Thread: Cunningham
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Marty Browne
 
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Default Cunningham

Real boats-schmeel boats. a fixed gooseneck properly attached to the
mast is mechanically stronger than the sliding gooseneck on the track.
And there is a weight savings by not needing all the heavy gooseneck
track and heavy gooseneck. Having a fixed gooseneck, means that you
don't have to worry about the forward end of of the boom damaging heads,
fingers or other body parts. A second benefit derived from the fixed
gooseneck rig is that the modern "kicker boomvang" can be used rather
than a preventer vang lead from the rail up to the boom.

If you have older style rig with sliding gooseneck, I would seek the
opinion of a skilled spar-maker/worker before discarding the sliding
gooseneck rig. Some masts and booms will need additional re-enforcement
before installing that fixed gooseneck.

About the right amount of cunningham tension.------ On most of the boats
that I race on, the main halyard controls the top 2/3 of the luff and
sail shape. The Cunningham controls the bottom 2/3 of the luff and sail
shape. I didn't make a typo. Even though it doesn't make sense, that is
exactly what is happening on most boats that have a good racing main.
The halyard affects both the luff and the leach; it changes the draft
location and effect a slight flattening or fullness at the top of the
sail. The cunningham effects the bottom luff tension and bottom section
of the sail. It doesn't have a major effect on the foot shape or outhaul
tension. How much cunningham or main halyard to use or not use is part
of the art of the sailor.

I own a Sonar. Our fractional rig is very different from the old
masthead IOR & IMS rigs that I used to race every weekend. I also race
an AERODYNE 38. It has a huge, full-battened main with a tremendous
roach and a 105% jib. we are learning that the Etchells and Sonars that
some of the crew race are more closely related to that 38' offshore boat
than the masthead IOR and IMS boats the owner used to race. Makes for
interesting learning experiences.


If you have a "cruisier" main, you will see less effect as you try to
tweak the various controls. The sail has been built to have a wider
range of acceptable tensions. it will be less responsive to minute
changes in outhaul and main luff(halyard & cunningham) tensions. But it
will be easier to trim and make fast.
good luck and have fun.



Jack Dale wrote:
On Thu, 17 Jul 2003 18:42:40 -0400, "Simple Simon"
wrote:


Real boats have a sliding gooseneck so one can raise the
mainsail to the top black line and allow the boom to slide
up for ease of uphauling without a winch. Once the halyard
is made fast, tension along the luff can easily be made by
drawing down on the boom using the mainsheet so the
downhaul can be cleated off.

Cunningham cringles and tackle are something that are
totally unnecessary on any boat with a sliding gooseneck.
This is but another advantage of a boat that is set up to
cruise instead of to race. Cunningham gear is just a way
to get around the rules of racing and as such should be
used only on racing yachts.



Real "little" boats use a sliding goosenecks and downhauls, real big
boats use riveted goosenecks and cunninghams. When I race a San Juan
21 we use both a downhaul for rough sail shape and a cunningham to
fine tune. The larger boats I sail have riveted goosenecks and
cunninghams.



"Gerard Weatherby" wrote in message ...

Cat's Meow is sailng with a new mainsail this year. The sail has a separate
grommet for a downhaul (Cunningham) in additional to the tack. Given I'm
working with a single winch on the mast, does it make more sense to use the
winch for the main halyard and tighten the downhaul by hand, or raise the main
by hand and use the winch for the downhaul? I tried raising the main by hand
yesterday in a relatively* brisk wind, ~15 knots, and it didn't seem like the
main got raised enough.

*Relative to the usual Long Island Sound light air.

S/V Cat's Meow
http://www.catsmeow.org



Raise your main (with a winch if necessary) until you get a loose fold
along the luff. Use some sort of a purchase system (a block and
tackle with a cam cleat) for the cunningham to adjust the position of
the draft of your main. Attach a hook to the cunningham cringle and
the other end to the base of your mast. Harden the cunningham to
move the draft forward, ease the cunningham to move the draft aft.

Briggs is probably doing a rollover.

Jack