Line repair

[LCF]

Well, I'd be very surprised if Danny went over it, because I think every word Danny said in that class is burned into my brain. I still hear his voice when I'm cave diving: "The time to switch to a different kick is BEFORE you hit something!"

[gschaut]

If you feel like learning something fast AND secure enough to trust your life to:

When using a spool to make a repair- first attach the loop to one end of the line to be repaired with a Prussic.

http://www.animatedknots.com/prusik/...matedknots.com

The ONLY difference from tying onto a jump, is that you pass the spool thru the loop of line THREE times. Just like tying into a jump with OCD.


At the other end, tie the spool end of the rope onto the line to be repaired (damaged section to be bridged)
with what sailors call a "rolling hitch" (fire service calls it a "chimney hitch).

http://www.animatedknots.com/rolling...om#midshipmans

It's just a variation of the simple clove hitch. You put TWO loops on the load side of the hitch.

The BEAUTY of the chimney/rolling hitch is that you can Take Up Tension on the line AFTER you tie the knot. You can take the chimney hitch in your hand, slide it up the gold line to increase tension. And when you let it go, It Stays Put!!!.

Both these knots are designed to hold tension in line with the rope they are attached to. So you can use these knots to safely bridge a broken section of gold line.

If you want to, you can use either knot at both ends. But given that all our thumb spools already have a loop on the free end, you can throw a prussic in a few seconds. Fast and Easy.

[et05hk6]

I believe the best knot to use for fixing cave lines should be the Sheetbend. Its main purpose is to lengthen and repair ropes of any dimensions. If you want to feel extra secure (why not?) you can use the double sheetbend: http://en.wikipedia.org/wiki/File:gr...eet_bend_2.jpg.
As you can see this knot is very good for temporarily fix for example damaged main lines of thicker dimensions using a thin jump spool. It's also of course good to fix two thinner lines.

[PfcAJ]

I use the bowline or fishermans knot method(s). Knots that won't come untied if the line goes slack seems pretty important to me. Iirc, the sheet bend can be easily mis-tied, and that version is quite weaker.

[DA Aquamaster]

At the full cave level we were trained to repair line and also to create a gap line repair on both sides of an entanglement before cutting ourselves free - and we did it in total darkness to simulate a total silt out, so it had to be done by feel alone. Simple knots that are easy to tie by feel alone become important in zero viz.

Probably the easiset way is a bowline tied into another bowline. I generally use a fishermans/prusset knot, however.

I wrote a short article that was published in UWS about a year ago about it. I'll look for it and republish it.

I use the bowline or fishermans knot method(s). Knots that won't come untied if the line goes slack seems pretty important to me. Iirc, the sheet bend can be easily mis-tied, and that version is quite weaker.

That's the critical issue with the bowline. It's a great knot to secure a load at the end of a line, but they do not stay tied all that well when not under load, so if the line goes slack at some point you risk having the knot come undone. If the line is moving a bit in flow or is disturbed by a diver it's almost inevitable that it will come untied if the line is slack. A half hitch on the bitter end of the line helps but a double fisherman's knot is more secure.

If the line is long enough to be repaired without a splice and there is enough slack to tie a double fisherman's knot, I'll just do that directly. The double fisherman's knot is the same as a fisherman's knot, just with a second wrap and it's a lot more secure.

However if the line is long enough to be repaired without a splice but snug enough to make tying a double fisherman's knot difficult, my preference is to take a finger spool and tie into one end of the broken line with a French prusik knot using the loop on the spool. Just wrap the loop loosely around the line 3 times, run the finger spool through the remaining loop and snug it up on the line.

I'll then tie into the other end with a blake's hitch, but finishing it with a long loop up through the first two loops rather than with the bitter end of a cut line to avoid having to cut the line off the spool at all. Just clip the spool back on the line to keep the spool from pulling the loop free. The resulting line allows me to bridge the gap and apply the tension needed to get sufficient slack to tie the double fisherman's knot.

Even if you prefer to cut the line off your spool, the blake's hitch is idiot proof to tie as you just make 4 wraps around the line away from you and then come back and run the bitter end back up through the first two wraps on the line. It's easy to remember and works which ever way you wrap, so it's almost impossible to screw up. An added benefit is that you can wrap the line around your finger and the line to ensure lots of space to secure the end or loop to finish the knot, so it's also very easy to tie by feel in a total silt out. Finally, it will also come loose again easily when you want to remove the gap line after the repair just by pulling the knot itself in the direction of the load. And if you decide you really do need a splice in the line, just place a double fisherman's knot on the load side of the knot to keep it from moving and leave it in place as a permanent fix.

[PfcAJ]

News to me about the bowline. 100% of my spools and reels have a bowline on the end of them, and not one has ever loosened (18-24 braided), let alone come untied.

I know they are easy to untie when not under load, but it takes some work to get it loosened up. Perhaps the phenomenon you're describing is at least somewhat dependent on the type of rope/line used to tie the knot? I might just have to change all my knots!

[LiteHedded]

first time I ever repaired a line was in real life. i was never taught it

[FW]

The person I was diving with was making overhand knots, which created a loop, and then tying the new spool into the loop, and the same at the other end. Seemed to work very well, allowed her to get good tension on the line, and wasn't terribly complicated. I hadn't really thought about how I would go about a line repair, if I had to do one, but I now have a good plan.

For an emergency repair, any knot you know how to make will suffice. An old saying, "if you can't tie a knot, tie a lot".

[DA Aquamaster]

For an emergency repair, any knot you know how to make will suffice. An old saying, "if you can't tie a knot, tie a lot".

In our full cave exercise mentioned above (entangled in the line, installing a bridge line, then cutting out of the entanglement) there were three types of outcomes:

1) tying the line before the cut in a manner where adding a couple fisherman's type knots and trimming the ends left a safe and permanent repair,

2) tying the line with any kind of knot to hold the ends together long enough to exit, requiring a permanent fix later, and

3) a pass by the skin of your teeth "never could fix the line but managed to hold on to the exit side and still get out safely" result that left a live diver but a break in the line.

In some regards, however, unless you go back to fix the line immediately, leaving a break (with no one else in the system on that line) may be better than leaving an un-secure "I don't know how to tie knots" mystery knot that could come loose after someone goes past it into the cave later. A bad repair is not as evident as a break and that deceptive quality can make it more dangerous.

One of the take aways from that learning experience was a habit of inspecting any line repair I come across with loose ends left on it very carefully to ensure it was not someone's emergency repair that was never permanently fixed.

[deepdiverbob]

I dont recall that being taught in any level of my cave classes. I seem to recall talking about it, but it was never actually done.