Any pics or videos? What rope.... Oplux?
Oplux and TRC.
I don't have a video link and can't take pics now. There was another thread I'll try to find. Someone else might find it.
Unless you can look at the Cruzr adjustable bridge you have in hand and know how to make it with other rope, then I wouldn't mess with it yet. If you haven't tied your own loops and such, do not start with one of the most important pieces of gear you have. This is something I spent probably 40 hours on tying and doing research before I did anything for life support.
Having said that, on the right side (if you're a rightie), you just tie a loop (figure 8 on a bight) in the end of Oplux and then put the end of the rope through that loop (with bridge trapped in there) 3 times and that forms a 6 wrap prusik. The trick is to make the loop long enough but not too long. Leave appropriate tag end. I tuck the tag end back under the loop to keep it out of the way. Make the loop too big and then adjust to make smaller after the prusik is tied. I use the follow through method which is more complicated but works better and doesn't twist your rope up or waste as much.
The left side is more complicated. You tie loop of appropriate size using TRC and the loop is formed with double fishermen's knots. Once you have your loop, then you do the same wrap with it as you did on the right side to form the 6 wrap prusik, but this time using the TRC. You will have a remainder of TRC hanging off the top and you use that remaining loop to tie a wrap prusik onto the Oplux. I do not do it like this (tying the loop first and then twisting it all up). I trace the TRC how I'd like it and then once the two ends of the TRC touch, I tie the double fishermen's knots as the last step.
The double fishermen's knots can be tied incorrectly and be put into a configuration where they will slip/fail. This is the most likely point of failure for this system. When you bring your tag end under the wraps you must cross over the line that you used to start the knot (I do not know the technical term for that) and then go through all wraps in a way where they maximally constrict that end of the line.
I would not attempt this until I was 100% sure I knew how to form a loop (or join 2 lines) using double fishermen's knots, and had used them and knew they would hold.
And also had figured out how I could tie them wrong (and done that on purpose) so I could detect it. After I tie them, I still open them up a bit one last time and mentally trace the line and know that I'm good. And was also familiar with figure 8 and prusiks. Sorry if I am sounding too basic here, but I don't want to make any assumptions.
Alternatively, you can buy a sewn loop that replaces the TRC, and then you don't have to tie the double fishies. But you then have less control over final length.
I tie it like this but I give it one extra wrap before finishing up, so it looks like a longer barrel. I'm not sure why I started that, probably a carry over from scaffold knots, which are very similar. But it should not make it less safe.
The Double Fisherman's or Grapevine Bend consists of two strangle knots (like double overhand knots) each tied round the other standing end.
www.animatedknots.com
EDIT: I just realized that I've been tying a triple fisherman's knot. I think I knew that at one time, but started calling it a double fishie with extra wrap.
Learn to tie the Triple Fisherman’s Knot for fishing. See detailed instructions, pictures, tutorials, and videos for the Triple Fisherman’s Knot, also known as Triple Fisherman’s Bend.
www.knotsforfishing.com
