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Loose footed mains & Single line reefing on a 35-3

bayhoss

Member III
Watson here!

Well... not exactly. More like Frank. As my rough caculations have it - given the variables that: 1. The sail is not the same length as the boom.

2. The point of attachment for the sheeting is not in the center of the boom - affecting the curvature.

But, for a 12' boom with a very noticable deflection of 2.5" the reduction in boom length is only about 0.73".
Keep in mind that the exact position of the point of attachment for the main sheet and of the clew are being roughly but fairly estimated.

Best,
Frank

p.s. If the vang is tight, and the load is more to the front of the boom, will the later part of the boom retain more of its orginal shape? And would this bring curvature more forward?
 

Sven

Seglare
But, for a 12' boom with a very noticable deflection of 2.5" the reduction in boom length is only about 0.73".

Right, so the main is not flattened by the bend in a loose footed main, but the opposite.

Glad we got that settled :egrin:


-Sven
 

bayhoss

Member III
As I see it...

Sven that's how I see it. The truth of it is that unless you are using some form of high strength to flexure compound (like carbon fiber) by the time you flex the boom enough to have any serious change in the sail, the boom would either be permantly deflected or more likely snap in half. Unless that boom is very, very, long and has one heck of a low axial diamenter.

Best,
Frank
 

delwarne

Member II
I agree with Ted. Any boom bending, in any available direction, would shorten the distance between tack and clew and would loosen the foot of a loose footed main.
I think ...maybe
 

Emerald

Moderator
Just to cover all bases, in conditions that would have enough load to flex the boom, I would think that there would be more stretch in the sail and the control lines in the outhaul than boom flex, and that after making whatever baseline tensioning on the outhaul, any additional boom flex that might occur in a gust would be trivial to the sail shape given all the other places stretch could occur. Does this make sense or am I missing something?
 

Alan

Junior Member
I think that the discussion of boom bending has focused exclusively on the effect of the bending on the foot of the main. When the boom bends, the leech of the main would also be eased out by the bending, which would have a flattening effect on the main, somewhat like tightening an adjustable backstay on a fractional rig sloop. I raced a Lightning for 20 years and really valued the adjustable backstay for depowering the rig in order to keep the boat flat. It had a dramatic effect on sail shape. In 1985, it helped me survive over an hour of 40 to 50 knot winds on Puget Sound when the "black line" of wind showed up. I kind of miss that sail flattening ability on my masthead rigged E30-2, which has a loose foot. I do think, however, that the effect of boom bending on the flatness of the main would be somewhat marginal and is largely uncontrollable anyway.
 
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