the laser class "one design" sails and spars

Discussion in 'Laser Class Politics' started by mattsterett, Jan 20, 2004.

  1. jeffers

    jeffers Active Member

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    Didn't used to be. Perhaps there is just 1 source now.

    Years ago the Oz produced spars were sought after because they were (apparently) stiffer. The black andodised spars also had a reputation of being quite bendy...believe those if you will though. For the average sailor it will make very little difference.
     
  2. AlanD

    AlanD Former ISAF Laser Measurer

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    Same specs doesn't = same durability.

    The alloy from batch to batch might have the same nominal composition, but is the amount of magnesium, silicon etc going to be exactly the same? No.
    The extrusion die will wear with age, meaning that the wall thickness will increase slowly with each pass of material through the die.
    Is the heat treatment (ageing process) going to be exactly the same? No, the room temp between summer and winter is different and that means the time spent at elevated temperatures is going to be different, which will impact on the degree of ageing.
    Is the thickness of the anodised layer impacted by the "freshness" of the chemicals. Absolutely.
    Now if this occurs at different factories around the world, each will be slightly diffent, but the end result is there will be no absolute repeatability in each batch of spares, whether it comes out of the same factory or multiple.
    The specs will fall into an "acceptable" range for the supplier and for the ILCA. Whether those specs are suitable for our needs is a different question and the short answer is the continued issues around the world of spars bending would indicate that this is not the case.
     
  3. CaptainAhab

    CaptainAhab Active Member

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    Every variable that you mentioned are true. I have often wondered if the tolerance issues around the world are inch/metric differences. Many of the products sold in metric country are what I refer to as "fake" metric. They are nominal versions of the inch measurement. In the US the tubes will be made to the inch scale. Perhaps in the other countries like AU and the UK they are made to the equivalent but not exact size on the metric scale. In AU 1/3 is true metric, 1/3 is fake metric(50mm tube not 2"(50.8mm), 1/3 is still inch. Going into a hardware store can be trying at times.
     
  4. AlanD

    AlanD Former ISAF Laser Measurer

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    They're our dies, made to our tolerences and not off the shelf stock.
     
  5. oztayls

    oztayls Member

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    I bought a new top and bottom section for the Masters Worlds in Brisbane last year and they were bent after the first race. I think it's impossible to make a Radial aluminium bottom section to the specs that will not bend. The Radial really does need a composite bottom section to solve this issue, like the Byte CII. Cheaper in the long run.
     
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  6. Sailorchick

    Sailorchick Member

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    They never used to be this soft. Older radial sections used to last for ages so it is doable within the specs.

    I've still got one old radial bottom section in the club that is well over 5 years old, absolutely straight just due to lots of use its very very worn at deck level and I wouldn't trust it in any breeze to not snap. (I'm letting a lad use it as a starter mast and pointed out the weakness, he doesn't handle breeze well yet so fine for him)
     
  7. AlanD

    AlanD Former ISAF Laser Measurer

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    There are plenty of straight radial bottom sections out there, but what is currently being supplied are bending very easily. I think what happens is when a die is well worn, the extrusions are thicker but still within tolerance and they generally don't bend, but when the die is replaced, the extrusions are thinner and they do bend easily. It then takes a few years for the die to wear to the point where they stop bending. It could also be that something else has changed like the ageing (strengthening) process has changed and isn't as optimal as it could be, but still within the allowable tolerances.
     
  8. CaptainAhab

    CaptainAhab Active Member

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    Alan,

    Do you have a feel for the increase in failures after the modern vang was introduced? Many people myself included use much more down haul since the new rigging. That may also contribute to higher overall rig loads. I sail a full rig so I've only seen friends bent radial lowers; however, I often flex my boom and pull the sail down to the boom in heavy air.
     
  9. AlanD

    AlanD Former ISAF Laser Measurer

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    No real difference, we're carrying possibly less vang than we were back in the 80's where we were using our body weight on the boom to tighten the vang and the vang could hit the gunnel. The only difference is that the vang and other control lines are now easier to adjust, I know my settings based on boom position, sail position really have not altered going upwind since the late 80's, despite the new blocks, the use of thimbles or the complicated rope system.
     
  10. sailchris

    sailchris Member

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