Rich,
You are exactly right. It's very close to a right triangle, especially when
you consider dropping a plumb from the masthead. So the math should be close
enough to work.
I'll put the correct rake in and measure the forestay pin to pin distance once
we drop the furler. However, with a guy in a chair at the masthead and no
forestay, I want to measure to confirm my calculations and not assume that the
measurement is correct.
The mast has Spartite so the position at the partners is fixed. I think the
butt may already be positioned correctly because I had 10 inches of rake before
we made the adjustments a couple months ago.
This all started when we lowered the furler drum 5-6 inches. We added an extra
toggle to the top of the forestay to make up for the tightening of the furler
turnbuckle. Not only was it not enough (a toggle adds 2 3/4 inches) but it
created some problems. It moved the top of the furler extrusion down and out
from between the spinnaker blocks that are attached to two short cranes on the
masthead. It also moved it below the exits of the headsail halyards. One of
the headsail halyards has a restrainer on it. The other does not. The halyard
without the restrainer runs so close to the forestay that the extrusion
(missing the dust cap) cuts the halyard. (Nothing like having a halyard fail
at 2 am when you're beating to windward in 24 knots and 4-6 foot seas like we
experienced in an offshore race in June.)
With a forestay of the correct length, I'll remove the toggle and restore the
previous configuration at the masthead. The top of the extrusion will then be
above the masthead internal sheaves so the halyards won't be cut by the
extrusion. I'll put on a new dust cap but they don't last forever.
As to your last point about bend. I induce about 1.5 inches of pre-bend by
tightening the forward lower shrouds and keeping the aft lowers a bit loose.
Dennis C.
Touche' 35-1 #83
Mandeville, LA
>________________________________
> From: Rich Knowles <[email protected]>
>To: "[email protected]" <[email protected]>
>Sent: Saturday, September 8, 2012 7:54 AM
>Subject: Re: Stus-List Mast rake adjustment
>
>
>Sounds about right to me, Dennis, except you really don't have a right
>triangle so the math will be slightly skewed. You might do better by drawing
>it up to scale and measuring the forestay. Why a new forestay, unless you
>don't like toggles? I assume the mast remains centered in the partners and
>the foot is allowed to reposition slightly so you won't induce bend in the
>column when you tension the rig.
>
>Rich Knowles
>LF 38
>
>
>
>
>On 2012-09-07, at 22:10, Indigo <[email protected]> wrote:
>
>
>Since there is approximately 6 ft of the mast below the partners wouldn't
>moving the foot of the mast one inch forward result in a 7 inch aft movement
>of the masthead I would think you could move the foot one inch without
>lengthening the forestay
>>
>>
>>Jonathan
>>Indigo
>>
>>On Sep 7, 2012, at 21:29, "Dennis C." <[email protected]> wrote:
>>
>>
>>Dwight,
>>>
>>>
>>>"I" is the deck to masthead measurement, i.e. the vertical side of the
>>>triangle. The forestay is the hypotenuse.
>>>
>>>
>>>
>>>I'm trying to return the rig configuration to where it was before the
>>>adjustments I made. I did have 10 inches at the gooseneck. Now just 5.
>>>Like I said, there's more to the story.
>>>
>>>
>>>Dennis C.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>>________________________________
>>>> From: dwight veinot <[email protected]>
>>>>To: [email protected]
>>>>Sent: Friday, September 7, 2012 7:07 PM
>>>>Subject: Re: Stus-List Mast rake adjustment
>>>>
>>>>
>>>>
>>>>Sorry Dennis, on reading again now I see
what you are doing…got confused when you said the new hypotenuse was
46.487, compared to what it was at 44…actually I don’t see why you
need to change the forestay at all, the head stay should have enough adjustment
in it…does it not have a turnbuckle at the bow that you could lengthen a
bit
>>>>
>>>>And another besides, why are you doing it…seems
from what I have read Touche has consistently been at or near the top…trying
for better performance or less weather helm
>>>>
>>>>Dwight Veinot
>>>>C&C 35 MKII, Alianna
>>>>Head of St. Margaret's Bay, NS
>>>>
>>>>________________________________
>>>>
>>>>From:[email protected] [mailto:[email protected]]
>>>>On Behalf Of dwight veinot
>>>>Sent: September 7, 2012 7:57 PM
>>>>To: ' Dennis C. '; [email protected]
>>>>Subject: Re: Stus-List Mast rake
adjustment
>>>>
>>>>Dennis
>>>>
>>>>I believe for your 35-1 I=44 is the
hypotenuse…you need the perpendicular measure along the mast from the
deck to the masthead
>>>>
>>>>Dwight Veinot
>>>>C&C 35 MKII, Alianna
>>>>Head of St. Margaret's Bay, NS
>>>>)
>>>>________________________________
>>>>
>>>>From:[email protected] [mailto:[email protected]]
>>>>On Behalf Of Dennis C.
>>>>Sent: September 7, 2012 7:14 PM
>>>>To: Cn Clist
>>>>Subject: Stus-List Mast rake
adjustment
>>>>
>>>>OK, check my
math and thinking on this one.
>>>>
>>>>I want to increase the rake in Touche's
mast. I made some changes in the rig a few months ago which brought the
masthead forward so the plumb from the masthead is only about 6 inches aft of
the gooseneck. It used to be 9-10 inches to get 1 degree of rake.
>>>>
>>>>The foretriangle is close to a right
triangle. I=44' and J = 14.5'. If I add the 6 inches to J (for the
plumb drop from the masthead), I get a right triangle with sides of 44.0 and
15.0 and a hypotenuse of 46.487 (the forestay).
>>>>
>>>>So, if I want to move the masthead aft
another 6 inches, I end up with a triangle of 44.0, 15.5 and 46.650. The
difference in the lengths of the hypotenuses (hypoteni?) is 0.163 or about 2
inches. By my thinking, I need a new forestay about 2 inches longer than
the existing one.
>>>>
>>>>There's more to the story than this, like
it's really 5 inches each for the plumb and rake increase and I'm removing an
extra toggle from the top but the math and method should be right.
>>>>
>>>>Am I right?
>>>>
>>>>Dennis C.
>>>>Touche' 35-1 #83
>>>>Mandeville, LA
>>>>
>>>>
>>>>
>>>>
>>>>________________________________
>>>>
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>>>>Checked by AVG - www.avg.com
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>>>>________________________________
>>>>
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>>>>
>>>>
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