Sherrill Backbone
- Thread starter wyoclimber
- Start date
evo
Been here much more than a while
- Location
- My Island, WA
I get your point, but with a 10:1 or a 5:1 your are still way into the safe range with knots. If your worried about a bowline parting the rope, your pushing the limits. I trust knots more than gear.
I love knots,I'm like a knot fkn wizard on the job,i like my splices more,very gratifying.
When rigging,of course taking 10:1 ratio into consideration,I decide which setup I'm using according to how much weight im loading and to factor in the strength loss of knots,thats gonna require bulky rope more often than not. evo,what ropes are you lowering with?(dia./model)
When rigging,of course taking 10:1 ratio into consideration,I decide which setup I'm using according to how much weight im loading and to factor in the strength loss of knots,thats gonna require bulky rope more often than not. evo,what ropes are you lowering with?(dia./model)
I have 1/2" rigging line 8000# MBS
10:1 safety factor says the I'm good for 800#
If I lose 50% I get 400#
If I use that as a pull line with a 200# guy on a 3:1 that's 600# of pull
That's 1 1/2x my swl
I've used this rope comfortably for much more than that. I run 5:1 safety factor and I've seen work that says stilson, fisherman hold 80% rope strength and bowline I think 60 or 70%. I feel ok using those #'s
For what it's worth...http://www.bethandevans.com/load.htm
evo
Been here much more than a while
- Location
- My Island, WA
7/16 kernmantle (mostly as a pull rope, or zip)
1/2 DB
1/2 16 strand
1/2" 12 strand
5/8 DB
3/4 DB
1" 3 strand
1 1/4 (?) DB (only used as a guy on a gin in a mini highlead)
Yea the 10:1 factor has alot to do with cycles to failure,and the knots breaking point is well out of range for breaking as long as you stay in your swl ratio ,even if it's 5:1,you shouldn't have to worry at all as long as your tying right lol,%20 mbs is your swll and the knot retains %40-%70 line strength ,I don't see it ever being an issue.
Correct different knots have different strengths so you have to reduce knot loss from straight swl.
So my 1/2" db is:
MBS 8000 lbs
5:1 safety factor =1600 lbs
Stilson holds 80% strength= 1280 lbs
So my wll (to be more accurate) is 1280 lbs
Hope that helps
Last edited:
I finally got off work!!
kevin,we have gone over the swll ratio's and why in that other thread, Im confident in my swl's,i go by a 10:1,and use splices.
So here is the "standardized" recommendation.
mbs<10:1 swl/2(safe working load divided by 2) to account for rope wear and KNOTS.
I'm not making this stuff up I swear.
kevin,we have gone over the swll ratio's and why in that other thread, Im confident in my swl's,i go by a 10:1,and use splices.
So here is the "standardized" recommendation.
mbs<10:1 swl/2(safe working load divided by 2) to account for rope wear and KNOTS.
I'm not making this stuff up I swear.
Hitches are definitely stronger than knots
10:1 swl/2 for knot = 5:1 wll knots included. So your standard is the long hand version of mine.
Half of a 10:1 factor is a 5:1 factorYou divide the wll by two,or you cut your wll in half. 10:1 Does not equal a 5:1 in the end. Dealing with ratios,I think You may have the math backwards.when you divide the 10:1,its making it 20:1, I don't know why they word it this way.
Sorry 5:1 knotted =10:1You divide the wll by two,or you cut your wll in half. 10:1 Does not equal a 5:1 in the end. Dealing with ratios,I think You may have the math backwards.when you divide the 10:1,its making it 20:1, I don't know why they word it this way.
