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John949

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Everything posted by John949

  1. Your method sounds right but it is easy to check if you have got them right. The straight line distances from the half height point to the head and clew should be the same similarly the distances between the 1/4 point and the head and 1/2 point. Ditto 3/4 point and 1/2 height / clew. The 1992 version of the rules had a useful diagram.
  2. The phone number appears to be an electrical business answerphone. Is this correct?
  3. I was thinking of full size racing where ther is no requirement to call out sail numbers but it is often done but perhaps shouldn't be.
  4. Nearest common occurence would be the RO calling out numbers of any boats over the line at the start. This is often covered in local sailing instructions but could be considered outside assistance according to the letter of the law.
  5. APPROXIMATELY 660, you have to make the gauge if you want to be sure. My 10R and M fins are about the same length. I thought about making them interchangeable as the 10R is 400g heavier but don't want to start an arms race for club level racing. It may work for you but most people would suggest that a dual rated boat would suffer against a real 10R when the wind gets up. The overhangs increase the waterline length as the boat heels / starts making a significant bow wave and the forward one helps with nosediving allowing a bigger rig to be carried in a given wind strength.
  6. The rules give the dimensions of the gauage. The max length of the fin (to the bottom of the bulb is approx 660 mm from hull surface.
  7. Years ago (when I sailed high performance dinghies) there was a politically incorrect joke about someone froma certain part of Great Britain sending his mast back to Proctor's to have some pre-bend put in it. The joke being that pre-bend wasn't about putting a static bend in the mast but using the ring tension and standing rig set-uo to bend it according to the wind strength - under no load the mast is still straight. This is not the first time I've heard of IOMs using masts that have a static bend. I really don't see the point in this. If you need to bend the mast that much to get a good s
  8. On the subject of soft sails: This is a terrible definition. What does flat mean in this context? One can fold something over so that the top surfaces are parallel (into a U shape) but still leave quite a big gap between the two surfaces, is this flat? Surely creasing is damage (local yeilding for any metallugists). How is a measurer supposed to determine if the material has been damaged if visible changes to the material are allowed but invisible ones (e.g. microscopic cracks) aren't. Just to put the tin hat on it, what does 'ply' mean in the contect of a hetrogenous material like
  9. Sorry to bang on about this but a sail thickness rule will not stop fully battened rigs or indeed other areas of local stiffening. If you didn't like my appeal to the science of measuring the wrong parameter, here's a guide on how to make a fully battened rig with a sail thickness rule in place. The most simple rule would be ' The sail thickness shall not be greater than X'. Fair enough, but does this apply to seams? If it doesn't, then one simply creates seams wherever one wants to create stiffening and 'hides' a piece of stiffening material in the seam. If it does, then wh
  10. Brad makes an interesting statement which is worth considering in more detail: Marbleheads (and As) are not one designs so change is supposed to happen slowly over time. Marblehead design has changed beyond recognition over the years with the result that (most) boats over 15? years old are totally uncompetitive against modern designs. Allowing change lets the class evolve and remain viable in performance terms against current designs. The price you pay for this is that older designs are not competitive, so older (and cheap) 'beginner boats' are not really worthwhile and attracting n
  11. I don't think it's the thickness of a sail that's the issue, it's the flexibility of the material that matters. Of course thickness is much easier to measure but it's hard to come up with a good rule that is based on measuring the wrong parameter. If rule changes are being considered then we should also look at the term 'soft sail'. From an engineering standpoint, softness (cf hardness) is the resistance of the material to compression, not how easily it bends. For example, sponge rubber is soft, diamond is hard. If we do want to limit the stiffness of sails then the rule should state what
  12. Does their GPS software not do position prediction and therefore tell them if they can cross safely? I'm all in favour of innovation in sailing but we need to be careful that sailing doesn't become a contest in software writing rather than human skill.
  13. I watch it with the sound off and FF to about two minutes before the start because I find the commentary so banal, but each to his own. If you have Sky or Virgin then it's worth recording both the live and the replay versions as they frequently get delays and the live version can finish before the race does. The boat designs are interesting from a safety point of view as half the crew would be underwater in the normal capsized position. Let's hope there isn't anything for their clothing or safety lines to snag on.
  14. Thought I'd have a go at sailmaking but I'm a bit confused by a couple of points in the rules. 1) Width Measurement. The sail measurement diagrams show that the 'widths' are measured between the 1/4, 1/2 & 3/4 points on the leech and the nearest point on the luff. Simple enough but how do you find the 1/4, 1/2 & 3/4 points on the leech? Since the leech has a significant curve, do you have to measure round this curve, as that is a difficult to do in advance. 2) Leech Radius. The wording of J.6 is confusing to me. I think it's saying that you can have angles (or radii less
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