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DSK
 
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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

 
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