JAXAshby wrote:


catenaires, and they strains imposed on the end points, is a freshman physics
discussion understood by tens of millions of 18 year old boys every year.

Times sure have change...when I was an 18-year-old boy, my interests
focused on the one-handed removal of bras. Chains came much later.


--
Not dead, in jail, or a slave? Thank a liberal!
And don't forget to pay your taxes so the rich don't have to!

just used intuitive trig

there is no such thing as intuitive trig.

How would you determine that mathematically?

Tom, it is tough math for a layman. that is why I used the geometric
explanation. lots easier math, even if it understates the forces involved.

bill, like gene, stay out of this discussion. difference if, you can ask
questions, gene can not.

neither of you is allowed to make statements until you get up to speed on the
subject. gene never will get up to speed, you might sometime next year.

"Calif Bill"
Date: 9/18/2004 10:24 PM Eastern Daylight Time
Message-id: . net


"Short Wave Sportfishing" wrote in message
.. .
On Sat, 18 Sep 2004 20:14:34 -0400, "NOYB" wrote:


"Gene Kearns" wrote in message
.. .
On 18 Sep 2004 21:15:33 GMT, (JAXAshby) wrote:

What happens during the interaction of forces on the rode would be
most fascinating.

a way to simplified look at it is to consider the chain/rode/line to
have
zero
weight pulled between two points (say 100 feet apart), then hang a 1#
weight in
the center point and check how much strain it put on the end points
when
the
weight hangs 20 feet, then 10 feet, then 5 feet, then 1 foot, then 1
inch, then
1/10th inch. Just use trig to figure the forces.

So.... we just used intuitive trig to figure out why (1) we use scope
with an anchor and (2) why we don't tie boats to the dock with chain.
Now *that* is some real science......

And your "simplified look" does not apply.... an anchor rode does not
employ both ends at the same "Y" value.... therefore assumptions of
Y=Y'=0 do not obtain and is, therefore, the root cause of your lack
of understanding in this area. There isn't *anything* *attached* to
the middle.


the forces get out of hand ********VERY******** quickly. Even worse,
is
that
the weight in the middle (or chain) has momentum as the boat rocks, so
the
"natural" position of the weight overshoots and makes for seriously
high
g-loads.


There is no weight "in the middle" (other than the weight of the rode)
.... so you put two anchors on the same rode? Odd.

Also, in jaxassby's example, the points can't always be 100' apart if the
weight is hanging further and further down each time...unless he has an
extremely elastic line and there's a large amount of stretch. I assume
that
jaxassby meant to say "using a 100' rope".

The main definition of catenary is that of a curve formed by a
perfectly flexible, uniformly dense, and inextensible cable suspended
from its endpoints. It would look a lot like hyperbolic cosine if you
graphed it out. Which, now that I think about it, wouldn't look a lot
like an anchor rode as much as a tow line.

I'm more curious about strain towards the middle of the curve. That
would be fairly easy to measure at either end, but if you have two
opposing forces of two different weights, say as in a barge tow, the
center strain would constantly move towards one or the other depending
on the weights.

How would you determine that mathematically?

Later,

Tom

The end points are not at the same elevation.

JAXAshby wrote:
bill, like gene, stay out of this discussion. difference if, you can ask
questions, gene can not.

neither of you is allowed to make statements until you get up to speed on the
subject. gene never will get up to speed, you might sometime next year.


Ker-ripes, Jaxass. You should at all costs avoid the use of the word
"speed" or its variation "speedo."


--
Not dead, in jail, or a slave? Thank a liberal!
And don't forget to pay your taxes so the rich don't have to!

It only has to have a
90º tangent at some point along the curve.

not sure what you are trying to say there, for no curve has a 90* tangent.

yo-yo, the shock absorbing capability is dependent on how much sag is in the
(inelastic) chain. lots of sag, lots of shock absorbtion. less sag, a hell of
a lot less absorbtion. little sag, almost no shock absorbtion.

"NOYB"
Date: 9/18/2004 10:11 PM Eastern Daylight Time
Message-id:


"JAXAshby" wrote in message
...
genie, shut up.

Subject: Why need anchor chain?
From: Gene Kearns
Date: 9/18/2004 7:46 PM Eastern Daylight Time
Message-id:

On 18 Sep 2004 21:15:33 GMT, (JAXAshby) wrote:

What happens during the interaction of forces on the rode would be
most fascinating.

a way to simplified look at it is to consider the chain/rode/line to
have
zero
weight pulled between two points (say 100 feet apart), then hang a 1#
weight
in
the center point and check how much strain it put on the end points when
the
weight hangs 20 feet, then 10 feet, then 5 feet, then 1 foot, then 1
inch,
then
1/10th inch. Just use trig to figure the forces.

So.... we just used intuitive trig to figure out why (1) we use scope
with an anchor and (2) why we don't tie boats to the dock with chain.
Now *that* is some real science......

And your "simplified look" does not apply.... an anchor rode does not
employ both ends at the same "Y" value.... therefore assumptions of
Y=Y'=0 do not obtain and is, therefore, the root cause of your lack
of understanding in this area. There isn't *anything* *attached* to
the middle.


the forces get out of hand ********VERY******** quickly. Even worse, is
that
the weight in the middle (or chain) has momentum as the boat rocks, so
the
"natural" position of the weight overshoots and makes for seriously high
g-loads.


There is no weight "in the middle" (other than the weight of the rode)
.... so you put two anchors on the same rode? Odd.

Using that concept, most people use kellets and think it is a good and
useful idea.



http://www.johnsboatstuff.com/Articles/anchor.htm

" Having a lot of sag in the rode reduces shock loads "

Isn't that what started this whole argument? Anchor chain introduces sag in
the rode. Sag in the rode reduces shock loads. So I guess I was right when
I said that anchor chain acts as a shock absorber, eh jaxie?

no.

Where is the catenary on a yo-yo hanging from a finger? It is a line
between 2 points.

"JAXAshby" wrote in message
...
clown, check the meaning of the word.

Gene Kearns
Date: 9/18/2004 7:22 PM Eastern Daylight Time
Message-id:

On 18 Sep 2004 20:49:57 GMT, (JAXAshby) wrote:

spell it any way you want, you still do not have any idea what it is.

yo-yo, a string strung between two points has, and always has, a
catenary.
go
look it up.

And a yo-yo is about the depth of your comprehension, here....

--



Grady-White Gulfstream, out of Southport, NC.

http://myworkshop.idleplay.net/cavern/
Homepage
http://www.southharbourvillageinn.com/directions.asp Where
Southport,NC
is located.
http://www.thebayguide.com/rec.boats
Rec.boats
at Lee Yeaton's Bayguide

hoary, when you were 18 you had no career plans greater than becoming the night
shift manager at the gas station.

btw, hoary, a whole lot of 18 year old boys are well past learning one handed
bra removal, and are practising panty removal using the toes.


catenaires, and they strains imposed on the end points, is a freshman
physics
discussion understood by tens of millions of 18 year old boys every year.

Times sure have change...when I was an 18-year-old boy, my interests
focused on the one-handed removal of bras. Chains came much later.


--
Not dead, in jail, or a slave? Thank a liberal!
And don't forget to pay your taxes so the rich don't have to!

No kidding. With no sag, the anchor pulls loose...something even *you*
agreed with. Since anybody with a boat can tell you that anchors actually
work and don't pull loose most of the time, it stands to reason that there
must be a lot of sag in the line under most conditions. With me so far?

If there's a lot of sag in the line, then the sag provides absorption of
shock loads...just as I stated.









"JAXAshby" wrote in message
...
yo-yo, the shock absorbing capability is dependent on how much sag is in
the
(inelastic) chain. lots of sag, lots of shock absorbtion. less sag, a
hell of
a lot less absorbtion. little sag, almost no shock absorbtion.

"NOYB"
Date: 9/18/2004 10:11 PM Eastern Daylight Time
Message-id:


"JAXAshby" wrote in message
...
genie, shut up.

Subject: Why need anchor chain?
From: Gene Kearns
Date: 9/18/2004 7:46 PM Eastern Daylight Time
Message-id:

On 18 Sep 2004 21:15:33 GMT, (JAXAshby) wrote:

What happens during the interaction of forces on the rode would be
most fascinating.

a way to simplified look at it is to consider the chain/rode/line to
have
zero
weight pulled between two points (say 100 feet apart), then hang a 1#
weight
in
the center point and check how much strain it put on the end points
when
the
weight hangs 20 feet, then 10 feet, then 5 feet, then 1 foot, then 1
inch,
then
1/10th inch. Just use trig to figure the forces.

So.... we just used intuitive trig to figure out why (1) we use scope
with an anchor and (2) why we don't tie boats to the dock with chain.
Now *that* is some real science......

And your "simplified look" does not apply.... an anchor rode does not
employ both ends at the same "Y" value.... therefore assumptions of
Y=Y'=0 do not obtain and is, therefore, the root cause of your lack
of understanding in this area. There isn't *anything* *attached* to
the middle.


the forces get out of hand ********VERY******** quickly. Even worse,
is
that
the weight in the middle (or chain) has momentum as the boat rocks,
so
the
"natural" position of the weight overshoots and makes for seriously
high
g-loads.


There is no weight "in the middle" (other than the weight of the rode)
.... so you put two anchors on the same rode? Odd.

Using that concept, most people use kellets and think it is a good and
useful idea.



http://www.johnsboatstuff.com/Articles/anchor.htm

" Having a lot of sag in the rode reduces shock loads "

Isn't that what started this whole argument? Anchor chain introduces sag
in
the rode. Sag in the rode reduces shock loads. So I guess I was right
when
I said that anchor chain acts as a shock absorber, eh jaxie?