you want to clear out cabin space or what. Good luck! Be safe!
     
  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    If properly done the risk is zero. You need to get the specification of the original design and those of the modified rig. Otherwise, is like asking "how long is a string". There needs to be a comparison of designs and a good description and physical evidence of the failure. I have done hundreds of insurance claims, and just an opinion is not enough.
     
  8. whitepointer23

    whitepointer23 Previous Member

    Are you requesting on behalf of an insurance company. Sounds like a claim on a poorly modified boat. If you are from a legal or insurance firm you should say so.
     
  9. eastern motors
    Joined: Oct 2013
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    Location: Michigan, USA

    eastern motors Junior Member

    I think the whole points is there was no "design" for the deck stepped mast. Someone just cut the bottom 6-8ft off their mast and stuck it on top of the deck. What are the risks of doing that?
     
  10. jfranta
    Joined: Sep 2008
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    Location: Mesa AZ

    jfranta Junior Member

    The issue statement is above. Same mast, no rig changes, only cut off and made a deck step. Send an email if you want to help. We would like some unbiased opinions only.
     
  11. gonzo
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    gonzo Senior Member

    From an engineering perspective, the answer is: it depends. Opinions are worthless without a study of the before and after. Also, a physical inspection is necessary to assess whether there was a maintenance or operation issue that was the proximate cause
     
  12. philSweet
    Joined: May 2008
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    philSweet Senior Member

    The risk is that something bad might happen at a time, and under circumstances, that are different from when, and under what circumstances, something bad would happen to the unmodded 45 year old mast.

    The legal community is seldom interested in risk. It usually is concerned with actual, particular cockups.

    Are you pursuing a possible latent defect?
     
  13. JSL
    Joined: Nov 2012
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    Location: Delta BC

    JSL Senior Member

    Changing from a keel stepped (lower portion is a fixed end panel) to a deck stepped (pin end panel) should be checked. Get a professional to do the work. 45 year old?? you should check the entire rig to avoid a headache (literally... and figuratively).
     
  14. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    Although there may be opinions against, mine is that the operation involves some risk because it is not only about cutting the mast but other problems arise, including:
    - The mast was calculated with its lower end fixed and now only be pivotal (see JSL post).
    - The forces on the stays vary.
    - The deck was not ready to support vertical efforts transmitted by the mast. Now the deck is the only mast support (plus stays, of course).
    - You may have to reinforce the existing deck cross-beams, or perhaps add some. A cantilever-type structure should be avoided.
     

  15. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Hi John,

    That's a change of tack going from litigation to mediation in two posts..... Well done, one is so much better than the other. There's as indicated, fitting of a compression post would be required as well as assessment of the capability of the lower panel..... something along the lines of struts to the gooseneck area might be required.... as has been said, it depends......

    Regards from Jeff.
     
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