Even the smallest trees have substantial strength, species dependent of
course (some have no tap root and only surface structure). Bind LOW on
the tree to make the pull closest to the anchor of the tree (the roots).
Vehicle frames are much stronger than a piece of typical (for antennas)
copper wire, no worries. Even the smallest car can handle the strain of
a SMALL trailer (or passengers of large girth), BUT one should move
slowly to not shock load the wire or vehicle AND (in addition to the
excellent advice given) the safe zone is any place further away than the
total length of the wire plus at least 20% (factor in stretching) since
it may whip upon snapping. While it's slightly possible that it could
snap in multiple places and become airborne, distance is your friend.
When in doubt, use another tree as a shield PLUS distance and safety
equipment (hard hat, goggles etc.).
Rick nhc
On 2/11/2016 12:13 PM, Bill Frantz wrote:
Trees are quite strong. When we do demonstrations by breaking
equipment during cave rescue classes, we use trees as anchors and a
truck with an electric winch attached to one tree. Some of these
things break at several thousand pounds force. (We measure the force
with a load cell.)
The basics for tree anchors:
(1) Make sure the tree is alive and healthy.
(2) Wrap the tree with a tarp or heavy cloth to protect its bark from
damage.
(3) Then wrap it with 2" nylon webbing at least 3 times. Use a water
knot to join the webbing. Leave the knot facing the load and pull the
rest of the loops out to a carabiner or quick link rated for the
expected load. This arrangement gives you a chance of being able to
untie the know when you are finished. (2" tubular webbing is rated at
4000#. If you pull two loops, that is 4 strands and 16000#. Derate by
50% for knots, bends around carabiners etc and get 8000#.)
(4) If you are breaking things, such as #8 copper wire, cover them
with blankets to minimize the danger of having them snap through the air.
(5) Keep everyone far enough away so flying wire won't hit them, or
keep them in a closed vehicle.
73 Bill AE6JV
On 2/11/16 at 6:34 AM, [email protected] (Dauer, Edward) wrote:
I wondered what 700 or 800 pounds of shear force would do to an
automobile frame, assuming attachment to a suitable bolt somewhere.
Or would the tree fall over first?
-----------------------------------------------------------------------
Bill Frantz | Security is like Government | Periwinkle
(408)356-8506 | services. The market doesn't | 16345 Englewood Ave
www.pwpconsult.com | want to pay for them. | Los Gatos, CA 95032
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