Directwind.com

Voila un pote a moi veut se debarrasser d un mat d4 4.60 30% en bon etat , et moi il me manque un 4.30 pour une voile serait il possible de couper 30 cm ou c est trop? Quelqu un a t il deja fait  cette  experience? , car j ai pas envie de foutre ce mat en l air alors qu il pourrait servir en depannage , et si cela est possible ,quels outils utilisés scie sauteuse ou scie a metaux . Merci d avances pour vos réponses
[right][snapback]390134[/snapback][/right]

Some findings when measuring masts



Here is a link to some measurings of masts. Even if the measurings shown are selected, the figures are still mostly raw data - but here under you'll find some of the simliplified and generalized conclusions, you can make from the material:



The mast neither changes stiffness nor bend curve, as the temperature changes. Even though you by means of the IMCS test can't find any difference, if it is 0 degrees celsius or 25 degrees celsius, of course you might speculate, if the mast perhaps gets a little "slower" in the lower temperatures - that is if the "flex response" is dampened.



If you shorten the mast (from the bottom!), it gets softer and doesn't change its bend curve. Of course it's not wise to cut off so much that the mast foot/extension doesn't fit the mast - or that the boom is fixed above the extra strong boom area. And as indicated - never shorten the mast from the top.



If you extend the mast (with an extension), it gets stiffer and doesn't change its bend curve. Of course you shalln't  extend it so much that the boom is fixed beneath the beefed up boom area.



An example:

If your sail has a luff lengt of 510 cm, and the sail producer recommend a 490 cm mast (IMCS 29) for your sail, the findings mentioned above mean that in reality it doesn't matter very much, if you choose to extend the recommended 490 cm mast with 20 cm - or if you choose to cut off 10 cm from your old 520 cm (IMCS 32) mast. No matter what you choose, the result shall be almost the same: The 490 cm mast with extension shall have an IMCS stiffness of 30-31, whereas the shortened 520 cm mast shall also end up with an IMCS stiffness in the area of 30-31. Given that the 490 cm  mast and the 520 cm mast from their origins started with the same bend curve, the one solution equals the other - in that way perhaps saving you some money, you now can spend better elsewhere.



If your mast has become "excentric", this doesn't change the bend curve significantly. However, as the mast now is a little "pre-bend", it equals it has grown a little softer.



There is a tendency that the increasing softness that follow heavily use, are most noticeable in the areas that work the most - that is the top of the mast. But - you have to use the mast very much, before you face any problems in this respect.