Thread: Discussion IOM General Discussion
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Old Mar 01, 2011, 03:25 PM
Ted Flack is offline
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This is one subject that go on forever. Some people like it some don't, I do.

Before I start my reasoning I want to make sure we all are talking the same language, pre-bend (to me) is forward bend when there is no load on the mast.

I only use enough pre-bend to give me the forestay tension, and therefore jib boom load at the the leech end. I want enough prebend so that I get the jib boom load I want without over-bending the mast with the back stay. Which could cause the top of the sail to invert and be very flat.

I am not a big believer in sails made for pre-bend or not. If I end up with with the mast with slight rearward bend or not really doesn't matter to me as long as I get the shape I am looking for in the top of the sail. So if the sail likes a straight mast I may want more pre-bend so that when the mast in straight I have the proper forestay load.

I usually don't tell my sailmaker anything, I ask him what I should use for pre-bend (or not). He is the one with all the experience.

If you want to discuss load on the leech end of the jib boom that can be an equally long discussion. All I will say for now is that I don't want my jib leech opening by itself because there isn't enough load on it. Remember the forestay and jib topping lift for a triangle and load on one effects the other.

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