Cow's Hitch W/Stopper Knots For UL setup

[Mountainfitter]

I think the Amsteel Blue is pushing the limits as it is.. From what I understand, the 7/64" Amsteel has a rating of 1600lbs. The overhand stopper knot I am using is rated at 80%???? Given the non life threating nature of sleeping in a hammock... I think 20% of rated usage or the 5x factor as knotty said is more then fine.. This would give a rating around 256 lbs...

[opie]

Opie - Don't you think Dynaglide is too risky for Mountainfitter's approach? It has a rating of 1000# which gives it a safe working load of 200# when using a 5x safety factor (the minimum recommended). Mountainfitter is tying stopper knots every 12". Odds are the knots are reducing the line's rating by 40% to 600#. Now the safe working load is only 120#.

Yes.

My point was stay with a whoopie and use dynaglide. If your goal is to shave weight. Or go even lighter and make a UCR from the dynaglide.

[Knotty]

I think the Amsteel Blue is pushing the limits as it is.. From what I understand, the 7/64" Amsteel has a rating of 1600lbs. The overhand stopper knot I am using is rated at 80%???? Given the non life threating nature of sleeping in a hammock... I think 20% of rated usage or the 5x factor as knotty said is more then fine.. This would give a rating around 256 lbs...

Jumping up to the 1/8" Amsteel would provide an even greater safety margin but you'd have to calculate if it's worth the weight.

Yes.

My point was stay with a whoopie and use dynaglide. If your goal is to shave weight. Or go even lighter and make a UCR from the dynaglide.

Cool. Just wanted to make sure people didn't try something dangerous.

[Albert Skye]

The overhand stopper knot I am using is rated at 80%????

More likely 50-60% for HMPE cordage. Nylon has very high strength efficiency with knots and it appears that most knot testing is done with nylon cordage, but as one can clearly see, different materials give different results.

Technically, the cow hitch refers to a girth hitch with only one leg loaded (i.e., when both legs/ends are loaded, it's a girth hitch).

Regarding lightweight suspension: I also use short loops on my hammock attachments. Each loop attaches by girth hitch to a toggle on the continuous suspension line. These toggles (at least 8 times the diameter of the cordage) remain adjustable and are held in place by clove hitch (or constrictor if slippage occurs).

[BBQDad]

I feel that the rope will and does damage the bark, and over time the tree will show damage. We use straps for the tree's protection, and to keep the park rangers from frowning on the hammock community.

Ditto, Gargoyle---especially (MY OPINION) if the tree's bark has been wet, perhaps due to prolonged rain or high humidity, or if one is hanging on trees that possess naturally softer or thinner bark; sycamores come to mind. Further, damage to the tree's outer bark __might__ allow infection and/or infestation to gain a foothold.

The damage might not be immediately apparent.

Leave No Trace


DISCLAIMER: I am not a trained forester; however...

GIVEN:

The middle of a rope sags to a point 4 ft. lower than the ends of the rope.
A weight of 100 lbs. is suspended from the center of the rope.
The distances from the ends of the rope to the point on the rope at which the weight is suspended are measured at 10 ft. each.
The rope is assumed to be of negligible weight.

The force in each of the two sections of the rope will be 125 lbs.

The rope's ends are tied around two trees, each 6 inches in diameter.

The rope touches one-half of each tree's circumference; there is essentially no contact with the sides of the trees facing each other.

If rope ___7/64 inch___ in diameter is used, then the pressure against the bark of the trees is ___almost 500 Pounds per Square Inch___. (ASSUMPTION: The rope flattens slightly so that one-fourth of the rope's circumference presses against the tree.)

If straps ___2 inches___ wide are used, then the pressure against the bark of the trees is ___almost 7 Pounds per Square Inch___.

Weights of 200 lbs. and 300 lbs. would, respectively, double and triple those estimates.

_________________________________

MY FEELING: I am more comfortable asking trees to accept a pressure of 7, or 14, or even 21 PSI than pressures of 500 PSI, or 1,000 PSI, or 1,500 PSI.

MY BELIEF: Straps would produce much less abrasion in the event of movement of the load.

MY BELIEF: Trees change slowly. Damage to a tree due to external pressure might not be evident for hours, days, or perhaps even months.


MY OPINIONS:

Straps do not cost very much.

Straps do not weigh very much. Their presence in the pack will not hinder the activities of anyone capable of hiking more than ten feet.

Straps offer two benefits:

1) In the short run, straps help ensure that we will not harm trees.

2) In the long run, straps help ensure that we will not arouse the ire of those whose job it is to make the rules regarding what may and what may not be done in our publicly-owned parks and forests.

I vote for the use of straps in all cases.

Leave No Trace.

[Albert Skye]

I also use webbing tree slings to avoid damaging trees.

I prefer to use separate tree slings anyway, both to reduce abrasion to the suspension line and to keep it clean (avoiding sap, algae, &c.).

[Alter Id]

I have been trying to come up with the lightest weight hammock setup possible. The only thing holding me back has been a suspension system. A while back I built my own whoopie sling and it's worked great but around the tree was always the variable especially since I didn't want to add the extra weight of carabiners..

The loop shackle nacra533 brought to our attention would be a UL alternative to the biners. Here's the link http://www.hammockforums.net/forum/s...t=loop+shackle