Bunny ears double figure of 8 knot - Stronger or weaker than a standard figure of 8?

[Lawn and Leaf]

As per the title really!

 

It struck me that given the standard knot loses approx 30% of the strength of the rope, and the strength loss is to do with the tightness of the bends (And figure of 8 is good because they aren't tight in the first place), does it not make sense to use a double figure of 8, bunny ears style (see below) To either make the end of the rope closer in strength to the main length, or perhaps even exceed it as It would be doubled up?

 

Figure 8 Double Loop | How to tie the Figure 8 Double Loop | Climbing Knots

 

If I was to use this doubled up knot would it make sense to use each of the loops separately? I suspect using them together would be the better choice, but one could put a shackle on each and use them separately for different ends of the log.

[Tom D]

Under what circumstances, will you be loading your rope to the point where the choice of knot will be critical?

 

I only ask as the factors of safety that we use (or should use) in arb are so generous that the choice of knot ought to be insignificant.

[bob]

the problem with the double knot is been able to load both loops evenly

if one is loaded more the knot distorts

though looks to have wider bend radius

[AHPP]

Absolutely not worth worrying about.

Apologies for the lack of scientific answer you may have been hoping for.

[Rupe]

Thats fine but wont undo after loaded very well. We generally use termination knots that are easy to untie, and as tom D says 10:1 safety is plenty for our rope/knot combos, we do in fact have nearer 20:1 safety for normal use anyway, so the most convenient knot is best rather than a big cumbersome thing!

[atree]

Could you explain what the factor of saftey is, like the 10:1 you mention rupe??

[DrewB]

hey bro, if a ropes breaking point(MBS) is 3800kg then its safe working load(SWL) using 10:1 is 380kg.

i think this is why we use 22kN as a minimum. 2200kg(22kN approx) mbs gives a swl of 220kg-therefore can take 2 climbers plus gear in an emergency situation ie rescue and allows for cycles to failure.i think.

[atree]

Ok,think i know what you mean.Cheers for explaining.

[Justme]

Do any of you use the Fig 9 knot?

 

Its just as easy to tie as the fig 8 but will undo after loading easier.

[Rupe]

Only just noticed this is in rigging and roping section, so for a termination knot on a rigging line this fig 8 is ok but would be very hard to undo.

 

safetyfactors are still 10:1, but not 20:1 like I was suggesting a climbing rope is when used normally with one person. (Like drew says the 10:1 allows for rescues scenarios)