Lack of Structural Bulkeads in centre cockpit yacht

Discussion in 'Boat Design' started by Guest, Dec 8, 2003.

  1. Guest

    Guest Guest

    I've got a centre cockpit yacht converted from a twin stayless mast rig (bow & aft masts were on bulkeads) to a masthead cutter rig. She is 38ft, 15t, GRP kind of like a Freedom 40.

    The builders/ naval architects stepped the mast using SST Post & tripod arrangement attached to coachhouse. The boat is going out of shape around the ballast line. She has internal ballast and a centreboard - I have opened her up and found rusting internal iron ballast - no doubt the main cause of the change in shape. Whilst she is all open I want to ensure that there is enough support in place for the modified rig. There is a lack of bulkeads in the saloon - and the one, that I thought would do the job finishes at the floor (as opposed to the hull) hence provides no real structural support.

    The repairers want to use an expensive SST ring frame linked to the chain plates - but I feel that this won't stop the hull changing shape as the ballast would still be within the ring frame. I think extending the salloon bulkhead to the hull and then using ribs (two or three) out of foam & polyester linked close to the chainplates might do the job.

    Any suggestions?

    Andrew
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It's difficult to say without more information. For example: thickness, core type and type of hull laminate, shape of the hull, position of the old and new rig. Also, if the cast iron is corroded and deforming the hull, there is more structural damage. Among other problems there will be delamination and possible laminate failure. Have you had a surveyor examine the boat?
     
  3. Guest

    Guest Guest

    Re: Surveyor

    No not a surveyor - I have had a naval Architect "Peter Lowe" have a look at it. He worked with Ben Lexcen ( Australia) in redesigning the rig in 1987 - but today works on bigger projects (http://www.peterlowedesign.com/) - he had little to contribute ... so far. Am continiuing to open the boat up & have taken a core sample that shows damage to the laminate about 30% through.

    Thanks

    Andrew R
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    A NA should be qualified to give you good advice. Did he have any comments about the keel?
     
  5. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Fix what is causing the deformation. This may require some epoxy on the cast work. If you feel the cast work needs some other thought, then talk to a designer.

    If the rust on the casting is causing this much damage then, something has to be done and probable has on other examples of the breed. Find out what works with the type.

    There are a lot of designs that have flaws that need addressing, and a few that showed their flaws in such a fashion that repair isn't an option. Find what kind of design you have and review it to the point of a business decision. Some times good, sound business decisions suck . . .
     

  6. Guest

    Guest Guest

    Thanks - have been weiging up all options. No reported issues like this in other vessels built... I'll keep at it. The ballast is not cast - it is a low grade IRON layed inside the hull. Getting the stuff out is a task - then the laminate can be addressed.



    ADR
     
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