Originally posted by Frans
A pic. of the log we used
How much did the log weigh? If you have a number did you arrive at this by actually weighing it or by using a green log weight chart?
[/B][/QUOTE]We dropped the log approx 15' using 5/8" &3/4" line. The devices both walked up the trunk. Failures came at the marl. and also when the rope doubled up on itself on the drum it melted and broke within the wrap. Ken called it thermal breakdown.
Frans [/B][/QUOTE]
How many drops did each rope take before it broke?
It seems that the drops were straight down and did not exactly imitate the arc that a log follows when it is butt hitched into a rigging system. Which way do you think generates more force on the ropes and friction device, dropping the piece straight down, or creating an arcing swing?
The arc created by the notch and the pulley block means that the log slams back into the trunk, creating a different force on the trunk from what the trunk experienced in these tests. I know that you were evaluating just the friction devices in these drop tests, but, as Riggs pointed out in the thread on TB, we may be so impressed with the strength of our rigging gear that we overlook the real weak link in the system--the tree itself.
Thanks for posting all of this, it is very interesting. I hope the DVD will be made available.
Mahk