Monolithic Vs Sandwich Powerboat Hull Bottom

Discussion in 'Fiberglass and Composite Boat Building' started by acasas95, Nov 22, 2015.

  1. acasas95
    Joined: Nov 2015
    Posts: 3
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    Location: SPAIN

    acasas95 New Member

    I need to keep weight down.

    Can I use core sandwich for the hull bottom safely???!

    Check this out http://www.yachtsurvey.com/cored_hull_bottoms.htm

    Boat characteristics : 15 m LOA, 3.2 m chine beam, 10 tonnes FULL , 8 tonnes LIGHT, 50 knots CRUISE, 60 knots MAX SPEED, 20 Deg dead rise,1700 hp. Full epoxy/carbon structure. Max local impact pressure between 3.5 up to 5 bar (extreme conditions).

    HELP, THANKS
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Seems like an opinionated article to make the author look good. I particularly liked the "hydraulic erosion" bit. He compares rot in a balsa core to the Grand Canyon. There is nothing wrong with cores. Like any other laminate it has to be designed, built and maintained properly.
     
  3. acasas95
    Joined: Nov 2015
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    Location: SPAIN

    acasas95 New Member

    Thanks for your fast answer.
    So far I performed some analysis and in order to keep the whole structure below 3 tonnes, I should use sandwich panels on the hull bottom.
    Do you know of any production powerboat for open waters for speeds over 40 knots that uses sandwich on the hull bottom?

    Thanks a lot
     
  4. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Interesting link here
    http://cpscindia.com/pdf/fINISHINGoPTION/Proper_core_installation_Part_III.pdf

    about the traps of balsa core building. It dispels some myths, and explains that a lot of 'failures' were "never-bonds" during manufacture. The same principles can be applied to most core builds.

    The name that springs to mind for a qualified core-designer including power craft using cores, Derek Kelsall
    http://kelsall.com/Designs/KSSCommercial.htm

    I found him easy to contact and get info from.
     

  5. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    All the Carolina Sportfisherman use cored bottoms. Mostly they are plywood. They get used really hard too.
     
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