At 11:40 PM 6/30/98 -0700, Mike Wells wrote:
>I don't know how everyone else attaches theirs, but I used a bowline knot 
>to form a loop the size I need in each end of the surgical tubing, and 
>then stretch each end over the mouthpiece.  In my mind, a zip tie is just 
>another snagging point and failure point (also not very comfy if it gets 
>up against your lips).  If you can do it without one, WHY USE IT?  IF YOU 
>DON'T NEED IT, LEAVE IT. 

 A bowline knot is the most secure, safe, strong 
>knot to use for forming a loop in the end of a line.

I would have to argue this statement on two counts.

The first being... A bowline is indeed a good knot for certain
purposes..However it is NOT the most secure, safe, strong knot for forming
a loop in the end of a line...The bowline has an average strength of 76%
the breaking strength of the rope..Or in this case the tubing.
There are more efficient knots...One being the figure eight which has an
average strength of 85% of the breaking strength of the rope...Or the
tubing if you prefer. The figure nine is even stronger..although for most
vertical work...In which case, my butt is on the line...I use the figure
eight backed up with a overhand knot.
Whichever knot you use for life support purposes...It will be stronger if
it is backed up by a overhand knot.

The second being... When you tie two ends of tubing it is not forming a
loop in the end of the line at all...It is more in tune with joining two
ropes together...Or ends of tubing as it may be...So I would suggest using
a double fishermans knot for this purpose. While the DFN has only 75% the
breaking strenght of the rope..or tubing, it is perhaps the most secure
knot for joining two ends together. Notice I say perhaps... 

Also, I would tend to think that whichever knot one would utilize, it would
be far stronger than the tubing itself.

"SILT HAPPENS" JD                                                JEFF DISLER
 SAFE CAVING                                                      NSS 26000
 
>

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