mast weight difference

Discussion in 'Sailboats' started by SeriolaDumerili, Dec 20, 2015.

  1. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    The gist I get is they are not interested in boat stuff anymore.
    dont listen and cant be bothered.
    Just helped replace a Marstrom on a multi that had the stupid carbon diamond rigging, which is what caused the failure in the first place.
    I never hear anyone talking about buying a Marstrom rig only hall and southern.
     
  2. bjn
    Joined: Jul 2014
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    bjn Senior Member

    Oh I see. That's a sad ending to Göran's life's work.

    Replaced with another carbon, or aluminum?
     
  3. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    it was a 2 piece one so got new top section
    Boat yard tells me they had plenty of arguments over the design..yard was right.
    There was other crap as well, spin pulley protruded the section so halyard goes down the side, thats just crap design. ( they did mod that on the replacement)

    Yes sad after all the great work and enthusiasm Goran put into that business
     
  4. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    Not for those particular masts, but some of the reasons are:
    Stock alloy masts cover a range of boats for each size. The mast might only just fit in the lower end of the range, so the mast is excessive.
    Larger dimensions usually mean thinner walls and less rigging.
    Some manufacturers/engineers vary the laminate along the length of the mast (alloy masts are the same wall thickness all the way up). Varying the laminate is harder to build, but uses less material.
    Build methods vary enormously. For example, the cheapest mast will be filament wound over metal mandrels, an automated process using low cost carbon tow. Most manufacturers cannot vary the laminate or the shape of these sections (we can) so they are heavy. The lightest method is to build in one piece in a female mould. This requires expensive carbon, skilled laminators and a lot of practice, especially if a sheer web is included.

    Seems like the likeliest answer. Perhaps it enabled less rigging/windage/weight as well. Or maybe the alloy one broke or was under specced.


    Most are all carbon. We have built unstayed masts for cruisers with glass off axis material to save cost at a small weight increase.

    All these would help. Biggest will be engineering the mast and laminate precisely for your boat. Carbon or textile rigging will also help. All are expensive though, so unless you are wealthy or serious about racing (clean bottom, practised crew, no junk on the boat, etc), it may not be worth the money.

    Other comments:
    Prepregs are not inherently lighter. They only become so if they are cured at high temperature and pressure. Wet laminates in the same circumstances are equally strong, stiff and light.

    An example of the above:
    We have just built a 15m wing mast for a 9m catamaran using high modulus carbon and resin infusion. The required sideways stiffness was calculated as 4 x 10^6 mm^4 with variations along the length. The nearest alloy mast was 5.45 x 10^6 mm^4 and was 20% fatter (ie less efficient). The next alloy size down was 2.7 x 10^6 mm^4.

    The alloy section weighs 123 kgs. The standard modulus tube 58 kgs. The high modulus tube weighed 41 kgs. This is a huge saving for a lightweight racing cat. We also custom designed and built the fittings and bonded them on, which saved further weight. The mast was infused in one piece including the sheer web. I have attached pics of the set up pre infusion and an offcut.

    This mast is not directly transferable to your boat, but does give an idea of the weight and windage savings that can be made.
     

    Attached Files:

    1 person likes this.

  5. pool
    Joined: Sep 2010
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    pool Junior Member

    Where would you put Lorima in your ranking, for quality and value, particularly for a multi?
     
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