1. Guide to Amsteel

(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

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

Utility Constrictor Rope (UCR) Tutorials
https://www.hammockforums.net/forum/...ty+constrictor

Terminology
http://www.ropecord.com/new/terminology.php#D

2. Very nice guide. I made it a sticky

3. Could you please explain why sgtrock says the smaller the rope the longer the bury.

I have trialed 1.9,3,&4mm dyneema rope and can agree with him that the 1.9 kitedyn required more bury than the recommendation on Sampson rope page-200mm instead of 139.65mm.

Another good question would be why do you guys stick with using the name "amsteel".

Amsteel is a brand name.
The product is actually dyneema braided rope SK75,and is made from UltraHighMolecularWeightPolyEthylene.
This product is closely related to plastic milk bottles?????

4. Great information here and all in one place. Thanks! Is this stickied somewhere?

Sent from my SAMSUNG-SM-N900A using Tapatalk

...

Another good question would be why do you guys stick with using the name "amsteel".

Amsteel is a brand name.
The product is actually dyneema braided rope SK75,and is made from UltraHighMolecularWeightPolyEthylene.

...
There are other UHMWPE fibers other than SK75, e.g. SK78.

Samson's Amsteel Blue, Lash-It, and Zing-It are all SK75, as well as many products from other manufacturers. With the exception of Dynaglide from NER and the 1.75 stuff being made for Dutch, I think almost all of the UHMWPE cordage that hangers are using, at least in North America where the majority of the posts come from, are products from Samson.

I do understand that it isn't the case on other continents...

Amsteel (without the "Blue") isn't made in the sizes we typically use and it has become habit to drop the "Blue" when talking about these products because it doesn't add any value in general discussion. It actually adds confusion when talking about red or black or grey Amsteel Blue!

Easier than calling it Dyneema/Spectra I suppose.

6. A number of posts have been removed from this thread because they were off topic. As this is a sticky guide please keep all post on topic.

7. I think this goes here. So if using Amsteel for suspension with 7/64 whoopie sling with 320 lb working load does that mean that a person weighing >320 lbs should go up to 1/8. If I remember my physics the load is shared by both sides so each WS would not see the full load of the person. Making 7/64 sufficient for a person a bit heavier than 320 lbs?

8. Guide to Amsteel

Originally Posted by campacker
I think this goes here. So if using Amsteel for suspension with 7/64 whoopie sling with 320 lb working load does that mean that a person weighing >320 lbs should go up to 1/8. If I remember my physics the load is shared by both sides so each WS would not see the full load of the person. Making 7/64 sufficient for a person a bit heavier than 320 lbs?
I'm no engineer, but the load is probably shared. I would imagine that for most hangers the 7/64" Amsteel is not the weakest link in their hammock system. For example, a many of us use 1500# tree straps. With a 5x safety factor, you are looking at a 300# WLL for the straps, and that is not considering what hardware or knots might do to the rating.

So, if someone is considering going up to 1/8" Amsteel, they should probably go up to 2500# straps and a hammock rated for at least 375#.

Personally, I would feel fine with properly spliced 7/64" Amsteel up to 500#.

HYOH.

9. Originally Posted by Gravity
...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
FWIW, the minimum breaking strength of Amsteel Blue is 1400 lbs while the average breaking strength is 1600 lbs so use whichever you are comfortable with.

More importantly, the typical breaking strength of a whoopie sling is ~80% of the rated strength so using your example...(1600x0.80)/5=256 lbs.

Originally Posted by campacker
I think this goes here. So if using Amsteel for suspension with 7/64 whoopie sling with 320 lb working load does that mean that a person weighing >320 lbs should go up to 1/8. If I remember my physics the load is shared by both sides so each WS would not see the full load of the person. Making 7/64 sufficient for a person a bit heavier than 320 lbs?
Your memory is faulty. At a 30* hang angle, both ends see the full weight placed in the hammock.

http://www.ropebook.com/information/vector-forces

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