Jon Line

Can any one explain how to use a spool or reel as opposed to a Jon line, especially in a current while hanging on a downline/anchor line?

Thanks in advance
BOB L

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Permalink Reply by kevrumbo on October 24, 2009 at 3:01pm

Richard I agree that hanging on the upline being blown around like a kite is very stressful, especially bunched up with your team trying to do a deco gas switch. But the alternative may be a long wait on the surface for a chase boat pick-up, with potential sea state and weather conditions along with boat traffic complicating recovery. There are other "unique" hazards elsewhere in the world as well: The captain of my liveaboard (2006) in the South China Sea counseled me after I was blown off the upline in ripping current. He discourages drifting deco not only because of container ship traffic in the shipping lanes to Singapore; he also warns that that dinghy you see with the crew holding AK-47's coming to your apparent rescue may not be the Indonesian Navy at all --but a boatload full of pirates curious about you & your orange SMB's in the water. . . (Not sure if he was kidding or not but he made his point about Singapore, the busiest container ship port in the world).

Richard said:

Fellas, knock yourselves out, hang on the anchor line as much as you wish. The reality up here for deco dives its either impossible (even a jon line would be awful so you must drift) or its not necessary to actually attach yourself to the line (grab it off and on, or scooter up +drift back a bit). Certainly in a recreational situation you can just modify your stops to stagger along the upline, no big deal. While I haven't been diving "everywhere" the same principles do apply.

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Permalink Reply by robert lucas on October 24, 2009 at 4:36pm

Man, And I'm worried about fish hooks and rain.

kevrumbo said:

Richard I agree that hanging on the upline being blown around like a kite is very stressful, especially bunched up with your team trying to do a deco gas switch. But the alternative may be a long wait on the surface for a chase boat pick-up, with potential sea state and weather conditions along with boat traffic complicating recovery. There are other "unique" hazards elsewhere in the world as well: The captain of my liveaboard (2006) in the South China Sea counseled me after I was blown off the upline in ripping current. He discourages drifting deco not only because of container ship traffic in the shipping lanes to Singapore; he also warns that that dinghy you see with the crew holding AK-47's coming to your apparent rescue may not be the Indonesian Navy at all --but a boatload full of pirates curious about you & your orange SMB's in the water. . . (Not sure if he was kidding or not but he made his point about Singapore, the busiest container ship port in the world).

Richard said:
Fellas, knock yourselves out, hang on the anchor line as much as you wish. The reality up here for deco dives its either impossible (even a jon line would be awful so you must drift) or its not necessary to actually attach yourself to the line (grab it off and on, or scooter up +drift back a bit). Certainly in a recreational situation you can just modify your stops to stagger along the upline, no big deal. While I haven't been diving "everywhere" the same principles do apply.

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Permalink Reply by Lynne Flaherty on October 24, 2009 at 9:29pm

You know, as I recall, there was an extremely long and sometimes acrimonious discussion on the Quest list a number of years ago about this. What I took away from reading the whole thing was that a) conditions vary in different locations and b) the dive plan should take into consideration those conditions. It isn't always possible to drift deco. Where we were in the Red Sea, for example, if you drifted, you drifted into wide open water with swells that would make it very difficult to see a bag, and the boat, having multiple teams in the water, couldn't chase everybody at once. If you're in Puget Sound with scooters, you can choose another option. Monterey in fog has other considerations. You can't lay down a single law and sneer at anybody who doesn't follow it; that's how Joe and Delia got into trouble in the first place.

There was an East Coast fatality a couple of years ago that involved a well trained and very experienced DIR diver with his usual teammate -- cause of death was judged gas embolism, and the posited cause was hanging onto a jerking anchor line. Seems to me a jon line is preferable to that.

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Permalink Reply by Marc Blackwood on October 25, 2009 at 4:13pm

A scooter may be a good option, but it's not infallible. If I have a scooter and the current isn't too strong to kick against, I'll opt for the scooter.

But if I can't kick against the current, I'll opt for a jon line. I suspect that my 3/8" rope will break with much less frequency than my scooter will fail, run out of batteries, etc..

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Permalink Reply by Maciej Arkuszewski on October 25, 2009 at 6:24pm

If I absolutely don't want to loose the line I would opt for team on scooters. There's no backup for failed jon line.

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Permalink Reply by Marc Blackwood on October 25, 2009 at 6:34pm

Maciej Arkuszewski said:

If I absolutely don't want to loose the line I would opt for team on scooters. There's no backup for failed jon line.

What's the backup for a failed scooter when you can't kick against the current?

I suppose your team mates may have a scooter strong enough to drop back and pull two divers back to the upline, but that won't necessarily be the case. Also, I'm thinking batteries are the most likely failure, and teams diving similar scooters will have similar burn times.

I opt towards a robust mechanical solution.

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Permalink Reply by kevrumbo on October 25, 2009 at 7:07pm

And how do you do a deco gas switch while keeping station in strong current with a scooter near the upline/anchorline? You lose sight of the upline while you're identifying your deco bottles on the switch --well, you've now got an inadvertent drifting deco scenario (and that's what happened to me above, South China Sea 2006 after a dive on battleship HMS Repulse).

Pitch-down and secure the scooter trigger; loop the nose leash around the upline/anchorline and clip back on the D-ring; stay clipped-on connected to your scooter's towline --and you now have a jonline using the scooter. You're hands free to do you your deco bottle switch. . .

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Permalink Reply by Maciej Arkuszewski on October 26, 2009 at 8:43am

Obviously you plan and take enough juice to complete the whole deco on scooter running with someone in tow. If your scooter is running at capacity just to stay on a line it's no different from jon line. You have to have extra horsepower.

Doing a bottle switch one handed is not terribly hard skill to learn, but if you have opportunity to clip yourself off for a bottle switch or whole deco and make your life easier - great. Scooter is there to use when this option is not available. Keep in mind that you will have whole team switching at the same time.

So: use everything that's available to make it easier, but have a viable contingency with you. Hooking with jon line and crossing my fingers that nothing snaps is not an option I like. Having a scooter that's too weak - likewise. Having a scooter with not enough juice - not good as well.

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Permalink Reply by Marc Blackwood on October 26, 2009 at 9:10am

"Enough juice" is hardly a backup plan, and it doesn't account for current too strong for your scooter. I've watched Andy trigger up to 5 on my Sierra and not make any headway. No way could it have pulled two of us back to the line.

Worst case scenario, if your scooter fails, you're drifting deco, and if your jon line fails, you're drifting deco. Since the consequences of failure are the same, I have to look at the likelihood of failure. One the one hand I have a scooter with (at least) the following failure points: batteries, electronics, clips, springs, o-rings, motor.

On the other hand I have a piece of nylon rope with a rated tensile strength of 2,700 pounds.

Personally, I'll have that jon line in my pocket for any dive where I don't want to drift deco. If conditions are such that I'm comfortable scootering deco, so be it. If not, I can always attach myself to the line.

(Or maybe there will be a convenient lobster trap nearby :P)

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Permalink Reply by Maciej Arkuszewski on October 26, 2009 at 10:43am

Towing your buddy on a scooter is a viable contingency in a current (current 1) to stiff to swim back. It's not in a current (current 2) to stiff to motor back. current 1 current 2
There's no contingency for broken jon line (which also involves clumsy hands). That's true both in current 1 and current 2.
I believe there was also a sentence: "You have to have extra horsepower". Let me expand a bit: "enough horse power on your scooter to tow you and your buddy in tow to the upline if you happen to drift away a bit".

Also seems that both of you missed it: I'm not advocating NOT using a jon line when you have a scooter - if you have that option, go for it, just don't assume it will be available.

Diving in vis or current which precludes you from coming back to the line if you happen to loose it for split second is perhaps not a best idea of a dive if drift = harm. Regardless of you using jon lines or scooters or other contraptions. I would walk away from plan like that.

If drift is acceptable, it might be better to explore ways of making it a plan A, rather than making concessions for convenience of boat operator which result in drift option being much more harmful and CF.