New Mast Top Section

Discussion in 'Laser Class Politics' started by Tillerman, Nov 18, 2011.

  1. Tillerman

    Tillerman Member

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    When are we going to get a mast top section that doesn't bend in 20 knots?

    It's ready. It's been tested. It's just politics holding it up. What a mess!

    Check out Lasers - all bent out of shape.
     
  2. torrid

    torrid Just sailing

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    Methinks Global Sailing is waging a PR campaign.
     
  3. Eric_R

    Eric_R D10 Secretary

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    Clay Johnstone? You mean Clay Johnson?
     
  4. gouvernail

    gouvernail Active Member

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    Why Clay either of them??
     
  5. sprayblond

    sprayblond Member

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    Mouthwash with soap for all those who claim there was never a problem... What about the radial bottom sections..? Will they not bend with the new top section. I would hope and suspect so since the the composite top will have a more uniform bend force.
     
  6. Tillerman

    Tillerman Member

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    I am sure you are right. It seems as if Sail-World.com is the outlet where we are hearing Global Sailing's perspective on a number of issues affecting the future of our class. And we do need to keep in mind that usually only one side of the issue is presented there. But even if it is PR for one side, at least we are hearing something. The class leadership and LP continue to maintain their almost total silence.
     
  7. AlanD

    AlanD Former ISAF Laser Measurer

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    Bring the discussion to the main thread.

    Two issues, Clive believes that we are carrying more vang than ever before, because of the improved efficiency of the vang. In the old days we used to "super vang" by push down on the booms and pulling on the vang line simultaneously or the bigger gus like myself could just pull them on to that tension using the 4:1 system, definitely most guys weren't having an issue with getting enough vang once all the knot systems were developed and we were carrying 6:1. I don't believe that the amount of vang we're carrying has increased, particularly amongst the more competitive people, it's just a hell of a lot easier to pull on.

    From the metallurgical aspect, masts do no work harden by sailing work. It's a myth by the builders and dealers to cull the number of warranty replacements. For work hardening to occur, permanent deformation must occur, the metal must yield. Whilst deformation is occuring in the elastic region, no work hardening is occurring. It's all to do dislocation motion, a lovely area of metallurgy.
     
  8. suthera

    suthera Member

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    AlanD

    As always, your views, based on your considerable experience with the class, are appreciated on this forum by readers such as myself. But, for complete thick-ends like myself, can you re-express your last post in terms that those of us who don’t get tantalised by Metallurgy might understand?:)

    Cheers Much.
     
  9. AlanD

    AlanD Former ISAF Laser Measurer

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    It might be difficult, but I'll try. I apologies if I get anything wrong, it's been a decade or two, I'll fix it up tomorrow when I get home.

    The crux is:

    The builders / dealers theory requires the mast to be bent permanently, gets straightened, get bent permanently, straightened again .... get bent permanently, straightened again before it begins to gain strength where it resists getting permanently bent. A mast flexes in the elastic region and blockages required that inhibit dislocation just don't form, so the mast won't require more force to bend it permanently, than when it left the factory.

    Theory

    A metal grain consist of atoms which are in a crystal structure, each atom positioned in a precise location relative to other atoms in the structure, think of each corner of a cube (slightly more complex in almost all metals). However, sometimes there are defects with the crystal structure called dislocations. Dislocations are important because it allows rows of atoms to move relative to adjacent rows. Whilst not the same, but just from a mental perspective, think of two platonic plates sliding next to each other on an earth quake fault. Anyway, if the dislocations can move freely, the rows of atoms within the crystal structure can slide smoothly past each other allowing this permits elastic (non permanent deformation to occur) i.e. your mast flexing.

    When the metal is in the elastic region, the concentration of dislocations is very low. As the loads increase, more dislocations are generated and this permits permanent deformation to occur the number of dislocations can increase, they multiply. When you reach the point where the number of dislocations begins to increase, permanent deformation or yielding will occur. For your mast, this is where it will become permanently bent or at least until you straighten it.

    Dislocations can move along different planes, exactly which ones will depend upon the direction the metal is being loaded. When two dislocations meet they can cancel each other out, but more importantly they can also block each others movement and that will block following dislocations from getting past. For the following dislocations to get past, more force is required and this is really what work hardening comes down to. If you generate enough blockages, dislocations can't move easily unless a lot of force is applied and then the material will not easily deform easily.

    For work hardening to occur, you need a high density of dislocation to be present and this just doesn't happen in the elastic region, you need to be in the region where permanent deformation.

    I suspect you didn't really understand to much of that, but without lots of drawings and siting down with you for an hour or two it's a difficult thing to grasp.
     
  10. janson murphy

    janson murphy Member

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    I really like the idea but since the mast will be stiffer, wouldn't the vang purchase have to be increased?
     
  11. AlanD

    AlanD Former ISAF Laser Measurer

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    The masts aren't any stiffer.
     
  12. janson murphy

    janson murphy Member

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    Are you sure even with the carbon, or is it engineered so it just retains shape longer?
     
  13. 49208

    49208 Tentmaker

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    It's not completely carbon.. Carbon is probably less then 50% of the fiber..
    The design, engineering and construction was done by Southern Spars, arguably the most experienced composite mast builder in the business, even if it's not that complicated or challenging to replicate the stiffness and weight of the existing aluminum piece. We would just be doing what windsurfing did 20 years ago, switching to something more durable..
     
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  14. janson murphy

    janson murphy Member

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    I agree, Laser class needs to approve some other manufacturers, How much difference is 2 loops on a toestrap and 3rd party boom blocks really going to make?
     
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  15. AlanD

    AlanD Former ISAF Laser Measurer

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    Well, what have you personally done to get things officially changed. It's all very well whinging that the you think this should happen or that should happen, but unless someone takes the initiave and puts a submission to the ILCA nothing will happen, the best person to put forward the initiative is the person who wants the changes. Get off your a*** and do something about it.

    Looking at your other posts, I suspect that you really don't understand the laser concept, which is about competing in near identical boats and letting your sailing skills talk for themselves, rather than looking for the "perfect boat" that will win races for you. The class rules are set up so that the boats are near identical, there are are regional variations, but generally people are competing equipment from sourced from that region they are competing in. There are plenty of other classes around that will let you gain an advantage by be having the better boat, at your age I was designing & building my own Moths. Maybe it's time to assess whether the laser is the right boat for you.
     
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  16. sprayblond

    sprayblond Member

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    What are they doing in the back there..? And at a world championship.. Would the measurer approve this? I am sure those spars are not straight.
    !
    @ 7min:50
     
  17. Wavedancer

    Wavedancer Upside down? Staff Member

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    Those two are trying to straighten a (bent) mast. Considering that it has been pretty windy at least some of the time, that's to be expected. Nothing illegal about that, to my knowledge.

    Pretty nice video once you have suffered through the introduction...
     
  18. AlanD

    AlanD Former ISAF Laser Measurer

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    Definitely legal. If they went onto the water with a bent mast, then that is illegal.
     
  19. sprayblond

    sprayblond Member

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    And of course, lower mast was also straightened perfectly and mast did not bend during sailing. Whats the point in claiming it is illegal to go on the water with a bent mast when we all now it will be bent on the first upwind beat?

    And Alan.. I know the measureres only do what they are told to do i.e. measure according to class rules - but a little help from you guys in getting rid of the most obvious builder problems i.e. masts bending, bump in hull etc. could only help.
     
  20. AlanD

    AlanD Former ISAF Laser Measurer

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    We have no more say than you do. So what have you done in getting rid of the most obvious builder problems i.e. masts bending, bump in hull etc?
     

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