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I might point out that the strength derived from cave line is not from the knot but rather from the successive wraps you use to join the two items. The knot is there merely to keep the wraps from unraveling. And if you overlaying wraps (hitches) it keeps the strain off the knot. Thats why a simple square knot is sufficient (in conjunction with melting the tails) for your reel line attachments. When you are using cave line on rubber tubing you have the additional benefit of the rubber keeping a constant strain on the wraps, which keeps everything nice and tight. I know these kind of details are causing certain people to run screaming out of the room, but jeeze guys, the major topics have pretty much been beat to death. The only thing left is details and refinements. So sit back and chill out. Jim Sender: Patricia Disler Date: 7/1/98 12:14 PM >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 > >> > > ------------------------------------------------------------------- Learn About Trimix at http://www.cisatlantic.com/trimix/trimix.html -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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