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West Wight Potter Mailing List maintainer
dfarrell@ridgecrest.ca.us
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One principle that helps to clear up some of the questions about multiple
lines is that as long as a line runs freely over pulleys (blocks) it must
have the same tension at each point along the line. Given that, if you count
the number of lines actually supporting the load (the centerboard in this
case), you can divide the weight of the load by the number of lines.
support
-------
\/\/~~~~~~~~~~ 100 pounds->
load
400 pounds
4 lines supporting 400 pounds equals 100 pounds per line. Since tension is
equal everywhere along that line, the pull at the winch is just 100 pounds.
Friction was mentioned. This affects moving the load and makes it harder to
pull the centerboard up and makes it harder for the centerboard to start down
again. It does not affect the resting weight. Note how hard it is to pull up
the mainsail (much more that its weight) yet on releasing the mainsail you
must often pull on the sail to help it down.
Hope this helps, Cliff in PA
This archive was generated by hypermail 2b29 : Tue Feb 29 2000 - 03:27:08 PST