Join Date: Nov 2008
Location: Deale, MD
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Maiximum, Average, or Minimum?
If we are talking about rope or chain, we report the minimum breaking strength (3-6 sigmas, depending...) and the safe working load (20-33%, depending...). But in anchor test reports we tend to see the maximum holding reported.
Should we instead...
* Minimum holding in X trials, with some maximum setting distance.
* Allow one throw-out, or not? Any anchor can have the misfortune of landing on trash. Any anchor can display super holding when it hooks a tree trunk or submerged tire.
In the Solmons Island testing, Fortess was the clear winner based upon maximum holding, but Manson, Ultra, and Mantus had better minimum hold. I can see a case both ways: if you are setting anchors for a major storm, taking the time to repeat the set may be fine. Once a Fortress begins to dig, complete setting is really quite dependable, more than most. On a daily basis, though, our engine set power is only a fraction of the max load; we don't want to risk a false set. I also suspect that a reliable minimum set correlates to ability to track through veers, or at least that is what the data seems to suggest.
Of course, this is all herding cats, since the variability of the bottom is enough to make you tear your hair out by the roots. I'm glad I didn't have much to begin with.
(I'm working on some anchor testing)
(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")
"Well, I just climb up to them."
by Joe Brown, English rock climber
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Last edited by pdqaltair; 06-27-2015 at 03:39 PM.