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Topic: Rig Tension & Mast Rake |
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Spice312AndyPhelps |
Posted: 11-Aug-04 14:09 |
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At the traing weekend Ian P & Pete L agreed on the Rig Tension & Rake but I didn't write them down - care to re-enlighten me please gents.
I can then at least make an attempt at getting it close for the new jib using my dodgy old tension meter. |
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Simon Boyle |
Posted: 11-Aug-04 21:01 |
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Rake is 7.52m, reduced to 7.41m when overpowered - at least according to the instruction manual. For tension we need Ian. |
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Pete Lindley |
Posted: 11-Aug-04 23:24 |
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28 - 32 on the jib luff 350lbs - 450lbs. (Super Spars guage)
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Spice312AndyPhelps |
Posted: 12-Aug-04 09:37 |
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Ta |
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Ian Paterson |
Posted: 13-Aug-04 19:25 |
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I got my measurements from Chris Hames's newsletter some time ago ie Rake 7.490m, with 32 on the rig tension.I think I checked with Chris at the time that this was measured on the jib haliard. I use this unless its v gusty or windy when I have dropped the tension to 28. Following Pete's comments on mast bend to control main fullness I'll experiment further.
HOWEVER when we looked at different masts at Grafham at a previous gettogether, we saw that the length/angle of spreaders was very different between mast.Last w/end I thought Andy's spreader andle/lenght was very different from mine & Simon's. So you should check to see what your mast looks like when you try this. My mast is looks very straight from the gooseneck to the hounds with 32 and this rake. Yours might not.
Happy Bimbling!
Ian |
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Simon Boyle |
Posted: 13-Aug-04 20:44 |
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Ah yes, spreaders. Mine were very different initially with the spreader basically as far forwards as it would go. I now have 0.94m wire to wire at the spreaders with a depth of .171m from a string (streched tight from spreader to spreader) to the back of the mast. From memory this is mid way between Chris and Ian's boats and they seem to do OK! Maybe we could have a measure up at Queen Mary. |
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spice364 |
Posted: 15-Aug-04 20:46 |
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Just tried out the new sail and have banjaxed all my old settings, the new sail needs a lot more bend in the mast so i have had to move the spreaders back a notch to give me more bend in the mast, the boat points like a dream and seems very quick off wind to |
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Spice312AndyPhelps |
Posted: 18-Aug-04 07:23 |
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Having done some snooping around on spreaders I think we should really be talking about mast pre-bend.
A little knowledge is a dangerous thing – especially in my case – below is the little knowledge I have gained so watch out!
- Mast bend is measured by stretching the main halyard tight to the mast foot, and then measuring the maximum distance from the tight halyard to the mast track – rig tension on & swatcher off.
- Mainsails are cut to a base mast bend value – I’ve seen 2” quoted as a general value.
- Spreader length controls mast stiffness. Longer spreaders = stiffer mast = less gust response = fat blokes able to handle more power = thin bloke overpowered. So in theory you can tell how fat the owner is by looking at his spreaders! 
- Spreader angle & rig tension then provide the required pre bend for a given spreader length.
I’m nowhere near the boat so can’t offer a pre-bend start value – any offers or comments?
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Pete Lindley |
Posted: 18-Aug-04 10:13 |
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Don't forget a stiffer mast with a fat bloke might also be bad as the fat bloke might not be able to respond as quick as required by the wind and rig! |
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apawtionofshawts |
Posted: 18-Aug-04 19:06 |
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what are we trying to say about the fat bloke?? |
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