bolt snaps and cave line

[tbone1004]

He may be thinking of polyester....

Polyester/Dacron has a higher specific gravity than nylon... Polypropylene and dyneema float, but I don't think I've ever seen them used on spools/reels. PP would be an awful choice and dyneema is too expensive.

 

[Wibble]

A few years ago, not having easy access to “real“ cave line, I bought the closest thing I could find at Home Depot. Mine was yellow, but it looks very similar to this:

https://www.homedepot.com/p/Everbilt-18-x-250-ft-Nylon-Braided-Mason-Twine-Pink-73296/206094361

It worked OK, except for one thing: the line was quite slippery. It was very easy for knots to become loose. I lost a couple of things including a $100 light because the knot came undone. To stop that, I had to get in the habit of using a drop of super glue on the knot: just melting and mushrooming the knot did not work for long . In addition, the relatively light #18 weight meant it frayed relatively easily as well, so frequently used equipment had to have the line replaced from time to time.

I ended up buying a 1 pound spool of #24 dive line from Piranha Dive Manufacturing. The finish on the line was not nearly as slippery, and so far I have not had a problem with the knots loosening or fraying. I haven’t been using it for an extended period, so in my mind the jury is still out about whether this is a 100% solution or not, but I do know that it has been an improvement. If I had no line at all, I would try to skip the HD line and get line more like the Piranha line.

Melt the ends of the knot with a lighter. Lick your finger and squish the melted blob together (or use the lighter if you don't like burned fingers!)

Some line is complete crap. Bought some cheap 2mm line which was utterly useless for knots. Even when melted it fell apart. It's generally better to pay for a bit of quality.

 

[Divin'Papaw]

I just bought 1000' of this to replace the line on my two reels and two primary spools. Looking forward to using it!

DGX Hi-Viz Blaze Orange Dacron Line Loaded on Bulk Spools

 

[tursiops]

Polyester/Dacron has a higher specific gravity than nylon... Polypropylene and dyneema float, but I don't think I've ever seen them used on spools/reels. PP would be an awful choice and dyneema is too expensive.

LOL. I was thinking polypropylene, wrote polyester. I have big (like 12 inch) spools of polypropylene I use for S&R classes. If floats up off the bottom, which is nice.

 

[Raphus]

Polyester/Dacron has a higher specific gravity than nylon... Polypropylene and dyneema float, but I don't think I've ever seen them used on spools/reels. PP would be an awful choice and dyneema is too expensive.

I am not sure which material was used, but I had line that did float, it was a total mess. . Probably not nylon.

So nylon is the best and only choice for cave line?
Thanks for the info.
I just bought 200m of cave line, after I had the cheap floating line and never thought about it again.
But it's good to know.

 

[rsingler]

So nylon is the best and only choice for cave line?

As noted above, there's also Dacron. I, too am waiting on a 1000' spool from DGX. I bought it because they suggested it's stronger than #24 but smaller, so I can get more on a wreck reel than I could with #36. We'll see if it's more snarl-prone.

 

[tbone1004]

I am not sure which material was used, but I had line that did float, it was a total mess. . Probably not nylon.

So nylon is the best and only choice for cave line?
Thanks for the info.
I just bought 200m of cave line, after I had the cheap floating line and never thought about it again.
But it's good to know.

It depends... If I were running permanent line in a cave, I would prefer polyester, but my reels are all nylon because it stretches a bit

As noted above, there's also Dacron. I, too am waiting on a 1000' spool from DGX. I bought it because they suggested it's stronger than #24 but smaller, so I can get more on a wreck reel than I could with #36. We'll see if it's more snarl-prone.

Dacron=trade name for polyester. It does not stretch and is kind of annoying for cave line, fine for reels.

 

[rsingler]

annoying for cave line

Because it doesn't stretch? Sorry, not a caver.
My biggest concern for wreck is abrasion resistance. Any comments there for polyester?

 

[tbone1004]

Because it doesn't stretch? Sorry, not a caver.
My biggest concern for wreck is abrasion resistance. Any comments there for polyester?

nylon trumps PET for abrasion and the lack of stretch is a bit annoying in a cave though not necessarily a deal breaker.

 

[tmassey]

Because it doesn't stretch? Sorry, not a caver.
My biggest concern for wreck is abrasion resistance. Any comments there for polyester?

When you are connecting one permanently installed line to another with a temporary (“jump”) line, the way you do it is to lock off your spool or reel just short of the destination, maybe by a foot or so. You then stretch the line the last few inches before you wrap around it and clip back onto your temporary line.

You do this to keep the jump nice and straight with a little bit of tension on everything so nothing moves. Otherwise, other divers coming through can make your once-clean temporary line become a nasty mess. Let alone in a no viz situation, where having a loose line wiggling around randomly could be a real danger.

That’s one of the skills I’m still working on as a baby Cave Diver: exactly when to lock off my real or spool to leave just the right gap to create just the right amount of tension so that everything is kept clean and snug, without needlessly yanking on the permanent lines or causing my temporary line to slide up or down the permanent line because of too much tension. (Which is why you want your temporary line to come at the permanent line at a 90° angle, so it won’t slide under tension.)

Running lines in a cave is an art.