(This is clean-up of a previous post)
Is Amsteel the same thing than Amsteel Blue?
They are not the same thing, but are often confused. What is being sold by cottage vendors today is usually Amsteel Blue, even when they don't always call it that.
Does Amsteel Blue have 8 or 12 strands?
The 7/64 commonly used for whoopie slings, has only eight strands, but diameters beyond that have twelve. The Samson documentation invariably lists Amsteel Blue as a Class II, 12-strand product, but that documentation often does not include the 7/64 size.
What is high modulus?
Amsteel is defined by Samson as a “high-modulus polyethylene” rope. The high-modulus part means that Amsteel has “low elasticity elongation” or in other words, it doesn’t stretch much. However, this also means that this type of rope doesn’t like to be shock-loaded, so ease into the hammock! Safe working loads do not apply to shock loading.
What is the safe working load (SWL) of Amsteel 7/64?
Working load (WL) is the load that a rope is subjected to during normal use. WLs are based on a percentage of the breaking strength (aka tensile strength) of new and unused rope. They are calculated by dividing the rope’s breaking strength (BS) by a safety factor (SF).
The breaking strength of Amsteel Blue 7/64 is 1600 pounds. Samson recommends that maximum workloads should be 1/5th, or 20% of the quoted breaking strength (safety factor = 5), and recommends a higher safety factor for uses that involve “life or limb.”
Here is the weight that a typical 7/64 Amsteel Blue whoopie sling is rated to support, using the minimum safety factor recommended by Samson:
SWL = BS / SF = 1600 / 5 = 320 lbs
What size bury for Amsteel 7/64?
Samson specifies that a fid is equal to the diameter of the rope x 21, and that an effective bury for Class 2 rope should be three and a half fids. The diameter of Amsteel 7/64 is 0.11 inches, so for this rope, one fid is equal to 2.31 inches. So the recommended bury would be about 8 inches.
Bury = fid x 3.5 = 2.31 x 3.5 = 8.01 inches
The length of the bury depends on the diameter of the rope. Counter-intuitively, the smaller the diameter of the rope, the shorter the bury needs to be. For example, a whoopie made with 1.75 mm Zing-it would only need five inches of bury.
To stitch or not to stitch?
The eye of the whoopie sling is usually made with a locked Brummell, which usually does not require stitching. The eye made in some variations of the “utility constrictor rope" (UCR), does require lock stitches.
Why use splicing instead of knots?
Knots degrade the strength of the rope up to fifty percent. A good splice should not reduce rope strength by more than ten percent.
Resources:
Samson Rope User Manual
http://www.samsonrope.com/Documents/...Manual_WEB.pdf
Amsteel Blue as Class 2 rope (see page 8)
http://www.samsonropecatalogs.com/home/100239.pdf
Splicing Main Page (See Class II, 12-strand)
http://www.samsonrope.com/Pages/SpliceInstructions.aspx
Eye Splice PDF
http://www.samsonrope.com/Documents/...Splice_WEB.pdf
Eye Splice Video
https://www.youtube.com/watch?v=EjR4...ature=youtu.be
Whoopie Sling PDF
http://www.samsonrope.com/Documents/...l-Blue_WEB.pdf
Other Splicing Tutorials
http://www.yalecordage.com/pdf/yale_backsplice.pdf
http://www.machovec.com/rope/splicing/splicing.htm
https://www.youtube.com/watch?v=gRuiTrR4KQA
https://www.youtube.com/watch?v=KtJGTgpv4dc
Utility Constrictor Rope (UCR) Tutorials
https://www.hammockforums.net/forum/...ty+constrictor
https://www.youtube.com/watch?v=vbkojiRcEf0
https://www.youtube.com/watch?v=Yw6P3pHt8KI (5:26)
https://www.youtube.com/watch?v=17_uXaEfZ9w
https://www.youtube.com/watch?v=aBiGD--SOFg
https://www.youtube.com/watch?v=Ch-bqE7OQZw
Terminology
http://www.ropecord.com/new/terminology.php#D
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