Alberg 30 Raising Main Boom

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Windcall
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Boat Type: Alberg 30 1969 Hull 397

Alberg 30 Raising Main Boom

Post by Windcall »

I am wondering what the effects would be on my Alberg 30 By raising the boom. 7", I realize I would have to have new sails made which I have to anyway. Hazard a guess I will lose about 1`0 square feet.
Would the center of effort enough to make the boat heel a lot more? a little ? not noticeable?

Would Raising the end of the boom 6-8" and cutting a triangle from leach to the foot and leaving the foot the same be a better idea? not sure what that would do. Would it possibly not affect the center of effort as much and make the boat heel more.

I am remembering right the sails drive is more affected by the Luff rather than the Leach. So taking nothing from the Luff at the gooseneck and just a bit from the Leach would be better?

Also would cutting this triangle from Leach to gooseneck affect the heel of the making it less? Alberg is stiffer at a sharp heel.

Thank you
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atomvoyager
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Re: Alberg 30 Raising Main Boom

Post by atomvoyager »

Someone good at math could calculate the increased heeling moment of raising the boom 7". The reduced speed would be only slightly noticeable on most points of sail in light air. You could make up for the lost sail area by going full battens versus conventional battens. Or just accept the reduced sail area and consider it a way to offset the higher center of effort. How much in real practical terms is hard to quantify. Make sure mast winch placement won't be an issue if raising the boom. I don't see anything wrong with keeping the gooseneck position the same and changing the cut of the sail by reducing the leech other than it looking odd. There may be some theoretical points that make a shorter leech undesirable but I doubt they would translate to something noticeable. Sail makers already cut most mains a couple degrees less than 90 so a few more shouldn't matter too much. If you're going to work with a US based sailmaker then these are good questions for him. I doubt you'd get any useful advice using a Chinese or discount loft. I'm assuming you want increased headroom under a bimini frame. 5'8" is achievable under a near horizontal boom. So I guess that makes you 6'3"? If not having a bimini, the boom headroom in the cockpit is not much of an issue. For most of us, 90 percent or more of our time aboard is in port when we can raise the topping lift to give any amount of headroom. When sailing it's only hard on the wind when the boom is sheeted in that there's an issue. Another option might be to raise the gooseneck a couple inches and change the cut of the sail slightly to achieve an extra 7".
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Vince124
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Re: Alberg 30 Raising Main Boom

Post by Vince124 »

This is timely information, as I was planning to do the same with new sails. In my case, I was trying to avoid injury from an accidental gybe, since my current boom height sits at about 5' 3".
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atomvoyager
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Re: Alberg 30 Raising Main Boom

Post by atomvoyager »

Another thought - seems like raising only the aft end of the boom 7" and recutting the sail instead of raising the gooseneck not only looks odd but is no advantage because the geometry of it means the very end of the boom is higher than it needs to be to clear the bimini or give headroom several feet forward of the end. Might as well raise the gooseneck.
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