The Jon Line...

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atedeschi

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Narc'ed TV - Episode 5: "The Jon Line"

Please check out our new episode, hope you enjoy. Be sure to subscribe to our YouTube or our podcast on iTunes to get the latest updates


Episode%2B05.png
 
For me, the main advantage of a Jon line is to isolate the jerking of the anchor line in sloppy seas -- a common issue on wreaks like the Doria. A typical anchor line in heavy seas has a 3 to 5:1 scope so is more horizontal than vertical. Hanging onto the line directly can yank your arm out of its socket everytime the bow lurches in the swell.

I also find using 1"/25mm soft webbing is more tangle resistant than line. Same with Reef Hooks.
 
unless im diving in strong current on a regular basis i wouldn't use one - just another piece of gear to fiddle with
 
For me, the main advantage of a Jon line is to isolate the jerking of the anchor line in sloppy seas -- a common issue on wreaks like the Doria. A typical anchor line in heavy seas has a 3 to 5:1 scope so is more horizontal than vertical. Hanging onto the line directly can yank your arm out of its socket everytime the bow lurches in the swell.

I also find using 1"/25mm soft webbing is more tangle resistant than line. Same with Reef Hooks.

I did my first boat dive in dec while on a cruise in ft marteen. The only line we had was the mooring line and I was experiencing exactly what your talking about. I was being tossed all around and pulled slightly under when the boat would rock. We had pretty rough seas that day too as out of 14 people diving 13 got sick. My arm was killing me for a few days after this.
 
For me, the main advantage of a Jon line is to isolate the jerking of the anchor line in sloppy seas -- a common issue on wreaks like the Doria. A typical anchor line in heavy seas has a 3 to 5:1 scope so is more horizontal than vertical. Hanging onto the line directly can yank your arm out of its socket everytime the bow lurches in the swell.

I also find using 1"/25mm soft webbing is more tangle resistant than line. Same with Reef Hooks.

Yes exactly not having to strain well performing your decompression possibly leading to a hit in s joint is definitely one of the advantages to using the jon line. The webbing works well for me paracord is always around and stows nicely. Also the reef hook that I recall thinking of is kinda big from what I recall and can get caught in your pocket with the other contents.
 
unless im diving in strong current on a regular basis i wouldn't use one - just another piece of gear to fiddle with

If your diving NE wrecks or any sites where you are required to ascend a fixed line it’s a critical piece of equipment used on everydive. Even if there is no current it’s makes your decompression stops much more relaxing by being able to clip in put alittle air in your suit and just close your eyes and relax. Also it helps with safety in the event you had a tox issue, you won’t disappear to the bottom with no one noticing.
 
I carry one for NE wreck diving. I use it for two reasons. One is to get some distance from the line when it's jerking up and down. The other is to get some distance from the line when 8 people are already trying to hold a 20' stop on it. If neither is a problem, I just hold the line. I probably hold the line about half the time and use the jon line the other half.
 
I carry one for NE wreck diving. I use it for two reasons. One is to get some distance from the line when it's jerking up and down. The other is to get some distance from the line when 8 people are already trying to hold a 20' stop on it. If neither is a problem, I just hold the line. I probably hold the line about half the time and use the jon line the other half.

Great points, curious what length of hangs you have? Anything longer then 15 minutes you should really consider using it all the time just to reduce risk of possibly hit in wrist or elbow from the strain.
 
Great points, curious what length of hangs you have? Anything longer then 15 minutes you should really consider using it all the time just to reduce risk of possibly hit in wrist or elbow from the strain.

Depends. Most of the time, off the NJ boats, probably 30 minutes or so. But if there is any strain I break out the jon line. If the current is light (or nonexistent) the upline can just go back and forth inside my fingers...
 
My hangs this season have been averaging around 40 minutes, so I've been just using a spool loaded with cave line as a jon line. It really does make the hang more manageable when the anchor line's bouncing up and down. The spool works well, but it can be a bit fiddly getting it off the the anchor line when it's bouncing everywhere, so I'm considering getting some 1" webbing and putting a garvin hook at the end. What's a good length to make the line?
 
https://www.shearwater.com/products/perdix-ai/

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