GP14 Sailing Forums Forum Dyform Stays

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    • #6130
      dhfraser
      Participant

      Can anyone tell me the difference in readings that should be expected when using a loos gauge between dyform wire and normal stranded wire.e.g For 400lb on normal wire I would be looking at a reading of just over 28 on the Loos Gauge.I am thinking that as Dyform is stiffer then at 400lb the reading will be higher on the gauge or does anybody have an accurate..ish number on the Loos Gauge for 400lb with Dyform wire.

      Duncan Fraser

    • #6162
      Mike Senior
      Participant

      Hi Duncan, my thought process (probably wrong, hopefully an engineer will be able to correct me) – for a material of the same diameter when pulled to the required tension the reading would be the same regardless, but the amount of rope needed to pull that tension will differ depending on the stretch characteristics of the material. There will then be a performance difference in the materials when sailing reflecting how the material reacts to changes in load on the rig, meaning the dyform wire should be more efficient if you are looking to maintain a consistent tension as it stretches less than conventional wire.

      Mike

    • #6166
      davidrowlands
      Participant

      Dyform wire rope

      Mike is correct, the tension developed in the wire rope for set up purposes will be the same as for a normal strand rope. I have not seen this question before but am doubtful that the dyform wire rope offers any improvement in sailing performance. This is because the wire strand for both conventional and dyform formats is not taken to anywhere near its yield point during sailing. Thus the claimed lower stretch on dyform (other than that imparted by the strand lay) will not be exploited.

       

      David Rowlands

      • #6167
        dhfraser
        Participant

        Hi Mike and David,

        Great to hear from you both.The reason why i have brought up this subject is as follows.The boat I have came with Dyform stays and I am sure that it was set up for 400lbs,however after getting the Loos gauge out after some time,I find myself measuring in the 450-460 range to my marks on the mast.Maybe I have dropped half a hole on the adjusting plates,somewhere along the way, but for me usually when I pull on the tension it goes on and then stops around the 400lb mark and that would be around my mark on the mast, to get more on you really have to pull hard.In the last day or two I have trolled various sites for info on this and the Snipe class and the Flying Fifteen class mention that there would be a different reading between the two wires.

        Obviously my main issue is that I am unnecessarily putting excessive load on my boat.Your explanations sound compelling so I will go back to my boat with a clean sheet paying more attention to marking up and making notes.

        Best regards

        Duncan

    • #6222
      Mike Senior
      Participant

      Hi Duncan, I would guess that the gauge is correct. However, if the mark on the mast is from a different set of wires in the past then it is very unlikely the new set will measure the same, when pulled to the same mark, not only due to dyform or conventional but also whether they are exactly the same length. The mark on your mast will also differ depending on the genoa wire you are using. I personally always use the same luff wire with every Genoa (so my set-up remains consistent), but if you use different Genoas with different luff wires you would need separate marks for each Genoa 

      I wouldn’t worry about sailing with 450-460 lbs of tension unless your boat is quite old. I regularly sail in the 450 – 500 lbs range when it is breezy. You can tell if you have too much tension in the system when the boat feels “twitchy” when sailing close-hauld in light winds. If you are struggling to find a nice grove in lighter breezes then easing the rig tension generally helps for me as it adds a little depth to the genoa. (a little off topic but thought i’d add)

      Mike

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