[TowerTalk] rigging for lifting a heavy mast?

[Charlie Gallo]

On 11/6/2013 Rob Katz wrote:

> I'm going to be installing a 20' heavy steel mast in my tower (a
> Trylon 72' self-supporting tower).  I will be renting a crane to
> lift the mast and drop it from above.  What kind of rigging do I use
> on the mast so it can be lifted up vertically, without the sling
> slipping up off the top of the mast?

> Thanks and 73,
>    Rob  K4OV


There are a few different ways

Probably the way your crane operator will feel the most comfortable is a loop sling setup in a "choker" configuration
http://www.wisc-online.com/objects/MTL2702/chk1.gif

IF you insist on using knots, DO NOT use polypropylene rope (the yellow stuff) - too slick, in fact, this is a great place where manilla still works, or modern climbing ropes

You tie what is called a "constrictor hitch" (similar to a clove hitch, but it isn't)

http://en.wikipedia.org/wiki/Constrictor_knot

at the balance point, and then a Marline hitch - which is basically a half hitch, but with the ENTRY of the hitch against the item being lifted

YOU CAN do just the clove hitch with a 1/2 hitch, not QUITE as strong, but arborists and a lot of riggers use them

http://www.youtube.com/watch?v=QPVd1oZvEFs

 

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-- 
Charlie
www.baysidephoto.com
www.thegallos.com