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Topic: Bent Mast? |
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Pete |
Posted: 13-Sep-05 07:15 |
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I am looking for my first ISO and have found one with a slightly prebent mast - the bend doesn't cause any problems with hoisting the mainsail but without another ISO at our club I can't judge just how bent it is! What are the class rules concerning prebend - I can't find any measurement diagrams anywhere and don't want to have to fork out for a new mast before going racing!
Thanks |
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Lloyd Walker |
Posted: 13-Sep-05 07:59 |
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Hi Pete as far as I can see a lot of ISO masts have some pre-bend. I don't think there is anything in the rules against it.(Bob will know). The main thing is I have found that it is not fast to have built in pre-bend. You cannot get enough leech tension if the mast is bent. The good news is if the mast is not kinked it can be straightened quite succsesfully. Put the mast over a sand bag or bag of compost on something high off the ground and two people(one at each end) can ease it back to shape.The sand bag goes on the fulcrum. If the mast is kinked then it is another matter it may brake and can't be straightened. Have a good look at it from the top along the sail track. The weight of the mast will make it bend a little but it should be a very even curve. Also there is some curve built in by the taper on all alloy masts which happens when the top section is cut and welded,be sure this is not what you are looking at. If your mast is not reparable I have one I could sell after the inlands. contact me at lloydandjoy@supanet.com |
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Pete Lindley |
Posted: 13-Sep-05 21:24 |
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Email me some pics
ISOFeedback1 at asafeplace dot co dot uk |
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Bob Ladell |
Posted: 13-Sep-05 21:42 |
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Lloyd's right - as you would expect the Nats Champ to be  - no rules on pre-bend and fixed pre-bend isn't good news unless it's windy.
Normal expectation is the the mast is straight between the gooseneck and tip when under 300lb mast tension and only the jib up. Any pre-bend would be derived from spreader angle - about an inch or so at spreader level is about all you would expect with max spreader rake.
Under no tension it should look straight in all directions. |
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Pete |
Posted: 14-Sep-05 08:31 |
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Thanks guys - it sounds like this bend is the result of some of that upside down sailing then. I'll have a good look to see if it can be straightened before buying! |
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