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