DSK wrote:
Nav wrote:

Ad_hominem?


Yep. Couldn't happen to a nicer guy, too.

After the way you have acted, to get all nose-in-the-air about my poking
fun at your obsessive behavior is rather funny.


Snort.


Are you sure? The geometry _is_ defined.


You're right. Lesson 1- always look the problem over thoroughly.


Progress!


For the record, the compression on the boom would be the weight
multiplied by the cosine of the angle.


Are you saying it is not 118 lbs in the topping lift case?


Are you saying it's not the cosine of the angle formed by the topping
lift? Tell you what, go down the hall and ask one of the engineering
profs... if any will speak to you...

So you are maintaining it's the "cosine" of the angle and it's not as I
posted, 118 lbs. Interesting.


I gather that you have never heard of a "Free Body Diagram"? Freshman
engineering stuff. That is the way to solve such problems. If you
don't believe me, ask Scout.



But I'm not asking Scout. I'm asking _you_ to solve this freshman
problem -if you can.


Well, it is only a few minutes to draw up a free body diagram. I did a
rough one earlier, but it will take longer to do it on the comuter and
post it. Another job for tomorrow....



I look forward to seeing your solution. While you are at it look at that
"cosine" you so like. Perhaps you will then see why I did use a "cosine"
or any other trig. function to calculate the compression.


I wonder why the boom vang situation bothers you so much, or why you are
*so* sure that a solid vang cannot lift a heavy weight. I've seen it
done several times on several different boats, so obviously it can.


No one said it could not. The question was one of seamanship and
appropriate use of equipment, spars and rigging. Do you deny that a
given weight that will fold a boom in the vang lift will be easily
lifted by the boom if a topping lift is used?



Cheers

Nav wrote:
Snort.

One of your more clever remarks.


Are you sure? The geometry _is_ defined.


You're right. Lesson 1- always look the problem over thoroughly.

Actually, on 2nd look, you're wrong. It isn't, unless you *assume* the
mast is perfectly vertical and the boom perfectly horizontal.


Are you saying it is not 118 lbs in the topping lift case?

Probably not. With the ratios you give (assuming vertical mast & level
boom, since you don't seem capable of defining the problem correctly)
the compression is going to be somewhat less than 1/2 the weight.

And, if you look closely, you'll see that the tension on the topping
lift is *more* than the weight! Hello! How did that happen?

Wait there's more... a mysterious force has appeared on the mast!
Apparently the pulling of the topping lift and the pushing of the boom
has run amok! HELP HELP!


I gather that you have never heard of a "Free Body Diagram"?
Freshman engineering stuff. That is the way to solve such problems.
If you don't believe me, ask Scout.


But I'm not asking Scout. I'm asking _you_ to solve this freshman
problem -if you can.

I see. You're playing stalker again. Considering that you've never won
even once, is this wise?

Can *you* solve the problem, Navvie? Go ahead, ask for some advice from
down the hall! This mysterious new stress on the mast and the resolution
of forces is not obvious (although it's not terribly difficult either)
and leads to some interesting conclusions, all of which support what I
have said all along.


Well, it is only a few minutes to draw up a free body diagram.

http://community.webshots.com/photo/...79893018mpZKNO

Actually it took the longest to convert the file and upload it. What a
PITA. All to prove a stupid point.

... The question was one of seamanship and
appropriate use of equipment, spars and rigging. Do you deny that a
given weight that will fold a boom in the vang lift will be easily
lifted by the boom if a topping lift is used?

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"?

Fresh Breezes- Doug King

DSK wrote:

Nav wrote:


Are you sure? The geometry _is_ defined.



You're right. Lesson 1- always look the problem over thoroughly.


Actually, on 2nd look, you're wrong. It isn't, unless you *assume* the
mast is perfectly vertical and the boom perfectly horizontal.


Assume nothing. If it were not vertical or horizontal the angle would be
given. One wonders if you ever took any engineering courses...
Introducing "perfectly" shows a clear lack of engineering expertise and
an attempt to smoke screen. It's pretty clear you can't do it can you?


Are you saying it is not 118 lbs in the topping lift case?


Probably not. With the ratios you give (assuming vertical mast & level
boom, since you don't seem capable of defining the problem correctly)
the compression is going to be somewhat less than 1/2 the weight.

And, if you look closely, you'll see that the tension on the topping
lift is *more* than the weight! Hello! How did that happen?

Wait there's more... a mysterious force has appeared on the mast!
Apparently the pulling of the topping lift and the pushing of the boom
has run amok! HELP HELP!


Yes, you need help -the diagram is pretty much worthless and you've not
shown your incorrect "cosine" anyway . I'd say you just failed freshman
engineering.


I gather that you have never heard of a "Free Body Diagram"?
Freshman engineering stuff. That is the way to solve such problems.
If you don't believe me, ask Scout.



But I'm not asking Scout. I'm asking _you_ to solve this freshman
problem -if you can.



Actually it took the longest to convert the file and upload it. What a
PITA. All to prove a stupid point.


The point being you can't draw a proper free body diagram or solve the
problem?

... The question was one of seamanship and appropriate use of
equipment, spars and rigging. Do you deny that a given weight that
will fold a boom in the vang lift will be easily lifted by the boom if
a topping lift is used?


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"?


Such vivid imagination. Assume what you like but it's obvious from this
thread to any engineer that you don't even begin to understand basic
engineering.

Cheers

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.


.... it's obvious from this
thread to any engineer that you don't even begin to understand basic
engineering.

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.

DSK

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

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