DSK wrote:

Nav wrote:

Hey, why not look up the references.


Hey, why not look in ones that are just a tad more specialized & accurate?

Sure. Now you've had a chance to look it up. Now why not tell us the
answer?

We can take this as an admission that you don't know.


You know, I've had more intelligent conversations than this with 3 year
old.


Considering that you haven't a clue how to resolve forces on a
free-body diagram (merely the latest of a long string of your
revealed inabilities) there is no way you could have even started mine.



Isn't it strange that I resolved the forces in the free body diagram
in the topping lift case


Isn't it strange that you now claim you did, but at the time you
stumbled out a partial answer that was not even in the right ball park.
The Google archive is only about 20 seconds away, shall I quote you
*again* so soon, Navsprit?


Still trying to prop up the BIG LIE Doug? "Now claim" did I? I gave you
the answer immediately. The record plainly shows you could not solve a
freshman engineering problem. So, come one show us my answer again. And
then let's confirm your failure to produce any answer at all. Since you
claim it, show us why my answer is not in the "right ballpark". After
all, if you can't show why my answer is wrong it's pretty clear you are
just a silly little man naysaying to try to inflate his importance.

Times up Doug, put up or shut up.

Cheers

Nav wrote:
You know, I've had more intelligent conversations than this with 3 year
old.

I'm not so sure. Maybe a 4 year old, but you seem to be a bit above the
3 year old level. Except when you have these tantrums.


Considering that you haven't a clue how to resolve forces on a
free-body diagram

Nav wrote:
... Since you
claim it, show us why my answer is not in the "right ballpark".

http://groups.google.com/groups?hl=e...oogle%2BSearch

http://groups.google.com/groups?hl=e....nz%26rnum%3D1


... After
all, if you can't show why my answer is wrong it's pretty clear you are
just a silly little man naysaying to try to inflate his importance.

Well, you did not know how to state the problem correctly. You did not
once say that the tension on the topping lift would be greater than the
weight suspended from the boom end. Your figure for compression on the
boom was wrong, as should have been obvious by inspection. You did not
mention any force couple on the mast until after I had explained it to you.

Instead you keep insisting that I must be wrong. Well, maybe, but you
can't seem to prove it by any accepted standard.


Times up Doug, put up or shut up.

Your own words in the above linked threads prove everything I said
above, Navsprit. It is unpleasant to admit when you're wrong. I don't
like it myself, but then it's much more rare for me.


Now, when are you going to discuss the details of the ship propulsion
plant you know so much about, the one that the engine is stopped "by
opening a bypass valve"? When are you going to show us how figure out
prop slip? How about discussing schooner rig terminolgy? When are you
going to explain your specialized theory of tidal gravity wherein two
masses exert a single gravitational force? Should be a Nobel Prize in
that one!

DSK

DSK wrote:


... Since you
claim it, show us why my answer is not in the "right ballpark".


http://groups.google.com/groups?hl=e...oogle%2BSearch


http://groups.google.com/groups?hl=e....nz%26rnum%3D1



Like I said, these refs. show you gave _no_ answer. They do show your
attempt to wheedle out of the problem by suggesting that that question
did not formulate the problem by not including the word "perfectly" ...

I even asked you to explain the "cosine" you claimed on numerous
occasions but you avoided that too. As the record shows you could not do
the problem so it shows that you could not really have any idea as to
whether it is better to use the vang as a lifting device. That was the
point of the exercise -to stop your BS and put the argument on a
concrete basis (and you like concrete bases don't you?).

What amuses me more is that, even months later, you don't know that the
correct answer to the topping lift case is 200 x 10/17. I had hoped that
this simple hook would get you thinking about the problem rather than BS
about a rather fundamental issue. It's failure shows me that, despite
your claims, you are no engineering fish. I expected you to be able to
show that there is no boom compression in the vang case and that the
boom is only trying to bend. Do you actually have any engineering
qualifications?

Cheers

DSK wrote:

Nav wrote:

You know, I've had more intelligent conversations than this with 3
year old.


I'm not so sure. Maybe a 4 year old, but you seem to be a bit above the
3 year old level. Except when you have these tantrums.


Considering that you haven't a clue how to resolve forces on a
free-body diagram


Nav wrote:

... Since you
claim it, show us why my answer is not in the "right ballpark".


http://groups.google.com/groups?hl=e...oogle%2BSearch



Say:

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?

Is that mast perfectly vertical? Is the boom perfectly horizontal?


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.

??? The compression on the boom depends on the angle betweenthe topping
lift & the mast, thus you cannot solve the problem with the info given.
For the record, the compression on the boom would be the weight
multiplied by the cosine of the angle.

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

That depends on how hard you're talking at it.

Yes, as I said, no answer from you but one from me.

Cheers

DSK wrote:

When are you
going to explain your specialized theory of tidal gravity wherein two
masses exert a single gravitational force? Should be a Nobel Prize in
that one!

Doug, you are just embarassing yourself again. Go away and read the
reference Jeff posted. You may then see that the key is rotation +
gravity and not just the gravity field (but I have doubts you will
understand it).

Cheers

Nav wrote:

Yes, as I said, no answer from you but one from me.

Yes, as you said... an answer from you... a wrong answer, with no
attempt to explain how you reached it, no mention of any of the other
forces on the system, and total backpedalling once I showed how to set
up the porblem and hinted at resolving all the forces which you could
not identify.

A fine example, Navvie.

DSK

DSK wrote:

Nav wrote:


Yes, as I said, no answer from you but one from me.


Yes, as you said... an answer from you... a wrong answer, with no
attempt to explain how you reached it, no mention of any of the other
forces on the system, and total backpedalling once I showed how to set
up the porblem and hinted at resolving all the forces which you could
not identify.


Now, what other forces are there except those arising from the system?
Please show us how to solve the problem "you set up". We've all ben
waiting months for your expose!

Cheers