"SAIL LOCO" wrote in message
|
| LOL........... As always your too full of yourself.

So in effect what you are stating is that you didn't understand the topic at
hand??

Clever!

CM

So in effect what you are stating is that you didn't understand the topic at
hand??.

In case you lost track there were actually 2 sub topics going on under the one
subject header. I contributed to one and not the other. The "other" is just a
rehash of the lever arm effect of a boom that took place about 6-8 months ago.
I answered it then. You should have printed it out and saved it.
S/V Express 30 "Ringmaster"
"Trains are a winter sport"

"SAIL LOCO" wrote in message
| In case you lost track there were actually 2 sub topics going on under the
one
| subject header. I contributed to one and not the other.

H-m-m-m... since you felt somehow obligated to reply to a discussion with
Doug... who actually knows what he's talking about and can present an
counter-point with sufficient arrogance and wit to warrant a modicum of
forethought prior to a rebuttal.... you manage to contribute this 'gem'...

No, what looks cool are big boat booms with holes in them.


Awesome!!

Really!

The "other" is just a
| rehash of the lever arm effect of a boom that took place about 6-8 months
ago.
| I answered it then. You should have printed it out and saved it.

Yes loco... I'm certain you solved that in short order.... unfortunately
the only reference I've found in the archives relates to you siding with
someone else's conclusions. .... but as usual not offering a logical reason
as to why.

Are you having Jax over for Crab Cakes anytime soon???.... you two should
'Talk"!!

Really!

CM

| ...And the compression on the mast is likely to
| be a multiple of the weight involved.

Capt. Mooron wrote:
No Doug.... I believe that assumption to be incorrect... you fail to
incorporate the dispersion of the load from the mast head to compression of
the mast and delivery of portions of the load to the shrouds.

???

Are you saying that shrouds & stays push up on the mast?


... When you
transfer the load to the vang alone [ via the boom].. the mast is only
subject to a side load from the vang fitting and all the force is supported
by the boom/vang. None of the load is distributed to the entire mast or the
shrouds. In other words any portion of the mast above the boom is not
utilized in the dispersion of the forces generated by the bearing loads.

Please explain further. How is this load "dispersed"? Into the air, maybe?


The only thing muddy here is your refusal to approach this with an open
mind..

If having an open minds leads to conclusions like that above, then I'm
better off (from the engineering standpoint) without.

Fresh Breezes- Doug King

Sounds similar to a thread where you were rebutting a Kerry bashing.

Is this the best you can do?

"DSK" wrote

Are you saying that shrouds & stays push up on the mast?

"The best" is what is true & real.

Shrouds don't push up on a mast and do not "disprse" any loads.

Kerry bashing by paid shills is a poor reason to decide a vote.

"I never give them hell. I just tell the truth and they think it's hell."
--Harry S. Truman

Bart Senior wrote:
Sounds similar to a thread where you were rebutting a Kerry bashing.

Is this the best you can do?

"DSK" wrote

Are you saying that shrouds & stays push up on the mast?

Doug I didn't get your last post... can you repost it so I can attack your
position with some decorum... Thnx ;-)

CM

| "DSK" wrote
|
| Are you saying that shrouds & stays push up on the mast?
|
|
|
|

Capt. Mooron wrote:
Doug I didn't get your last post... can you repost it so I can attack your
position with some decorum... Thnx ;-)

Sorry, it's gone with the wind. However, I can probably remember the
gist of it well enough.

You said that the shrouds "disperse" the load, which is crazy. Shrouds
keep the mast from falling over, at the cost of placing the mast under
compression. A side load on the mast increases tension on the shroud,
which increases compression on the mast. So, the compression on the mast
will *always* be greater than the weight load placed on it... and that's
not taking into account the static tension on the rig (pre-load).

The difference between a boom holding a heavy weight, supported by a
topping lift; and one supported by a solid vang is this:

The topping lift will transfer the weight to the masthead, increasing
compression on the mast. The shrouds keep the mast from falling towards
the weight, increasing compression on the mast. The boom is in
compression, keeping the weight from swinging in towards the mast. The
compression on the mast & tension on the shrouds place a torsion load on
the hull.

The solid boom vang will be in compression. The boom will be in torsion
between the weight pulling down and the vang pushing up. The mast will
have a torsion load on it from the gooseneck to the lower boom vang
swivel fitting.

Last but not least, booms supported by solid vangs will (if properly
engineered) hold up weights at least as heavy as a medium size adult.
Ask me how I know this for a fact!

Fresh Breezes- Doug King

"DSK" wrote in message
| You said that the shrouds "disperse" the load, which is crazy. Shrouds
| keep the mast from falling over, at the cost of placing the mast under
| compression. A side load on the mast increases tension on the shroud,
| which increases compression on the mast. So, the compression on the mast
| will *always* be greater than the weight load placed on it... and that's
| not taking into account the static tension on the rig (pre-load).

Okay I can agree with the premise that the shrouds provide stability [via
tension].... but the fact that they are attached to the mast indicates
that a transmission of stress is allocated to the shrouds.


|
| The difference between a boom holding a heavy weight, supported by a
| topping lift; and one supported by a solid vang is this:
|
| The topping lift will transfer the weight to the masthead, increasing
| compression on the mast. The shrouds keep the mast from falling towards
| the weight, increasing compression on the mast. The boom is in
| compression, keeping the weight from swinging in towards the mast. The
| compression on the mast & tension on the shrouds place a torsion load on
| the hull.

I concur.. that seems to be a logical dispersion of forces.

|
| The solid boom vang will be in compression. The boom will be in torsion
| between the weight pulling down and the vang pushing up. The mast will
| have a torsion load on it from the gooseneck to the lower boom vang
| swivel fitting.

Again I concur...

|
| Last but not least, booms supported by solid vangs will (if properly
| engineered) hold up weights at least as heavy as a medium size adult.
| Ask me how I know this for a fact!

Although I agree with this... my argument was regarding the actual load
capacity between the vang and the topping lift. My point is the topping lift
is able to handle much greater loads than the vang ever could. On this
aspect I stand my ground.... the topping lift has the mechanical advantage
over the vang.

CM


|
| Fresh Breezes- Doug King
|

Doug,

Can you say "GIN POLE?" That is what the boom becomes with a topping
lift Hoist.

Capt. Mooron wrote:
Although I agree with this... my argument was regarding the actual load
capacity between the vang and the topping lift. My point is the topping lift
is able to handle much greater loads than the vang ever could.

Well, if they're both engineered appropriately, why?


.... the topping lift has the mechanical advantage
over the vang.

If you mean "the topping lift is directly opposite the weight, while the
solid vang has to support a multiple of the weight" then I agree. But
that ignores the fact that modern materials and engineering are well
equal to the task. OTOH if you're limited to Stone Age technology, then
solid vangs are not going to work too well, no.

Fresh Breezes... Doug King

"DSK" wrote in message
| Capt. Mooron wrote:
| Although I agree with this... my argument was regarding the actual load
| capacity between the vang and the topping lift. My point is the topping
lift
| is able to handle much greater loads than the vang ever could.
|
| Well, if they're both engineered appropriately, why?

Because Doug... all things being equal and even when the maximum engineering
and materials are utilized... with the current location of the vang on a
boom
" .... the topping lift has the mechanical advantage over the vang."
Always will...

| If you mean "the topping lift is directly opposite the weight, while the
| solid vang has to support a multiple of the weight" then I agree. But
| that ignores the fact that modern materials and engineering are well
| equal to the task. OTOH if you're limited to Stone Age technology, then
| solid vangs are not going to work too well, no.

Don't try and worm your way out now Doug! ;-)
No new fangled materials or honeycombed booms will ever change the fact that
the load point at the end of the boom will be subject to mechanical
advantage. Since placing the of the vang to that point is not an acceptable
option... it will retain it's loss of mechanical advantage no matter what
materials are utilized. [caveat-all structures being equally engineered]

Stick that in your Field Book.... I may not be an Engineer... but I'm a
Technician ... and usually train you guys till you get out of diapers and
into a Ring! :-P

You don't scare me Man!

CM

Because you've seen someone step up onto the boom to do some work, as did
the skipper during the Trans-Erie, he had to re-run a jiffy reefing line
through a reef clew grommet. You some of the folks here are taking up the
arguments of the lately departed Captain Neal, who never met an improvement
in sailing technology that he didn't like.
John Cairns

"DSK" wrote in message
. ..
Last but not least, booms supported by solid vangs will (if properly
engineered) hold up weights at least as heavy as a medium size adult.
Ask me how I know this for a fact!

Fresh Breezes- Doug King

Good Grief John.... how can you miss the point of this whole discussion so
adeptly.

Nobody is arguing the merits of the technology... what is being debated is
the advantage in capacity between a topping lift and a vang.

....and by the way... since when do you undertake the option of never
questioning "improvements in sailing technology"?

CM



"John Cairns" wrote in message
m...
| Because you've seen someone step up onto the boom to do some work, as did
| the skipper during the Trans-Erie, he had to re-run a jiffy reefing line
| through a reef clew grommet. You some of the folks here are taking up the
| arguments of the lately departed Captain Neal, who never met an
improvement
| in sailing technology that he didn't like.
| John Cairns
|
| "DSK" wrote in message
| . ..
| Last but not least, booms supported by solid vangs will (if properly
| engineered) hold up weights at least as heavy as a medium size adult.
| Ask me how I know this for a fact!
|
| Fresh Breezes- Doug King
|
|
|

Slow down, Mooron. I was merely verifying what Doug mentioned, I assuming
that's what he was referring to, the ability of a rigid vang to support the
weight of an individual standing on the boom. I wasn't necessarily referring
to you when I talked about "improvements in sailing technology" Of course
the boom end is supported better by a topping lift on the end than it is by
a rigid vang mounted a quarter of a way along it's length. But a rigid still
offers enough support to hoist someone out of the water with the end of the
boom, or lift an auxiliary out of the engine compartment. Not that I never
question the merits of "technology improvements", I like to think I try to
keep a fair amount of skepticism when I see words like"new and improved",
but I don't reflexively assume that improvements aren't just that. In any
event, I wouldn't think that capacity is an issue when debating the merits
rigid boom vangs. One last point, if you retrofit a rigid vang to you boat
you still have a topping lift to use for things like hoisting someone to the
masthead, or hoisting an auxiliary out of your engine compartment, etc. BTW,
I'm not rushing out to buy a rigid vang for my boat, it's fairly low on my
list of future boat improvements.
John Cairns


"Capt. Mooron" wrote in message
...
Good Grief John.... how can you miss the point of this whole discussion so
adeptly.

Nobody is arguing the merits of the technology... what is being debated
is
the advantage in capacity between a topping lift and a vang.

...and by the way... since when do you undertake the option of never
questioning "improvements in sailing technology"?

CM



"John Cairns" wrote in message
m...
| Because you've seen someone step up onto the boom to do some work, as
did
| the skipper during the Trans-Erie, he had to re-run a jiffy reefing line
| through a reef clew grommet. You some of the folks here are taking up
the
| arguments of the lately departed Captain Neal, who never met an
improvement
| in sailing technology that he didn't like.
| John Cairns
|
| "DSK" wrote in message
| . ..
| Last but not least, booms supported by solid vangs will (if properly
| engineered) hold up weights at least as heavy as a medium size adult.
| Ask me how I know this for a fact!
|
| Fresh Breezes- Doug King
|
|
|

John,

The improvements in boom technology as demonstrated by the Kiwi's Boom
in the last AC Races wasn't accepted by you and Doug as being better?

This long, long discussion was originally about doing away with the
topping lift because the use of the Rigid Vang could do everything as
well, with the exception of a spare back stay. The Hoisting ability of
the Solid vang was questioned.

The hoisting ability of the boom with the solid vang presents a
completely different engineering limit than the topping lift. SHEAR!
Shear creates a serious weakness when hoisting with the boom with end
support. Especially with new booms to make the lighter. The improved
booms of today are not meant for end loading with shear pressure.
This was demonstrated very well on that POS that the KIWI used to
defend the AC.

Ole Thom

John,

I forgot to meantion that Bart's statement about the Rigid Vang would
let him get rid of the topping lift.

Ole Thom

Thom Stewart wrote:
... The improved
booms of today are not meant for end loading with shear pressure.

Shear or torsion?

This was demonstrated very well on that POS that the KIWI used to
defend the AC.

I was unaware that the Kiwis boom broke when they were trying to hoist a
heavy weight on the end of the boom. I thought it broke under normal
sailing loads... by definition, poor engineering.

I grant you that poor engineering exists. I dispute that the existence
of poor engineering proves that good engineering does not exist.

DSK

Thom Stewart wrote:
Can you say "GIN POLE?"

Thom, put down the bottle and back away slowy...

... That is what the boom becomes with a topping
lift Hoist.

Ah, now I see your point. Yes.

So?

DSK

Get rid of having to use one to keep the boom up, sure, but actually
removing the topping lift would be silly. All sorts of uses for the topping
lift, emergency backstay, extra main halyard, safety line for bosun's chair
work. I vaguely recall someone mentioning a rigger talking about removing
the topping lift, can't imagine a competent rigger suggesting this.
John Cairns
"Thom Stewart" wrote in message
...
John,

I forgot to meantion that Bart's statement about the Rigid Vang would
let him get rid of the topping lift.

Ole Thom

Doug,

Wouldn't torsion be a twisting load?

The KIWI boom failed at the end when it was use for other than Outhaul
tension. Poor engineering to be sure but getting off the subject. It is
in response to the comment of "Stone Age Engineering"

Ole Thom

"John Cairns" wrote in message
m...
| Slow down, Mooron. I was merely verifying what Doug mentioned, I assuming
| that's what he was referring to, the ability of a rigid vang to support
the
| weight of an individual standing on the boom.

No John.. I believe Doug's premise is that a properly engineered vang can
equal the capacity of a topping lift... that I dispute.

I wasn't necessarily referring
| to you when I talked about "improvements in sailing technology" Of course
| the boom end is supported better by a topping lift on the end than it is
by
| a rigid vang mounted a quarter of a way along it's length.

Excellent ... then we are in agreement


But a rigid still
| offers enough support to hoist someone out of the water with the end of
the
| boom, or lift an auxiliary out of the engine compartment.

Allow me to put to you 2 separate scenarios... a rigid vang on a 20 footer
and a rigid vang on a 50 footer. Now... on the 20 footer it's obvious the
weight of a man on the end of the boom would tax the rigid vang.... but not
the topping lift. The weight of a man on the end of a boom on the 50 foot
boat would not tax the vang.... nuff said.


Not that I never
| question the merits of "technology improvements", I like to think I try to
| keep a fair amount of skepticism when I see words like"new and improved",
| but I don't reflexively assume that improvements aren't just that. In any
| event, I wouldn't think that capacity is an issue when debating the merits
| rigid boom vangs.

Not unless you decide to compare mechanical capacities between the vang and
the topping lift


One last point, if you retrofit a rigid vang to you boat
| you still have a topping lift to use for things like hoisting someone to
the
| masthead, or hoisting an auxiliary out of your engine compartment, etc.
BTW,
| I'm not rushing out to buy a rigid vang for my boat, it's fairly low on my
| list of future boat improvements.

Yes.... I concur ... but the discussion was regarding the capacity of the
vang compared to the topping lift. Both have their functions... and for
hoisting the topping lift has the advantage by a large margin.

CM

Capt. Mooron wrote:
No John.. I believe Doug's premise is that a properly engineered vang can
equal the capacity of a topping lift... that I dispute.

And you're wrong.

Allow me to put to you 2 separate scenarios... a rigid vang on a 20 footer
and a rigid vang on a 50 footer. Now... on the 20 footer it's obvious the
weight of a man on the end of the boom would tax the rigid vang....

Not necessarily. It depends entirely on how the rig is built.

You assume that the rig, particularly the boom, and the vang must be
weak. It ain't so.

I suspect that you cannot envision a box section boom, or a custom
section boom. Have you ever seen a boat where the boom was not the same
extruded section as the mast? They exist.

Furthermore, I suspect you have little to no experience with fractional
rigs. A tapered spar is not built to take huge compression loads at the
mast head. OTOH they can easily be built to take a heck of a torsion
load at the gooseneck... some have solid struts supporting the mast just
at or just below the gooseneck.

Your statements about rigid vangs are like the yokel who was shown a
picture of a giraffe and said "there cain't be no such anny-mal."

DSK

"DSK" wrote in message
...
| Capt. Mooron wrote:
| No John.. I believe Doug's premise is that a properly engineered vang
can
| equal the capacity of a topping lift... that I dispute.
|
| And you're wrong.

No I'm not!

|
| Allow me to put to you 2 separate scenarios... a rigid vang on a 20
footer
| and a rigid vang on a 50 footer. Now... on the 20 footer it's obvious
the
| weight of a man on the end of the boom would tax the rigid vang....
|
| Not necessarily. It depends entirely on how the rig is built.

Oh here we go.... the sidewind of the engineer in dire straits.... let's
bring "specialty" manufacturing alloys and specific design criteria into the
equation! It's a smoke screen and I'm not falling for it.



| You assume that the rig, particularly the boom, and the vang must be
| weak. It ain't so.

That's totally incorrect... I never stated such a thing nor utilized any
such reasoning in my argument.

|
| I suspect that you cannot envision a box section boom, or a custom
| section boom. Have you ever seen a boat where the boom was not the same
| extruded section as the mast? They exist.

Pardon Me Doug... who the hell do you think you are discussing with here..
jaxxies or horvath???
Your suspicions are as unfounded as your initial position regarding the
suitability of a vang for hoisting.
What I suspect is that you've suddenly realized the logic of my statement
are finding yourself at a loss to formulate a rational defense.


|
| Furthermore, I suspect you have little to no experience with fractional
| rigs.

That's a rather cocky and mistaken assumption on your part Doug...

A tapered spar is not built to take huge compression loads at the
| mast head. OTOH they can easily be built to take a heck of a torsion
| load at the gooseneck... some have solid struts supporting the mast just
| at or just below the gooseneck.

Oh yeah... let's hide behind the vagaries of specific engineering in an
attempt to mask the basic tenets of the discussion... that vangs were never
designed to hoist.

|
| Your statements about rigid vangs are like the yokel who was shown a
| picture of a giraffe and said "there cain't be no such anny-mal."

Now that is just desperate and totally uncalled for.... don't be an ass
with me Doug.. I don't tolerate such gibberish. If you can't present a
viable argument to back your contentions... you have already lost the
argument before you decided to discuss it. I demand the same respect I've
shown you... and if you find yourself unable to continue this debate without
reducing your counterpoints to suggestions that I'm not up to the task of
basic comprehension... then it's time for you to pack it up and run along.

Understand this.... every poster that has joined this discussion has found
in my favour regarding the suitability of the topping lift versus the vang
for hoist situations.

CM

To those that might join this forever discussion;

Go back and read the posting on this subject of Aug 17. Bart's desire
to do away with his topping lift, My reasons for keeping the topping
lift, Doug's exceptions to my reasoning.

Doug has debated the issue into a boom, solid vang design.

Ole Thom

Doug,

A tapered Spar (Mast) held in rig by a fore stay, a back stay, Upper
star'b an Port Shrouds and Inter medium shrouds/ with spreaders are sure
as hell more than capable of supporting a man. Very often, in racing
circles, you will see a man sent aloft to look for wind sitting on the
upper spreaders. This is the type of strength the topping lift can
deliver to a hoist. A boom vang cannot.

Give it up Doug, the horse is dead, beating it won't help. Bury it.

Ole Thom

Capt. Mooron wrote:
Oh here we go.... the sidewind of the engineer in dire straits.... let's
bring "specialty" manufacturing alloys and specific design criteria into the
equation! It's a smoke screen and I'm not falling for it.

It's a "smoke screen" to say that equipment should be designed & built
to do it's job??


| You assume that the rig, particularly the boom, and the vang must be
| weak. It ain't so.

That's totally incorrect... I never stated such a thing nor utilized any
such reasoning in my argument.

Well, you keep saying over and over, "It can't be as strong as a topping
lift" as though somehow calling a piece of rigging 'topping lift'
magically renders it invulnerable.


|
| I suspect that you cannot envision a box section boom, or a custom
| section boom. Have you ever seen a boat where the boom was not the same
| extruded section as the mast? They exist.

Pardon Me Doug... who the hell do you think you are discussing with here..
jaxxies or horvath???

That may have been a bit over the top. I apologize.

But you sure don't act as if you ever saw any such thing. If you have,
then why all the bogus assumptions?

I gave a simple engineering explanation of the forces & stresses, which
you agreed with, and then you started right back up with "it can't
possibly be as strong." First, the matter is not one to be settled by
debate. Second, believe what you want... I have spent more time than I
should trying to explain, maybe some day you'll actually sail a properly
rigged boat with a solid vang and see for yourself.

Understand this.... every poster that has joined this discussion has found
in my favour regarding the suitability of the topping lift versus the vang
for hoist situations.

Ok, I'm glad that makes you feel better. Does that mean you "win"?

Fresh Breezes- Doug King

"DSK" wrote in message

| It's a "smoke screen" to say that equipment should be designed & built
| to do it's job??

That's not the point at all Doug..... the vang is indeed designed to do
it's job... it just seems that you fail to concede the point that the
vang's primary "job" is not to handle bearing loads delivered to the end of
the boom.

|
| Well, you keep saying over and over, "It can't be as strong as a topping
| lift" as though somehow calling a piece of rigging 'topping lift'
| magically renders it invulnerable.

No!... I said over and over that the mechanical advantage is to the topping
lift!

| That may have been a bit over the top. I apologize.

Accepted.

|
| But you sure don't act as if you ever saw any such thing. If you have,
| then why all the bogus assumptions?

Not assumptions Doug..... just basic engineering principles. The "Topping
Lift" will always have the advantage over the "Vang" in hoisting load
capacity

|
| I gave a simple engineering explanation of the forces & stresses, which
| you agreed with, and then you started right back up with "it can't
| possibly be as strong."

No .. I stated rather plainly that the advantage was to the topping lift...
by a large margin.

First, the matter is not one to be settled by
| debate.

Yes Doug it can... I present a point, you present a counter-point.. we
collectively review the data presented and submit rebuttals based on logic.
That's discussion and debate.

Second, believe what you want... I have spent more time than I
| should trying to explain, maybe some day you'll actually sail a properly
| rigged boat with a solid vang and see for yourself.

I think you'd better give your head a shake.... you have explained
nothing... you have obfuscated and side tracked, you've attempted to bring
in a plethora of variables to substantiate your claims. You have provided
very little in the form of actual, logical counter points to my statements.
You've been reduced to brash accusations regarding my experience.... and
now you lament wasted time.... the reasoning of a failed argument.

| Ok, I'm glad that makes you feel better. Does that mean you "win"?

No Doug... what it means is that despite your attempts at introducing wild
variables... the basic logic of my statement is understood by those who have
bothered to read this far into our debate.

That alone may be the sum total of your inability to close with this.... you
refuse to entertain it as a discussion and rather approach it as a contest.
You gain nothing in a contest... you gain information via discussion.....
but only if you are willing to grant favour to logic rather than emotion.

In regards to abilities to discuss topics... my Father always insisted on
regular discussions since I was very young.... on a wide subject of
materials... the onus /responsibility for research was placed upon us ...
and insisted we be able to defend points of view we did not agree with....
if only to better understand the complexities of differing points of view
and hone our abilities to present them.

It's a skill that still stands me well.... ;-)

CM

Capt. Mooron wrote:
That's not the point at all Doug..... the vang is indeed designed to do
it's job... it just seems that you fail to concede the point that the
vang's primary "job" is not to handle bearing loads delivered to the end of
the boom.

For a solid vang, it need not make any difference.



|
| Well, you keep saying over and over, "It can't be as strong as a topping
| lift" as though somehow calling a piece of rigging 'topping lift'
| magically renders it invulnerable.

No!... I said over and over that the mechanical advantage is to the topping
lift!

And I explained over and over (and over and over) why that is not
necessarily the case.



I think you'd better give your head a shake.... you have explained
nothing... you have obfuscated and side tracked

Bull puckey. You could have the textbook in front of you and still
insist that *you're* right and the prof & book *must* be wrong. A
classic case.

In regards to abilities to discuss topics... my Father always insisted on
regular discussions since I was very young....

Did he ever use a 2x4?

Regards
Doug King

"DSK" wrote in message
...
| Capt. Mooron wrote:
| That's not the point at all Doug..... the vang is indeed designed to do
| it's job... it just seems that you fail to concede the point that the
| vang's primary "job" is not to handle bearing loads delivered to the end
of
| the boom.
|
| For a solid vang, it need not make any difference.


A statement with no qualifiers..... it need not if the weight is within the
capacity of the vang... which will always be far less than the capacity of
the topping lift.

| |
| | Well, you keep saying over and over, "It can't be as strong as a
topping
| | lift" as though somehow calling a piece of rigging 'topping lift'
| | magically renders it invulnerable.
|
| No!... I said over and over that the mechanical advantage is to the
topping
| lift!
|
| And I explained over and over (and over and over) why that is not
| necessarily the case.

another statement with no qualifier.... not necessarily the case as long as
the load is within capacity of the vang which unless you are using cooked
linguini for the topping lift... is far less then the mechanical advantage
of the topping lift.

|
|
|
| I think you'd better give your head a shake.... you have explained
| nothing... you have obfuscated and side tracked
|
| Bull puckey. You could have the textbook in front of you and still
| insist that *you're* right and the prof & book *must* be wrong. A
| classic case.

The "prof & book" side with me in this case Doug.... try again

|
| In regards to abilities to discuss topics... my Father always insisted
on
| regular discussions since I was very young....
|
| Did he ever use a 2x4?

Only when I lost ...... as you can see that won't happen here because I
actually researched the subject at hand. You should try that avenue instead
of your current tact of repetition of erroneous data... ad nausea

CM

DSK wrote:
And the compression on the mast is likely to
be a multiple of the weight involved.

Oh boy! I though you said you knew some engineering. The vertical force
is _exactly_ the weight of the lifted object Doug.

Cheers

It's kind of bizarre that a bunch of dinghy sialors talk about people
standing on the end of flimsy booms doncha think?

Cheers

John Cairns wrote:

Slow down, Mooron. I was merely verifying what Doug mentioned, I assuming
that's what he was referring to, the ability of a rigid vang to support the
weight of an individual standing on the boom. I wasn't necessarily referring
to you when I talked about "improvements in sailing technology" Of course
the boom end is supported better by a topping lift on the end than it is by
a rigid vang mounted a quarter of a way along it's length. But a rigid still
offers enough support to hoist someone out of the water with the end of the
boom, or lift an auxiliary out of the engine compartment. Not that I never
question the merits of "technology improvements", I like to think I try to
keep a fair amount of skepticism when I see words like"new and improved",
but I don't reflexively assume that improvements aren't just that. In any
event, I wouldn't think that capacity is an issue when debating the merits
rigid boom vangs. One last point, if you retrofit a rigid vang to you boat
you still have a topping lift to use for things like hoisting someone to the
masthead, or hoisting an auxiliary out of your engine compartment, etc. BTW,
I'm not rushing out to buy a rigid vang for my boat, it's fairly low on my
list of future boat improvements.
John Cairns


"Capt. Mooron" wrote in message
...

Good Grief John.... how can you miss the point of this whole discussion so
adeptly.

Nobody is arguing the merits of the technology... what is being debated

is

the advantage in capacity between a topping lift and a vang.

...and by the way... since when do you undertake the option of never
questioning "improvements in sailing technology"?

CM



"John Cairns" wrote in message
. com...
| Because you've seen someone step up onto the boom to do some work, as

did

| the skipper during the Trans-Erie, he had to re-run a jiffy reefing line
| through a reef clew grommet. You some of the folks here are taking up

the

| arguments of the lately departed Captain Neal, who never met an
improvement
| in sailing technology that he didn't like.
| John Cairns
|
| "DSK" wrote in message
| . ..
| Last but not least, booms supported by solid vangs will (if properly
| engineered) hold up weights at least as heavy as a medium size adult.
| Ask me how I know this for a fact!
|
| Fresh Breezes- Doug King
|
|
|

DSK wrote:

Thom Stewart wrote:

... The improved
booms of today are not meant for end loading with shear pressure.


Shear or torsion?


Good lord. Another engineering term not understood by you!

Cheers

DSK wrote:



Your statements about rigid vangs are like the yokel who was shown a
picture of a giraffe and said "there cain't be no such anny-mal."



Reverting to the good old ad hominem!

Cheers

DSK wrote:

Capt. Mooron wrote:

No John.. I believe Doug's premise is that a properly engineered vang can
equal the capacity of a topping lift... that I dispute.


And you're wrong.

Allow me to put to you 2 separate scenarios... a rigid vang on a 20
footer
and a rigid vang on a 50 footer. Now... on the 20 footer it's obvious the
weight of a man on the end of the boom would tax the rigid vang....


Not necessarily. It depends entirely on how the rig is built.

Ever seen a man standing at the end of a _real_ 20' boat boom supported
by just a rigid vang? Can you imagine it's bend? Try it on you dinghy
-that's about 20' -and you can block up the boom at the vang position.
Then send us the picture -since you are so sure it'll work OK!

Cheers

Capt. Mooron wrote:

"DSK" wrote in message


I think you'd better give your head a shake.... you have explained
nothing... you have obfuscated and side tracked, you've attempted to bring
in a plethora of variables to substantiate your claims. You have provided
very little in the form of actual, logical counter points to my statements.
You've been reduced to brash accusations regarding my experience.... and
now you lament wasted time.... the reasoning of a failed argument.

But if he didn't he wouldn't be Doug!

Cheers

Just for fun why not do a simple engineering calculation for us Doug?

For simplicity let's say the rig has mast without any stays.

Mast 20' vertical Boom 10' horizontal. Gooseneck 3' from base of mast
Vang attched to point 3' from goosneck. 200 lbs to be lifted.

What is the bending moment on the boom at the vang if the load is held
by the vang?
What is the shear stress on the boom the load is held by the vang?
What is the compression force of the boom at the vang attachment?

Now let me quickly solve for the topping lift case:

If a topping lift is used, the bending moment at the vang is 0.
If a topping lift is used, the shear stress is 0
If a topping lift is used, the boom compression is 200 x 10 /17 = 118 lbs.

What is the maximum stress at the vang attachment point in each case?

Cheers

Have you ever had a girlfriend, Nav?

You are incredibly smart...but incredibly boring at the same time.

Any excitement in your life?

LP (curious minds want to know)


"Nav" wrote in message
...
Just for fun why not do a simple engineering calculation for us Doug?

For simplicity let's say the rig has mast without any stays.

Mast 20' vertical Boom 10' horizontal. Gooseneck 3' from base of mast
Vang attched to point 3' from goosneck. 200 lbs to be lifted.

What is the bending moment on the boom at the vang if the load is held
by the vang?
What is the shear stress on the boom the load is held by the vang?
What is the compression force of the boom at the vang attachment?

Now let me quickly solve for the topping lift case:

If a topping lift is used, the bending moment at the vang is 0.
If a topping lift is used, the shear stress is 0
If a topping lift is used, the boom compression is 200 x 10 /17 = 118 lbs.

What is the maximum stress at the vang attachment point in each case?

Cheers

Gee whiz Nav,
how long have you been waiting to work that one into a conversation?
Scout

"Nav" wrote in message
...
Just for fun why not do a simple engineering calculation for us Doug?

For simplicity let's say the rig has mast without any stays.

Mast 20' vertical Boom 10' horizontal. Gooseneck 3' from base of mast
Vang attched to point 3' from goosneck. 200 lbs to be lifted.

What is the bending moment on the boom at the vang if the load is held
by the vang?
What is the shear stress on the boom the load is held by the vang?
What is the compression force of the boom at the vang attachment?

Now let me quickly solve for the topping lift case:

If a topping lift is used, the bending moment at the vang is 0.
If a topping lift is used, the shear stress is 0
If a topping lift is used, the boom compression is 200 x 10 /17 = 118 lbs.

What is the maximum stress at the vang attachment point in each case?

Cheers

MC,

If you fo to all tht trouble of figuring things out every time you sail, do
you ever get to relax? You should have a hibernate setting on the right
side of your brain.
"Scout" wrote in message
...
Gee whiz Nav,
how long have you been waiting to work that one into a conversation?
Scout

"Nav" wrote in message
...
Just for fun why not do a simple engineering calculation for us Doug?

For simplicity let's say the rig has mast without any stays.

Mast 20' vertical Boom 10' horizontal. Gooseneck 3' from base of mast
Vang attched to point 3' from goosneck. 200 lbs to be lifted.

What is the bending moment on the boom at the vang if the load is held
by the vang?
What is the shear stress on the boom the load is held by the vang?
What is the compression force of the boom at the vang attachment?

Now let me quickly solve for the topping lift case:

If a topping lift is used, the bending moment at the vang is 0.
If a topping lift is used, the shear stress is 0
If a topping lift is used, the boom compression is 200 x 10 /17 = 118
lbs.

What is the maximum stress at the vang attachment point in each case?

Cheers