[Public-List] Reefing Cringle's

[John Irving]

The sail area further from the mast causes greater tension on the sheet than the sail area closer to the mast.  The center of effort from the sail area in the first reef would be further from the mast than the 2nd reef.  If the sail area of the first reef were the same as the second reef, the reduction in sheet tension would be more in the first reef than the second reef.

> On Apr 24, 2020, at 2:31 PM, Jonathan Bresler via Public-List <public-list at lists.alberg30.org> wrote:
> 
> If you are asking how far up the luff the reefing cringles are located,
> for Constance the first reef cringle is 4' above the tack and the second
> reef cringle is 8' above the tack.  This results in sail area reductions of
> 25% and 45% respectively.
> 
> Jonathan
> 
> Aside:
> Does the formula for pull on sheets (sq ft * kts * kts / 232) equate to the
> force on the sail such that a 25% reduction in sail area produces both a
> 25% reduction in sheet load AND a 25% reduction in force on the sail.
> Would think so, but dont know that I have ever seen it said so.
> 
> Jonathan
> 
>> On Fri, Apr 24, 2020 at 10:52 AM Gordon Laco via Public-List <
>> public-list at lists.alberg30.org> wrote:
>> 
>> Hello Greg,
>> 
>> That’s probably different in every boat.   If your boom already has
>> reefing gear mounted on it, those will be your guiding measurements.
>> 
>> Ideally you want the clew reef line to pull outboard along the boom
>> somewhat, rather in the style of an outhaul so that you end up with a
>> reefed sail that is flat, and there is utterly no load whatsoever on the
>> reef points, if you use them.
>> 
>> I’ve set up SURPRISE’s reefing so that the clew reefing line starts at the
>> end of the boom, goes up to the reef clew, then down to a cheek block on
>> the boom at a slight angle aft.  That way when the reef is pulled down, the
>> new foot of the sail is very hard tight and the sail is flat.   The working
>> end of the reefing line then runs up along the boom to a cleat near the
>> gooseneck, so it’s easy to reef whatever the position of the boom.
>> 
>> 
>> Gordon Laco
>> www.gordonlaco.com
>> #426 Surprise
>> 
>> 
>> 
>>> On Apr 24, 2020, at 10:46 AM, Greg Hounsell via Public-List <
>> public-list at lists.alberg30.org> wrote:
>>> 
>>> Morning Hive-mind!
>>> 
>>> Would anyone have approximate measurements for the distance of your main
>>> reefing cringles from the foot of the sail? My main is where I cannot
>>> access right now.
>>> 
>>> Cheers
>>> Greg H
>>> #592
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> 
> 
> -- 
> Jonathan M Bresler
> S/V Constance Alberg 30 #262
> Annapolis/Eastport MD
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