[C320-list] double main sheet control?

[Chris Burti]

I recommend Don Guillette's  Sail Trim Chart and companion
publication, Sail Trim Users Guide. You can order these at
www.Sailboatowners.com.

I found his explantions to be the best and most accurate that I've read.

s author of the immensely popular On Sat, Sep 15, 2012 at 11:38 AM,
Jeff Hare <catalina at thehares.com> wrote:
> Here are my thoughts, I have a lot to learn here, and there may be many
> different ways of looking at this or different explanations, so take it at
> face value.  Feel free to correct me wherever I'm wrong here.
>
> In my simple mind, mainsail trim all boils down these 3 things:  (anything
> more complicated than this and my head pops).
>
>   1) adjusting the tension on the three edges of the main sail.
>   2) trimming the boom in and out to get the leading edge of the main lined
> up properly with the wind.
>   3) adjusting the foil shape of the sail (DRAFT and DRAFT Position).. how
> flat or curved the sail is allowed to be and how far away from the mast the
> deepest part of the curve sits.
>
> LEECH SHAPE is how straight you keep the back edge of the sail. ( to
> controls twist).
> DRAFT is how much belly you have/allow in the sail  (controls amount of
> power generated)
> DRAFT LOCATION is how close to the mast the deepest part of the belly is.
> (controls how far aft the center of power occurs which acts like a lever
> against the mast)
>
> Now, controlling the three edges of the sail:
>
> Tension of the FOOT of the sail with the outhaul the sail helps flatten the
> sail somewhat. Lots more when you have a loose footed main.
> Tension of the LUFF with the Halyard and Cunningham moves the DRAFT LOCATION
> (forward I believe to reduce the leverage effect and stop rounding up so
> much).
> Tension of the LEECH with the mainsheet/traveler when going upwind, and the
> Boom vang when heading off wind controls twist.
>
> The mainsheet traveler can be pulled to way to windward, but the boom itself
> should NEVER (in my experience) be windward of the centerline.  Generally I
> find that if I needed to pull the traveler way up to windward, it's because
> I'm close hauled in medium light wind and want a little twist.  Without
> pulling the traveler up to windward, I can't get the boom centerline without
> pulling DOWN too hard on the boom and removing all my twist.
>
> Keep in mind when you're heeled, your sail isn't straight up and down, so
> the wind is running not horizontally across your sail but partially UP your
> sail, so look at the shape of the sail along the path of the sail the wind
> sees and look to optimize that foil.
>
> Alas, I always lose when racing.   Both times...  :)  But I like to cruise
> FAST.  :)
>
> -Jeff
>
> -----Original Message-----
> From: c320-list-bounces at lists.catalina320.com
> [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Dennis Harris
> Sent: Friday, September 14, 2012 3:24 PM
> To: C320-List at Catalina320.com
> Subject: Re: [C320-list] double main sheet control?
>
> Chris or others,
>
> On moving draft with mainsheet, please elaborate how/when this is done.  If
> boom height is controlled via vang, then it seems that mainsheet simply
> extends the range of movement of angle of attack greater than allowed with
> the traveler.
>
> Dennis Harris   C-320 #694
>
> -----Original Message-----
> From: Chris Burti
> Sent: Friday, September 14, 2012 12:21 PM
> To: C320-List at catalina320.com
> Subject: Re: [C320-list] double main sheet control?
>
> Proper sail trim dictates that you use the traveller primarily for changing
> the angle of attack, the vang for pulling the boom down or raising it to
> reduce twist, the mainsheet, outhaul and halyard/cunningham to move the
> draft of the sail forward or aft.
>
> If you wish to move the boom in heavy air without using the winch, either
> luff up a little or ease the vang to reduce pressure on the sail. Either end
> of the sheet may be used. Both ends of the traveler should be synced.
>
>
> On Thu, Sep 13, 2012 at 4:35 PM, Gene Helfman <genehelfman at gmail.com> wrote:
>>  Having sailed for 50+ years on boats with only one main sheet, I'll
>> admit to being totally perplexed with the port and starboard sheet
>> arrangement on the 320, especially when going upwind in anything other
>> than light air.
>>
>> My instincts tell me that hardening the upwind sheet should pull the
>> boom down and also bring it to windward (recognizing that the traveler
>> also determines boom alignment).  To do this, do you slack the downwind
> sheet?
>>  When I do this, the boom moves quickly downwind, making it even
>> harder to pull the boom and sail to the upwind side, often requiring
>> putting the sheet on the winch and cranking hard.  Is there a protocol?
>>
>> thanks,
>> gene
>> Satori #398
>> Gene Helfman, Professor Emeritus
>> Odum School of Ecology, University of Georgia PERMANENT address:
>>     498 Shoreland Dr., Lopez Is., WA 98261
>>     (360) 468-2136
>>     genehelfman at gmail.com
>>
>> "Give a man a fish and he'll eat for a day, Teach a man to fish and
>> he'll deplete the
>>       oceans."
>>
>> The Book of Bob, Ironies 24:7
>
>
>
> --
> Chris Burti
> Farmville, NC
>



-- 
Chris Burti
Farmville, NC