Dave(Offline)

heya,

was casually chatting with some club friends about using a figure of 8 knot vs figure of 9 this weekend and then just saw someone else mention it randomly on here so thought i'd see what the general opinion and reasoning was???

as far as i know the only real advantage of the figure of 9 is that it's less likely to come undone (although obviously that means it's harder to take out if you do want to remove it) but i think one of them causes less stress on the rope aswell (can't remember which one though??????)

thanks,
Dave

davy (Online)

what do you want to use it for?

In dry caving we sometimes use the figure 9, but mostly the figure 8.
figure 9 is the stronger knot though and easier to untie, but uses more rope.

For diving I limit myself to square knots( eq. boltsnaps), figure 8(eq. the woody), bowline(eq. loop in spool/reel) and the fishermans knot

lizardland(Offline)

Figure 9 is the one which allegedly causes the least amount of stress. It is meant for use in thinner ropes and is said to be less likely to come undone. On the other hand, it's a lot slower to tie if you're doing a rewoven knot e.g. tying into a fixed anchor, and it uses more rope if you're using thicker ropes.

A figure 8 with a stopper knot is still a very reliable knot. I tend to avoid reef knots for anything important, it can end up as a slip knot if you catch it the wrong way.

__________________
Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you?

www.westons-cider.co.uk

The Lot isn't the only place to dive: http://www.lulu.com/content/613554

Diablo(Offline)

"A figure 8 with a stopper knot is still a very reliable knot."

Yep and very easy to tie. I use this knot all the time, when climbing with my loved ones (wife and kids).

"I tend to avoid reef knots for anything important, it can end up as a slip knot if you catch it the wrong way."

Perhaps it really is good enough for the wife after all.

Dave [/quote]

zoglet(Offline)

Hi Dave

I recall a long tintynet post where a bunch of peeps were arguing which knot should be used for the loop on your DSMB line.

The argument was loosely that the figure of 9 puts less strain on the line itself and is therefore a stronger knot and easier to untie. Most knots reduce the rated strength of the line by a certain amount, some less than others. The figure of eight reduces line strength more than the figure of nine (55/40 vs 75/55 % on normal/abnormal load) so some argued that the figure of nine was the only knot that should be used.

My argument to the contrary would be (as a non-DIR non knot specialist so pleeeez don't flame me everyone, lol) the principle of a knot is that it does the job required of it (stopper, joiner, loop etc), can be tied and untied quickly and easily and doesn't adversely impact the strength of the rope.

I would have thought that for the purposes of a DSMB loop even reducing the strength of your cave line to 55% is irrelevent on a line rated to 100kg with nothing but free floating sock of air on the end of it and therefore the simpler knot to tie is fit for purpose.

Either way it seemed an amusing topic at the time for a bunch of people to get hung up over so I'm embarassed to have exhumed a nasty smelling well flogged horse carcass for a second round. Then again that's what forums are all about.

"Seconds Out"!

Dave(Offline)

heya,
this all came up because we had an inpromptue knot tying session (living life on the edge i know ) and it was just a case of what knots people knew.
for climbing and dry caving i use doubled up figure 8s (with stopper knots) but figure 9 is what some people end up tying by mistake when trying for a figure 8 and i thought i'd been told it put less stress points on the rope and was more secure, so wondered whether that was a better knot for DSMBs.....
but think zoglet's right, aslong as it does the job that's all that matters

cheers,
Dave