That's why triangular sections have the greatest rigidty for
their cross section area, and square sections are more rigid than oval
or round.


Nav wrote:
I think you may be confusing a truss with a section.

Nope.

... For bending in
plane

In what plane?

... the most rigid section per unit weight

Did I say "per unit weight"? No I said cross section area.

... is close to a T
section with the top under compression and the bulb (or smaller bottom
plate) at the bottom in tension.

You're describing an asymmetric I-beam.

Now, think for a moment... have you seen any sailboat booms shaped like
I-beams?

No, you haven't. But if you've looked at pictures of fancy hi-dollar
racing yachts, you have seen triangular section booms.

Why is that, Navvie?


Maybe you better go call up Bruce Farr and tell him he's been getting it
wrong. He'll probably offer you a job.

DSK

You may be confused. Perhaps you would like to re-read your earlier
post? I'll highlight it for you:


DSK wrote:
That's why triangular sections have the greatest rigidty for
their cross section area, and square sections are more rigid than
oval or round.

You did say most rigid didn't you? I'd say that rigid means best able to
resist bending -but perhaps you have some other use of the term? It's
strange but engineering texts say that the section that best resists
bending is an I or T section. But Doug is always right so we must all be
wrong!

Now, since you've neatly drawn and posted a diagram why haven't you
actually shown us where your cosine is or what the forces on the boom
are. I gave you a solution but you've not explained why it's wrong.
C'mon share your engineering expertise!

I'd say this is a smokscreen and you are trying to wriggle off the hook.

Cheers

DSK wrote:

So, I take that you've folded up a boom trying to lift something? Can
we assume that you learned nothing from it, other than "don't"?


Nav wrote:

Such vivid imagination.


Well, I have seen booms supported by rigid vangs that didn't fold up, so
obviously it can be done... if you do it right.

You think it can't be done, why? Conclusion: you did it wrong, and
decided it was impossible.


Yes a very vivid imagination. Dougs world -LOL


Funny you should say that, since you show no comprehension of how to
read the diagram, yet you pass judgement on my competence. The
resolution of forces is not obvious but it's also not rocket science.

If OTOH you *do* have some clue what you're talking about, tell us what
the mysterious symbol next to the mast represents.


Your statement makes no sense as you need to least show why my
calculation is wrong. After all I did solve the problem for the second
case for you -so either I can resolve forces and am correct or I cannot
and my answer is wrong! which is it? It would seem that you disagree
with my freshman solution so where's yours? So far you've only blustered
and obfuscated so I can't wait to see where the cosine in your diagram
gives the compression on the boom!

By the way, use of symbols does not mean that you understand them
-especially if _you_ put them in the wrong place.

Cheers

Try to keep up.
Scout

"Nav" wrote in message
...
I'm wondering what you are talking about.

Cheers

Scout wrote:

And I'm wondering what the formulation time has to do with how long
you've
been waiting to work it into a conversation.
Scout

"Nav" wrote in message
...

I wonder what "formuilating a problem" has to do with typing?

Cheers



Capt. Mooron wrote:

Heh... who cares... she gets paid.. she types.

CM

"Scout" wrote in message
...
| I'll bet she just loves being forced into asa ****ing contests.
| Scout
|
| "Capt. Mooron" wrote in message
| ...
| He uses a secretary ... she types about 120 wpm.
|
| CM
|
|
|
| "Scout" wrote in message
| ...
| | I don't believe you can type that fast.
| | Scout
|
|
|
|

"Capt. Mooron" wrote

Quit toying with the damn boom.... look think of it this way... how
many
lifting devices utilize a support located under the boom at less
than 25% of
the boom length? NONE!

Wrong, kanook.
Have you never seen an engine crane?
A bascule type draw bridge?
Any hydraulic crane with the boom out?
An excavator?

need more?

Scotty

OK Doug,

Since you made the statement; "Except for being used for a spare Back
Stay the Rigid Vang can do everything that a topping lift can do."

It's turned into a yes it can, no it can't.
So, let's change it to; A Topping Lift can be used as a Hoisting Device
even without the "BOOM".

Now, can the solid vang do that without modification?

Ole Thom

I extend my topping lift (quick disconnect fitting) and send it forward as
an assist line when stepping my mast. It's useless until I lift to about
25-30 degrees, but that's about where I'm stepping on the coach roof, and
can really appreciate someone holding steady at the bow.
On the other hand, I have no vang but see the need, especially in the case
of accidental gybes in strong breezes, in which cases I've had my boom
raised high enough to snag and hang up on my back stay.
Scout

"Thom Stewart" wrote in message
...
Bart,

I know that topping lift can be a PITA but it still has a lot of
advantages over the rigid vang. Just to mention a few;

A spare and ready back stay

A man overboard hoist

An end reinforcement of the boom when you want to use it as a crane
(Dingy recovery)

Ole Thom
P/S I've used to tail as a temporary sheet while clearing an over-ride
on the main sheet wench

Scout,

You, my friend, Need the topping lift. The way you sail and the boat you
sail you should be considering a "Cruising Vang" set-up and be-damned to
the Std Vang.

If you aren't aware of what I'm talking about, I'll explain;

Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Set a block on each Toe-rail directly under the Boom's position when the
Boom is fully let out. If you have a metal toe rail. If not you can use
the hand rail stanchion base.
( Close enough is good enough) Run a lite line from the Boom thru the
block and back to the cockpit. If you don't have a cleat, use the stern
mooring cleats. I hook my lines to the Boom with loops to a cleat on the
Boom at about the Vang location. That's it!!

When on a reach, I can pull the Boom down with the off side sheet winch.
When running free, I use it as a preventer to stop the Accidental Jibe.
I use it also as a Boom brake while Jibing.

Try it. A lot cheaper than a vang and you get a preventer you can set
from the cockpit.

Let Doug have his solid vang

Ole Thom

"Scott Vernon" wrote in message
...
|
| "Capt. Mooron" wrote
|
| Quit toying with the damn boom.... look think of it this way... how
| many
| lifting devices utilize a support located under the boom at less
| than 25% of
| the boom length? NONE!
|
| Wrong, kanook.
| Have you never seen an engine crane?

Is the brace located at 25% of the arm's length? I believe the hydraulic ram
is located at 50% or more of the arm length.

| A bascule type draw bridge?

It's only lifting the bridge [boom] .. and again not at only 25% of the span

| Any hydraulic crane with the boom out?

Not at less than 25% of the boom.... extend the boom and the capacities
decrease exponentially.

| An excavator?

Double Hydraulic rams to the main boom at 50% distance or better to the
elbow and a third along the top of the stick to control breakout and curl.
Limits imposed are with bucket size and hydraulic capacity.

|
| need more?

Sure... the examples you provided so far hasn't done anything to convince me
that the capacity of a lifting device secured to a location less than 25% of
the span of the boom can lift as much as one located at the end of the boom.

Make note I never claimed a device secured to the bottom couldn't lift a
weight... only that the location of the vang in this instance is far too
short to accommodate the capacity of a topping lift.

Look Scotty... if you place a pair of hydraulic rams to the end of the
boom.... or a distance greater than 50 % of the span.. then the issue
becomes moot. The specific point I'm making is that the rigid vang is badly
situated to handle loads delivered to the end of the boom.

I'll stand by that claim...

CM

"Capt. Mooron" wrote |
| Wrong, kanook.
| Have you never seen an engine crane?

Is the brace located at 25% of the arm's length? I believe
the hydraulic ram
is located at 50% or more of the arm length.

So you've never seen one. It is at 25% and less when the
boom is extended out. Here's a pic of one my little Canuck
friend.
http://www.jcwhitney.com/autoparts/P...lay/s-10101/p-
1498/c-10101


| A bascule type draw bridge?

It's only lifting the bridge [boom] .. and again not at
only 25% of the span


Only the bridge? You have any idea what a bridge weighss?
And the gear is at about 5%, I'd say.



| Any hydraulic crane with the boom out?

Not at less than 25% of the boom.... extend the boom and
the capacities
decrease exponentially.

Here's a pic of a Grove Crane, very popular in this area.
See where the hyd cylinders are connected to the boom? I'd
guess that's about 10%. What do you say?
http://www.marcelequipment.com/Misc/grovert58c.htm




| An excavator?

Double Hydraulic rams to the main boom at 50% distance or
better to the
elbow and a third along the top of the stick to control
breakout and curl.
Limits imposed are with bucket size and hydraulic
capacity.


Guess again office worker. Here's another pic for you.
Can you say 10%?

http://usediron.point2.com/Xhtml/Equ...ails/P2/Excava
tor-Long-Reach/CATERPILLAR/320C/153870/ByManufacturer.html


| need more?

Sure... the examples you provided so far hasn't done
anything to convince me
that the capacity of a lifting device secured to a
location less than 25% of
the span of the boom can lift as much as one located at
the end of the boom.

How about a diving board?

look at the pretty pictures again. Study them, measure them.
Take a few days, then get back to me.

Scotty

Thanks for the input Thom,
I'll have to use the stanchion base, but it's easy enough. I will give it a
try.
Scout

"Thom Stewart" wrote in message
...
Scout,

You, my friend, Need the topping lift. The way you sail and the boat you
sail you should be considering a "Cruising Vang" set-up and be-damned to
the Std Vang.

If you aren't aware of what I'm talking about, I'll explain;

Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Set a block on each Toe-rail directly under the Boom's position when the
Boom is fully let out. If you have a metal toe rail. If not you can use
the hand rail stanchion base.
( Close enough is good enough) Run a lite line from the Boom thru the
block and back to the cockpit. If you don't have a cleat, use the stern
mooring cleats. I hook my lines to the Boom with loops to a cleat on the
Boom at about the Vang location. That's it!!

When on a reach, I can pull the Boom down with the off side sheet winch.
When running free, I use it as a preventer to stop the Accidental Jibe.
I use it also as a Boom brake while Jibing.

Try it. A lot cheaper than a vang and you get a preventer you can set
from the cockpit.

Let Doug have his solid vang

Ole Thom

"Scott Vernon" wrote in message

| So you've never seen one. It is at 25% and less when the
| boom is extended out. Here's a pic of one my little Canuck
| friend.
| http://www.jcwhitney.com/autoparts/P...lay/s-10101/p-
| 1498/c-10101

Sorry.. got an error message on that link

|
|
| | A bascule type draw bridge?
|
| It's only lifting the bridge [boom] .. and again not at
| only 25% of the span
|
|
| Only the bridge? You have any idea what a bridge weighss?
| And the gear is at about 5%, I'd say.

Lifting the bridge / Lifting the boom - Geared rams / Solid Vang ... hang a
boat off the end of the ramp and see if it still lifts.


|
|
|
| | Any hydraulic crane with the boom out?
|
| Not at less than 25% of the boom.... extend the boom and
| the capacities
| decrease exponentially.
|
| Here's a pic of a Grove Crane, very popular in this area.
| See where the hyd cylinders are connected to the boom? I'd
| guess that's about 10%. What do you say?
| http://www.marcelequipment.com/Misc/grovert58c.htm

That rig will lift only it's own boom when the boom is fully extended in a
horizontal position Scotty. The max. capacity is of this model at 18 tons is
reached only with the stick up fully [vertical] and the load as close to the
rams as possible. This would base the weight closer to the rams.[and
counterweights]
Now anyone who has worked around such equipment would understand that the
crane's capacitiy decreases exponentially the further down the boom is
lowered. That's because the distance between the rams and the load point is
extended. At the point the rams reach less than 25% of the distance to the
load capacity is reduced to less than a 1/4 of it's maximum rated capacity.

BTW - I operated both Crane & Excavators many years ago.

Just for your benefit since it seems you have not bothered to read my
initial reply.. I'll just repost it below to refresh your memory.

"Look Scotty... if you place a pair of hydraulic rams to the end of the
boom.... or a distance greater than 50 % of the span.. then the issue
becomes moot. The specific point I'm making is that the rigid vang is badly
situated to handle loads delivered to the end of the boom.

I'll stand by that claim..."




| | An excavator?
|
| Double Hydraulic rams to the main boom at 50% distance or
| better to the
| elbow and a third along the top of the stick to control
| breakout and curl.
| Limits imposed are with bucket size and hydraulic
| capacity.
|
|
| Guess again office worker. Here's another pic for you.
| Can you say 10%?
|
| http://usediron.point2.com/Xhtml/Equ...ails/P2/Excava
| tor-Long-Reach/CATERPILLAR/320C/153870/ByManufacturer.html

First off I'm in the field not the office.
Secondly you'd better do some research on why that long stick has such a
small bucket.
The sixty foot long stick I worked with this spring could not lift anywhere
near it's same sized standard boom excavator. Long Sticks are generally used
for dredging work.. light loads, long reach. It has reduced break-out
abilities. Probably because the load is further away from the rams!!....
DUH!

Maybe you should google for serious excavators... drag lines used to do
really heavy lifting...


| | need more?
|
| Sure... the examples you provided so far hasn't done
| anything to convince me
| that the capacity of a lifting device secured to a
| location less than 25% of
| the span of the boom can lift as much as one located at
| the end of the boom.
|
| How about a diving board?

Dopey!! ... put Bob at the end of a diving board and see if you can lift
it from below close to the base? Now put a block and tackle [1ton] to the
end of the diving board and you should be able to lift it level.. even with
Bob on it.

|
| look at the pretty pictures again. Study them, measure them.
| Take a few days, then get back to me.

Yes Jax

CM

Yr right Thom, a few sharp turns on the Del (just a bit further up the River
does a 90 deg turn in about 2500 feet). The wind gets swirling too, due to
all the obstructions (e.g., a mountainous landfill) so it seems to be coming
from all directions. The current gets strong too, and when passing under the
two bridges, especially the PA turnpike bridge, it feels like the sailboat
equivalent of "shooting the rapids." I've never been able to sail upriver
through these points without the tide's help (or motor-sailing).
Scout

"Thom Stewart" wrote
[snip]
Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Good idea, but a word of caution. Most production stanchion bases I
have seen do not have enough meat in them to handle the shock loads
associated with a preventer. The little loops of steel do not have
enough weldment on the socket or base.


On Sat, 28 Aug 2004 14:22:31 -0700, (Thom Stewart)
wrote:

Scout,

You, my friend, Need the topping lift. The way you sail and the boat you
sail you should be considering a "Cruising Vang" set-up and be-damned to
the Std Vang.

If you aren't aware of what I'm talking about, I'll explain;

Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Set a block on each Toe-rail directly under the Boom's position when the
Boom is fully let out. If you have a metal toe rail. If not you can use
the hand rail stanchion base.
( Close enough is good enough) Run a lite line from the Boom thru the
block and back to the cockpit. If you don't have a cleat, use the stern
mooring cleats. I hook my lines to the Boom with loops to a cleat on the
Boom at about the Vang location. That's it!!

When on a reach, I can pull the Boom down with the off side sheet winch.
When running free, I use it as a preventer to stop the Accidental Jibe.
I use it also as a Boom brake while Jibing.

Try it. A lot cheaper than a vang and you get a preventer you can set
from the cockpit.

Let Doug have his solid vang

Ole Thom

We take ours straight to the rail...tying off to the stanchion base also
weakens the seal and you end up with leaks from all the pull there....

"Marc" wrote in message
...
Good idea, but a word of caution. Most production stanchion bases I
have seen do not have enough meat in them to handle the shock loads
associated with a preventer. The little loops of steel do not have
enough weldment on the socket or base.


On Sat, 28 Aug 2004 14:22:31 -0700, (Thom Stewart)
wrote:

Scout,

You, my friend, Need the topping lift. The way you sail and the boat you
sail you should be considering a "Cruising Vang" set-up and be-damned to
the Std Vang.

If you aren't aware of what I'm talking about, I'll explain;

Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Set a block on each Toe-rail directly under the Boom's position when the
Boom is fully let out. If you have a metal toe rail. If not you can use
the hand rail stanchion base.
( Close enough is good enough) Run a lite line from the Boom thru the
block and back to the cockpit. If you don't have a cleat, use the stern
mooring cleats. I hook my lines to the Boom with loops to a cleat on the
Boom at about the Vang location. That's it!!

When on a reach, I can pull the Boom down with the off side sheet winch.
When running free, I use it as a preventer to stop the Accidental Jibe.
I use it also as a Boom brake while Jibing.

Try it. A lot cheaper than a vang and you get a preventer you can set
from the cockpit.

Let Doug have his solid vang

Ole Thom

I've learned a lot with this boat. My next boat will have more bells and
whistles, and be more seaworthy. I've also worried about the stays being
ripped out by their roots, particularly when I've taken the boat outside,
through the inlet South of Long Beach Island, NJ. I've been tossed around a
good bit and wondered how much stress/shock they could handle.
Scout

"Marc" wrote in message
...
Good idea, but a word of caution. Most production stanchion bases I
have seen do not have enough meat in them to handle the shock loads
associated with a preventer. The little loops of steel do not have
enough weldment on the socket or base.


On Sat, 28 Aug 2004 14:22:31 -0700, (Thom Stewart)
wrote:

Scout,

You, my friend, Need the topping lift. The way you sail and the boat you
sail you should be considering a "Cruising Vang" set-up and be-damned to
the Std Vang.

If you aren't aware of what I'm talking about, I'll explain;

Sailing on the Delaware River
(especially on that bend at St Mary's Hall)
You need a Vang that is also a "Preventer" It is cheaper and more
effective on your size boat.

Set a block on each Toe-rail directly under the Boom's position when the
Boom is fully let out. If you have a metal toe rail. If not you can use
the hand rail stanchion base.
( Close enough is good enough) Run a lite line from the Boom thru the
block and back to the cockpit. If you don't have a cleat, use the stern
mooring cleats. I hook my lines to the Boom with loops to a cleat on the
Boom at about the Vang location. That's it!!

When on a reach, I can pull the Boom down with the off side sheet winch.
When running free, I use it as a preventer to stop the Accidental Jibe.
I use it also as a Boom brake while Jibing.

Try it. A lot cheaper than a vang and you get a preventer you can set
from the cockpit.

Let Doug have his solid vang

Ole Thom

"Capt. Mooron" wrote

| So you've never seen one. It is at 25% and less when the
| boom is extended out. Here's a pic of one my little Canuck
| friend.
| http://www.jcwhitney.com/autoparts/P...lay/s-10101/p-
| 1498/c-10101

Sorry.. got an error message on that link


can't you cut & paste?

http://www.jcwhitney.com/autoparts/P...1/p-1498/c-101
01

look at the first one. Closely.



|
| Only the bridge? You have any idea what a bridge weighss?
| And the gear is at about 5%, I'd say.

Lifting the bridge / Lifting the boom - Geared rams / Solid Vang ...
hang a
boat off the end of the ramp and see if it still lifts.


Yes, it will.




Maybe you should google for serious excavators... drag lines used to
do
really heavy lifting...


Serious drag lines/cranes (stick cranes) use a 'topping lift', so to
speak.


| need more?
|
| Sure... the examples you provided so far hasn't done
| anything to convince me
| that the capacity of a lifting device secured to a
| location less than 25% of
| the span of the boom can lift as much as one located at
| the end of the boom.


Well, duh, any 7th grade student knows that.

You wrote;
"Capt. Mooron" wrote

how many
lifting devices utilize a support located under the boom at less
than 25% of
the boom length? NONE!


And I gave you some examples to prove your statement false.




| How about a diving board?

Dopey!! ... put Bob at the end of a diving board and

it would break.



Now put a block and tackle [1ton] to the
end of the diving board and you should be able to lift it level..
even with
Bob on it.

better use a 5 ton.


Is there any body here who is smart & good looking?

Yes ,Jax

CM


Oiy!


Scotty

Scott,

You are going "a bit afield" on your comparison. Would you use a Grove
cherry picker arm for a boom on a sail? Would be a bit of overkill,
wouldn't it? Same for half a draw bridge. I sure as hell wouldn't want
to sail Wing-on-Wing anything heavier than my round Alum. Boom.

Imagine getting hit in the head with the weight of a Grove in an
accidental jibe?:^)

Ole Thom

Yes, Thom , I know. I'm just trying to knock the arrogant Mooron down
a notch by pointing out the falsehood of his statement.

Scotty


"Thom Stewart" wrote in message
...
Scott,

You are going "a bit afield" on your comparison. Would you use a
Grove
cherry picker arm for a boom on a sail? Would be a bit of overkill,
wouldn't it? Same for half a draw bridge. I sure as hell wouldn't
want
to sail Wing-on-Wing anything heavier than my round Alum. Boom.

Imagine getting hit in the head with the weight of a Grove in an
accidental jibe?:^)

Ole Thom

Yes, Thom , I know. I'm just trying to knock the arrogant Mooron down
a notch by pointing out the falsehood of his statement.


Newsflash!!! Mooron owns a real sailing boat, unlike Scotty Potti's Paceresque,
Yugo Marine, K-Mart Keeled, krappy & sad Siedlemann.
But then he's secure enough to ignore this post. Whew!!!!! Lucky for me!

RB

"Scott Vernon" wrote in message
...
| Yes, Thom , I know. I'm just trying to knock the arrogant Mooron down
| a notch by pointing out the falsehood of his statement.

I never considered arrogance a character flaw Scotty! :-)

But like you said:
"Serious drag lines/cranes (stick cranes) use a 'topping lift', so to
speak"

Better supply some more examples.... or at least start calling me
anti-semantic or something!

I'm starting to feel ignored around here already!


CM

"Scott Vernon" wrote in message
...
| "Capt. Mooron" wrote
|| | Sure... the examples you provided so far hasn't done
| | anything to convince me
| | that the capacity of a lifting device secured to a
| | location less than 25% of
| | the span of the boom can lift as much as one located at
| | the end of the boom.
|
|
| Well, duh, any 7th grade student knows that.

Tell Doug.... not me!

CM

Capt. Mooron wrote:
"Scott Vernon" wrote in message
...
| "Capt. Mooron" wrote
|| | Sure... the examples you provided so far hasn't done
| | anything to convince me
| | that the capacity of a lifting device secured to a
| | location less than 25% of
| | the span of the boom can lift as much as one located at
| | the end of the boom.
|
|
| Well, duh, any 7th grade student knows that.

Tell Doug.... not me!


Don't do the math or he'll run away!

Cheers

Although I've seen many superyacht hydraulic vangs I don't recall one
being rigged as a crane. They seem to be designed so that if hydraulic
power is lost the boom is in the correct position for the sail to furl
so that there would seem little need to have two sided supply to the
piston and extra seals. They launch large RHIBS etc. with dedicated
folding cranes but not the boom.

Cheers



Capt. Mooron wrote:
"Scott Vernon" wrote in message

| So you've never seen one. It is at 25% and less when the
| boom is extended out. Here's a pic of one my little Canuck
| friend.
| http://www.jcwhitney.com/autoparts/P...lay/s-10101/p-
| 1498/c-10101

Sorry.. got an error message on that link

|
|
| | A bascule type draw bridge?
|
| It's only lifting the bridge [boom] .. and again not at
| only 25% of the span
|
|
| Only the bridge? You have any idea what a bridge weighss?
| And the gear is at about 5%, I'd say.

Lifting the bridge / Lifting the boom - Geared rams / Solid Vang ... hang a
boat off the end of the ramp and see if it still lifts.


|
|
|
| | Any hydraulic crane with the boom out?
|
| Not at less than 25% of the boom.... extend the boom and
| the capacities
| decrease exponentially.
|
| Here's a pic of a Grove Crane, very popular in this area.
| See where the hyd cylinders are connected to the boom? I'd
| guess that's about 10%. What do you say?
| http://www.marcelequipment.com/Misc/grovert58c.htm

That rig will lift only it's own boom when the boom is fully extended in a
horizontal position Scotty. The max. capacity is of this model at 18 tons is
reached only with the stick up fully [vertical] and the load as close to the
rams as possible. This would base the weight closer to the rams.[and
counterweights]
Now anyone who has worked around such equipment would understand that the
crane's capacitiy decreases exponentially the further down the boom is
lowered. That's because the distance between the rams and the load point is
extended. At the point the rams reach less than 25% of the distance to the
load capacity is reduced to less than a 1/4 of it's maximum rated capacity.

BTW - I operated both Crane & Excavators many years ago.

Just for your benefit since it seems you have not bothered to read my
initial reply.. I'll just repost it below to refresh your memory.

"Look Scotty... if you place a pair of hydraulic rams to the end of the
boom.... or a distance greater than 50 % of the span.. then the issue
becomes moot. The specific point I'm making is that the rigid vang is badly
situated to handle loads delivered to the end of the boom.

I'll stand by that claim..."




| | An excavator?
|
| Double Hydraulic rams to the main boom at 50% distance or
| better to the
| elbow and a third along the top of the stick to control
| breakout and curl.
| Limits imposed are with bucket size and hydraulic
| capacity.
|
|
| Guess again office worker. Here's another pic for you.
| Can you say 10%?
|
| http://usediron.point2.com/Xhtml/Equ...ails/P2/Excava
| tor-Long-Reach/CATERPILLAR/320C/153870/ByManufacturer.html

First off I'm in the field not the office.
Secondly you'd better do some research on why that long stick has such a
small bucket.
The sixty foot long stick I worked with this spring could not lift anywhere
near it's same sized standard boom excavator. Long Sticks are generally used
for dredging work.. light loads, long reach. It has reduced break-out
abilities. Probably because the load is further away from the rams!!....
DUH!

Maybe you should google for serious excavators... drag lines used to do
really heavy lifting...


| | need more?
|
| Sure... the examples you provided so far hasn't done
| anything to convince me
| that the capacity of a lifting device secured to a
| location less than 25% of
| the span of the boom can lift as much as one located at
| the end of the boom.
|
| How about a diving board?

Dopey!! ... put Bob at the end of a diving board and see if you can lift
it from below close to the base? Now put a block and tackle [1ton] to the
end of the diving board and you should be able to lift it level.. even with
Bob on it.

|
| look at the pretty pictures again. Study them, measure them.
| Take a few days, then get back to me.

Yes Jax

CM

Nav wrote:
Your statement makes no sense

I believe that it does not make sense to *you*.

Try asking for some help from down the hall...


DSK

Thom Stewart wrote:
OK Doug,

Since you made the statement; "Except for being used for a spare Back
Stay the Rigid Vang can do everything that a topping lift can do."

It's turned into a yes it can, no it can't.

Well, in my defense I plead that engineering is not a matter for
democratic vote.

So, let's change it to; A Topping Lift can be used as a Hoisting Device
even without the "BOOM".

Now, can the solid vang do that without modification?


My hat's off to you, Thom.

Regards
Doug King

| Wrong, kanook.
| Have you never seen an engine crane?

Capt. Mooron wrote:
Is the brace located at 25% of the arm's length? I believe the hydraulic ram
is located at 50% or more of the arm length.

Some are, some aren't.

It's pretty clear that you're not interested in facts, you're interested
in arguing.

I'm checking out of this thread.

DSK

"Capt. Mooron" wrote

But like you said:
"Serious drag lines/cranes (stick cranes) use a 'topping lift', so
to
speak"

Better supply some more examples....

Wha? Mr. 'I work in the field' has never seen a big stick crane.
Look for a Manatowoc 4200 crawler crane.

SV

Did Doug claim otherwise? I didn't see it.

Scotty


"Capt. Mooron" wrote in message
...

"Scott Vernon" wrote in message
...
| "Capt. Mooron" wrote
|| | Sure... the examples you provided so far hasn't done
| | anything to convince me
| | that the capacity of a lifting device secured to a
| | location less than 25% of
| | the span of the boom can lift as much as one located at
| | the end of the boom.
|
|
| Well, duh, any 7th grade student knows that.

Tell Doug.... not me!

CM

"DSK" wrote in message
. ..
| Wrong, kanook.
| Have you never seen an engine crane?

Capt. Mooron wrote:
Is the brace located at 25% of the arm's length? I believe the
hydraulic ram
is located at 50% or more of the arm length.

Some are, some aren't.

It's pretty clear that you're not interested in facts, you're
interested
in arguing.

I even posted a URL to a pic of one. And then he 'claimed' that he
couldn't open it.

Scotty

"Scott Vernon" wrote in message
| Wha? Mr. 'I work in the field' has never seen a big stick crane.
| Look for a Manatowoc 4200 crawler crane.

Googled.. got zip.. I did get this.....
http://www.mammoet.com/plaatjes/pdf/7469%20Civil.pdf
Big Deal.... http://www.bucyrus.com/inthenews/world_coal-200404.pdf
I ran a crawler crane when we were setting manholes for the 96" main storm
in Ft Saskatchewan. Nothing the size of the 4200 though
I rent a 150 ton crane for haul out.... the reach requires the extra
capacity. It's a 6 ton boat.

I had a Hitachi EX200 on site the last 2 projects I supervised.
http://www.ransome-equip.com/availlongreach.html

Friggin' beaky truck drivers!

CM

"DSK" wrote in message

| It's pretty clear that you're not interested in facts, you're interested
| in arguing.

That's a ridiculous position to take considering what you presented as
counter points to date Doug

|
| I'm checking out of this thread.

I've got news for you.... you can check out but you can never leave.

CM

"Capt. Mooron" wrote

"Scott Vernon" wrote in message
| Wha? Mr. 'I work in the field' has never seen a big stick crane.
| Look for a Manatowoc 4200 crawler crane.

Googled.. got zip.. I did get this.....
http://www.mammoet.com/plaatjes/pdf/7469%20Civil.pdf
Big Deal.... http://www.bucyrus.com/inthenews/world_coal-200404.pdf
I ran a crawler crane when we were setting manholes for the 96" main
storm
in Ft Saskatchewan. Nothing the size of the 4200 though


Then you know what I meant about a topping lift?



I had a Hitachi EX200 on site the last 2 projects I supervised.
http://www.ransome-equip.com/availlongreach.html

All I see on that site are a bunch of Long reach excavators, which BTW
have their rams attached to the boom at 25% the length. Didn't some
one here claim that this was impossible?

Scotty

"Scott Vernon" wrote in message
...
| Did Doug claim otherwise? I didn't see it.

Yes it was the crux of the discussion.

CM

Nav wrote:
You may be confused. Perhaps you would like to re-read your earlier
post? I'll highlight it for you:


DSK wrote:
That's why triangular sections have the greatest rigidty for
their cross section area, and square sections are more rigid than
oval or round.


You did say most rigid didn't you? I'd say that rigid means best able to
resist bending -but perhaps you have some other use of the term? It's
strange but engineering texts say that the section that best resists
bending is an I or T section.


No, engineering texts say that "I" or "T" sections have the greatest
rigidity *in a defined plane*.

... But Doug is always right

Nope, I've been wrong several times. But this isn't one of them.

... so we must all be
wrong!

Who's "we" kimosabe?

BTW do you know what a cosine is? If you have the slightest clue about
any sort of engineering ... or even high school geometry... then my
diagram should be relatively easy to understand for you...

The compression force on the boom is the cosine of what angle?
What is that strange symbol on the mast represent? I believe earlier you
claimed the force on the mast had to be the exact same as the weight
suspended from the boom? Care to backpedal on that one, or don't you
understand what you yourself said?

DSK

"Scott Vernon" wrote in message

| All I see on that site are a bunch of Long reach excavators, which BTW
| have their rams attached to the boom at 25% the length. Didn't some
| one here claim that this was impossible?
|

I never claimed impossible..... but I may have utilized poetic license to
present an arguable counter-point.....
My point still being that a topping lift can carry a greater load than a
vang in lifting objects with a boom.

CM

"Capt. Mooron" wrote in message
...

"Scott Vernon" wrote in message

| All I see on that site are a bunch of Long reach excavators, which
BTW
| have their rams attached to the boom at 25% the length. Didn't
some
| one here claim that this was impossible?
|

I never claimed impossible..... but I may have utilized poetic
license to
present an arguable counter-point.....


poetic license? is that a fancy way of back pedaling?


Scotty

"Scott Vernon" wrote in message

| poetic license? is that a fancy way of back pedaling?

Absolutely not..... I never backpedal going downhill.

CM

Speaking of downhill, I just finished up the paper work for the last
few weeks. Sent out almost $18k in bills. I think I can coast a little
now. Maybe take a few days off and go sailing. Sound good?

Scotty


"Capt. Mooron" wrote in message
...

"Scott Vernon" wrote in message

| poetic license? is that a fancy way of back pedaling?

Absolutely not..... I never backpedal going downhill.

CM

Wish I could get time to take off myself.... I'm waiting to see if they go
ahead with a planned project for me to supervise. It's 2 months of 7/12s
but they have a strike to contend with.

CM




"Scott Vernon" wrote in message Maybe take a few
days off and go sailing. Sound good?
|
| Scotty
|
|
| "Capt. Mooron" wrote in message
| ...
|
| "Scott Vernon" wrote in message
|
| | poetic license? is that a fancy way of back pedaling?
|
| Absolutely not..... I never backpedal going downhill.
|
| CM
|
|
|
|
|
|