Jon lines

[Braunbehrens]

The question of Jon lines has come up in another thread, so I thought I'd move it here where it is more appropriate.

Some people seem to think that Jon lines are great. Others feel they are dangerous.

I'm hoping that we can have a meaningful discussion here ...

[Doppler]

Braunbehrens once bubbled...
The question of Jon lines has come up in another thread, so I thought I'd move it here where it is more appropriate.

Some people seem to think that Jon lines are great. Others feel they are dangerous.

I'm hoping that we can have a meaningful discussion here ...

Don't recall anyone saying: "Jon lines are great."

The last post on the topic said this: " Jon lines are a useful tool and worth learning how to use, and in adverse conditions -- such as variable currents and high seas -- are an effective way to manage the rigors of staged decompression diving. Certainly worth learning how to use and certainly worth carrying in your wreck diving tool kit."

Of course it was also said that Jon Lines are not a panacea, but then, what is?

Doppler

[ericfine50]

Paul.

I like using a Jon line, I know a few people that use there spool as a "jon line". What ever works for you and you are comfortable using, use. Dog leash, Jon Line, spool what ever. I think the important part if being able to keep your stops (bouyancy control). Something I am always working on,
Eric

[metridium]

IIRC, I read a Tech 1 report that mentioned Andrew teaching how to use a spool as a jon line.

[metridium]

My bad. It was Fraser Purdon, GUE Tech 1 instructor, not AndrewG.

Here (http://www.scubadiving.com/members/tripreports.php?s=658)

[O-ring]

They were also used when GUE dove the Brittanic, so they obviously have their place in certain applications.

[Walter]

Who believes they are dangerous?

[O-ring]

Walter once bubbled...
Who believes they are dangerous?

[Epinephelus]

I've always heard the term "Jon" line used to mean a short line, what I grew up calling a "sissy" line, that can be used for all sorts of things - lift line, buddy line, fish stringer, stand-off (from the anchor line) line, reef hook line, etc.
Is that the "Jon" line y'all are talkin' about? Some of the posts seem to be talking about something else, like a down line or a Jersey line...
What, precisely, is the Jon line in question?
E. itajara

[ericfine50]

Yes. allows you to stand off teh anchor line and deco. Helps with the surge, large group dives, etc...

Eric

[Walter]

A jon line is attached (usually with a clip) to the anchor/mooring line. The diver then retreats to the end of the line. It is very useful in a combination of current and seas. Floating free works well to keep you at the same depth in seas, but when current is also present, the jon line keeps you from drifting away. On crowded ascents they are handy to get you out of the crowd, so in that situation I use one even in the absence of seas. I normally use a buddy line as a jon line because I am able to adapt it for so many situations/uses.

[O-ring]

...in the sense that they can be used at gas switches since you are about to spike your ppo2 from whatever you were diving for the working portion of your dive up to 1.6. If you were to tox at a gas switch, it seems more likely that you will be rescueable if you are attached to the line where your buddy can get to you instead of flying in the current and possibly sinking.

The scenario here was one where we were NOT live boating, so drift deco was an undesireable last resort. This was an ascending the anchor line scenario. Obviously, a jon line has no place doing a drift deco...what would you attach it to? :D

We never got anywhere on this though I don't think...good discussion topic though..

[Braunbehrens]

In my opinion jon lines are a compromise that carries too much risk. Diving is all about accepting a certian level or risk. There are simply too many thing that can go wrong with a jon line. Drifting the deco is a much safer alternative.

Before I get jumped by people who are going to tell me that there are places where you can't drift....well, there are places where you can't dive. If you want to make this compromise in safety because you feel the goal is worthwhile, then that is your choice.

However, saying that it is safer to use a Jon line when doing a gas switch is in my opinion a mistake.

If you do the gas switch properly, and this means that you are in close proximity to your buddy and you are observing each other, the Jon line will only add more problems.

This scenario also assumes that you not only use a Jon line, but that you are clipped into the jon line. Clipping to the jon line is adding even more danger to an already dangerous situation.

I hope I'm not being rude in any way here, and I'd be glad to discuss any of this if we can keep it polite.

[JeffG]

Braunbehrens once bubbled...
In my opinion jon lines are a compromise that carries too much risk. Diving is all about accepting a certian level or risk. There are simply too many thing that can go wrong with a jon line. Drifting the deco is a much safer alternative.

Before I get jumped by people who are going to tell me that there are places where you can't drift....well, there are places where you can't dive. If you want to make this compromise in safety because you feel the goal is worthwhile, then that is your choice.

However, saying that it is safer to use a Jon line when doing a gas switch is in my opinion a mistake.

If you do the gas switch properly, and this means that you are in close proximity to your buddy and you are observing each other, the Jon line will only add more problems.

This scenario also assumes that you not only use a Jon line, but that you are clipped into the jon line. Clipping to the jon line is adding even more danger to an already dangerous situation.

I hope I'm not being rude in any way here, and I'd be glad to discuss any of this if we can keep it polite.

What is the compromise that you are speaking of?
What are the "more problems" that the Jon line creates?
What the additional danger that is being added to the situatation?


Where's the Beef?

[JeffG]

roturner once bubbled...


It must be dialect. What's a " Jon line"? Is that what I might call a "buddy line", a short rope that both divers hold onto during the dive?

R..

Walters Post

A jon line is attached (usually with a clip) to the anchor/mooring line. The diver then retreats to the end of the line. It is very useful in a combination of current and seas. Floating free works well to keep you at the same depth in seas, but when current is also present, the jon line keeps you from drifting away. On crowded ascents they are handy to get you out of the crowd, so in that situation I use one even in the absence of seas. I normally use a buddy line as a jon line because I am able to adapt it for so many situations/uses.

[O-ring]

Before I get jumped by people who are going to tell me that there are places where you can't drift....well, there are places where you can't dive. If you want to make this compromise in safety because you feel the goal is worthwhile, then that is your choice.
There are places you can't drift and in those places, should I decide the goal is worthwhile and I choose to dive, I may choose to use a jonline.

[Doppler]

Would it be possible to actually get some facts here...


Braunbehrens once bubbled...
In my opinion jon lines are a compromise that carries too much risk. Diving is all about accepting a certian level or risk. There are simply too many thing that can go wrong with a jon line. Drifting the deco is a much safer alternative.

It's not clear what safety rules a Jon Line compromises, and why drifting is "a much safer alternative." Both have suitable applications.

Now, if I read this correctly:


Braunbehrens once bubbled...
Before I get jumped by people who are going to tell me that there are places where you can't drift....well, there are places where you can't dive. If you want to make this compromise in safety because you feel the goal is worthwhile, then that is your choice.

You are saying that if there is a current, and drifting or live boating is not possible, you see the risk as too great and therefore will not dive. Is that correct?

If that's your opinion, I support your right to hold it... after all: Anyone can call any dive..... etc. etc. Just as long as you're not going to be judgemental about those who hold a different opinion.

It just seems that these discussions quickly degenerate into a pissing contest where one side is black and the other is white... when mostly, there is a huge gray area....

Now, there are some side issues here about gas switches and that's how these discussions get hijacked. Let's try to stay focused on the central issue...

Using a Jon Line is an acquired skill... just like anything else. Jon Lines are not advised on every dive, and should only be carried when needed (Hogathian rules) but I fail to see how a simple piece of climbing webbing with a couple of loops in it, is -- in and of itself -- dangerous.


Doppler

[DiveTub]

I love my jon line and use it on every Deco Dive, why would anyone want to hang onto a bouncing mooring or anchor line with 10 other people when you can tie off, hang back and have a comfy deco.

Mine is 3m long and made from Shock cord, it is great as if there is any bounce it stretches and takes out the pulling nicley.

[Walter]

"only be carried when needed (Hogathian rules)"

I disagree. I carry my multipurpose buddy line on every dive. In the event I need to rescue a panicked or exhausted diver on the surface, I use it to tow the diver. A quick loop around around the tank valve and I'm in position to make a safe and relatively easy tow.

It's part of my standard safety equipment.

[techdiverKP]

It's been said already, but having a jon line to get away from the crowd at that 10-15-20ft stop is a stress reliever in a major way. It also keeps you from getting lazy, letting the down-line/anchor line affect your stop depth. Pinpoint buoyancy and a good jon line can make for a relaxed and safe deco in some conditions.

It CAN even be used on drift decos if you're doing a group drift on a down-line. In high-current, open ocean dives, it's a lot safer and more relaxed doing your deco that way, with a live boat on the surface tracking the surface float that your down-line is attached to. Much easier to splash support divers on also if your entire group is decoing on one free floating down line.

[Rick Murchison]

My sissy line is an essential piece of my dive equipment. I can use it like a "jon" line, or to tie a lift bag onto a treasure, or to string a fish, or to keep a buddy close in poor viz, or to hook into a reef, or mark a spot, or to give a stressed diver something to hang onto while being towed, or to clip equipment off to a down line, or to solve a problem I haven't even run into yet.
Mine is only about 4.5 feet long, with a bolt snap on one end and a suicide snap on the other. It's made of braided poly with the loops fashioned by slipping the end of the line back into the center of the line, so like one of those Chinese finger grabber toys the loops are secure when tugged on, but can be released in half a heartbeat with a simple tug at the right spot in the right direction. There's one in the pocket of every one of my BC's and three or four extras in my save-a-dive kit. If I were the "dive king" every diver would carry a sissy line on every dive. (I'm not the dive king and y'all do whatever you want).
I've been using a sissy line for over 30 years diving, and have never, ever, seen, experienced or heard of anyone having any safety issue (other than using one to save their bacon) with one.
Rick

[Doppler]

Rick Murchison once bubbled...
My sissy line is an essential piece of my dive equipment.

SNIPPED

Mine is only about 4.5 feet long, with a bolt snap on one end and a suicide snap on the other.

Great post Rick... dive King in waiting... just wish you'd loose the suicide clip! They're aptly named you know!!! ;)


Doppler

[Rick Murchison]

Doppler once bubbled...
just wish you'd loose the suicide clip! They're aptly named you know!!! ;)
Yes, they are, and one should give much thought to when and where one is appropriate - and whether something else might do just as well. In this particular case, when the clip only comes out of a pocket to be used for a specific purpose, and the rig allows the instant easy ditch of the clip if required, and I want to be able to grab something with the motion and the ease that only a suicice clip provides, I decided to use one.
Rick :)

[jengineer]

sure is getting a lot of air time. Bet he wishes he could get a nickle for time this subject comes up. I used to use one many years ago but a lift bag and a spool do nicely for drifting deco and If i must be tied to an anchor in howling current the spool does just fine. My J-lines are now relegated to walking the dog (and that is not a yo-yo term)

je

[ericfine50]

While we are on the Subject. Can someone explain how to use the reel. Heard about it, never tried it.

Thanks
Eric

[Braunbehrens]

ericfine50 once bubbled...
While we are on the Subject. Can someone explain how to use the reel. Heard about it, never tried it.

Thanks
Eric

Basically you use a reel when you want to be able to get back to a certain point. This can be very useful in wrecks, caves, bad visibility, or just making sure you get back to the boat.

Basically, you tie the end of the line onto a rock. You then make another tie a few feet away. Then you "lay line". You reel out, and every once in a while you loop the line around a rock (or whatever) to keep it neat. Once you decide to turn around, you reel back in, undoing the wraps as you encounter them.

There is a bit more to it than that, but that's the basic idea. Let me know if you have any specific questions.

It's good to have someone show you how to use one, because having a lot of loose line underwater can be quite dangerous.

Also, some reels are better than others. Some reels tend to foul the line or come apart...not good.

You can also lay line with a reel and then leave it in place for future dives.

[metridium]

Ummm....

I think he meant how do you use a reel/spool as a jon line.

If not, I do.

[O-ring]

metridium once bubbled...
Ummm....

I think he meant how do you use a reel/spool as a jon line.

If not, I do.
That's what he meant...how to use one as a jonline. He's full cave, so I would imagine he has a vague idea of how to use a reel/spool...

[metridium]

O-ring wrote...

He's full cave, so I would imagine he has a vague idea of how to use a reel/spool... Thought so...

:D

[O-ring]

metridium once bubbled...
Thought so...

:D


It seems we lost the original thrust of the conversation - are jonlines good or bad, useful or non-useful, dangerous or safe, etc.

I think a few good points in favor of jonlines have been made, but I haven't seen a whole lot of negative points about jonlines yet. I think that in certain places, such as Florida, you could argue that jonlines are an unnecessary complication because they are totally not needed. I think that argument has a lot of merit, in the Hogarthian sense, since the boats tend to not shackle the wrecks and allow the divers to drift deco. In the Mid-Atlantic and Northeast (I can't speak for the PNW and other areas), the boats tie into the wrecks, may or may not have a chase boat, and tend to venture into areas with low vis, potentially fast currents, and cold water (I don't mean 60-70 Florida cold, I mean NE 30-50 cold). In this scenario, I am having trouble seeing the harm in a jonline unless it is being used as a crutch for bad buoyancy/fundamental dive skills.

[Braunbehrens]

I've been asked to make a post explaining why jon lines are bad, but I'm hesitant to do so because of the earlier unpleasantness.

Still, to answer a few specific point O-ring made in his last post, or maybe more accurately, expand on them.

Cold water is one more reason not to use a jon line. It is colder to flap in the breeze than to drift in the current.

Bad visibility is another reason not to use a jon line. As soon as one person let's go he's out of sight and unlikely to find his way back.

As for jon lines being used as a crutch instead of poor buoyancy control or worse having a balanced rig, yes, that is a major reason, but not the half of it. What's far worse is that even with good buoyancy skills the diver is usually not neutral at the jon line and should he get blown off will be up the creek as well.

The argument that "it's done a certain way around here" is TO ME not valid. I will do the dive if I deem it safe enough. If it isn't, I simply won't dive. I don't really care that the locals do something I feel is unsafe.

I think jon lines add a lot of risk. IMO an unacceptable amount. However, everyone is free to take on as much risk as they want, of course.

There are really 3 scenarios. One a jon line is not needed at all, because there is no current. Two, there is current but the dive can be done doing drift deco. Three, drift deco is not possible.

I am saying that in 1 and 2 drift deco is safer, and 3 means that I'll be seeing the sights above water.

I'll probably get crucified again for this....go ahead.

[O-ring]

Braunbehrens once bubbled...
I've been asked to make a post explaining why jon lines are bad, but I'm hesitant to do so because of the earlier unpleasantness.

Still, to answer a few specific point O-ring made in his last post, or maybe more accurately, expand on them.

Cold water is one more reason not to use a jon line. It is colder to flap in the breeze than to drift in the current.

Bad visibility is another reason not to use a jon line. As soon as one person let's go he's out of sight and unlikely to find his way back.

As for jon lines being used as a crutch instead of poor buoyancy control or worse having a balanced rig, yes, that is a major reason, but not the half of it. What's far worse is that even with good buoyancy skills the diver is usually not neutral at the jon line and should he get blown off will be up the creek as well.

The argument that "it's done a certain way around here" is TO ME not valid. I will do the dive if I deem it safe enough. If it isn't, I simply won't dive. I don't really care that the locals do something I feel is unsafe.

I think jon lines add a lot of risk. IMO an unacceptable amount. However, everyone is free to take on as much risk as they want, of course.

There are really 3 scenarios. One a jon line is not needed at all, because there is no current. Two, there is current but the dive can be done doing drift deco. Three, drift deco is not possible.

I am saying that in 1 and 2 drift deco is safer, and 3 means that I'll be seeing the sights above water.

I'll probably get crucified again for this....go ahead.
I just think that "they do it around here" is more valid for certain people. Where do you do most of your diving? The only reason I ask is that if you were to get on a boat up here and say, "Hey, Cap'n, I am going to intentionally NOT come up the anchor line, but am instead going to make a free ascent to 70' and shoot a bag. Then, I want you to track me and send a chase boat so that I can be picked up after my deco. Ok?", you would not be diving.

I understand the arguments about chartering our own boats and doing it our way, but it is VERY hard to pull that off due to scheduling (instead of 1-2 members of the team needing to be available on a given weekend to dive with me, now I have to find enough to fill the boat) and weather (little teeny boats can't go out up here very often...the seas can get pretty snotty) coupled with distance (all our decent wrecks are at least 2 hours offshore - hard in a little boat). Believe me, we have talked about it...to the point that we actually sat down and talked about everyone chipping in and buying our own Zodiac...

[GearHead]

Braunbehrens once bubbled...
There are really 3 scenarios. One a jon line is not needed at all, because there is no current. Two, there is current but the dive can be done doing drift deco. Three, drift deco is not possible.

I am saying that in 1 and 2 drift deco is safer, and 3 means that I'll be seeing the sights above water.

I'll probably get crucified again for this....go ahead.

Do you really see those as the only three scenarios out there?

Let me throw a hypothetical situation your way:
(I hope you don't consider this crucifixion)
You're planning a trip to dive a wreck, a spectacular wreck, and the boat ride out there is long and hard. When you get to the site, the wreck is hooked and a strong, constant current is observed. There is no chase boat, and drift deco is not an option.

Are you saying that you would not take a trip like this because of the possibility of strong current?

Or would you take the trip with the hope that the current won't be strong and you can do a normal hang, but because of the current, you sit on your hands and count seagulls?

Or, would you use a Jon-line?

I'm curious to hear what you think.

[O-ring]

Is the GUE Brittanic expedition. They were in ripping currents in shipping lanes in the Kea Channel. They used jon lines to conduct the dive due to the conditions and the danger of being blown off and drifting in shipping lanes.

They decided the dive was worth the risk...likewise, I decide some dives are worth the risk too.

[Pez de Diablo]

Braunbehrens once bubbled...
<snip>
Cold water is one more reason not to use a jon line. It is colder to flap in the breeze than to drift in the current.<snip>

I am not trying to be unpleasant, I have taken my civil *discussion* to PM's so as not to look like I am crucifying you for you opinion.

I bring this up in the thread as it could sway my and others decision to use a Jon line.

In my opinion this is not true, do you have any backup data to substantiate this claim that it is warmer to drift in a current than remain on an up line?

[Braunbehrens]

pez, when you are drifting less water passes over your suit and you cool off less. When you are hanging in a current more water passes over the suit.

Same as windchill.

The other problem is that if you have a suit problem the current will probably fill your suit with water and continue cooling you much more than if you were drifting.

O-ring. Yes, I agree with you. If the dive is worth the risk to you, then you do it.

As for me, Gearhead, I would sit on the boat. It's not worth it to me. If the current is ripping and you get blown off....it's just too dangerous IMO.

If I really wanted to do it I might take a waterproof GPS, a waterproof VHS and an EPIRB, stuff them in a watertight tube and carry them as a stage....but more than likely I just wouldn't plan the trip in the first place.

I completely understand the problems of boat operators wanting to do things their way. It is certainly a difficult situation which I am glad not to have to deal with.

[O-ring]

...and take the jonline out of the picture. Let's say you weren't sure if there was going to be current, but you were pretty sure there wasn't much. Would you go in with the restriction that you are supposed to come up the anchor line instead of drift decoing? Maybe you would just hang onto the bar.

What about in a recreational setting...like in North Carolina. You are doing a 65' wreck, no deco, and you are supposed to come up and down the line - doing your safety stop on the line.

Still too risky? Are you objecting to the jonline specifically or just the "no drift deco" thing?

[Pez de Diablo]

Braunbehrens once bubbled...
pez, when you are drifting less water passes over your suit and you cool off less. When you are hanging in a current more water passes over the suit.

Same as windchill.
<snip>

OMG I don't buy it. Not at all. The water rushing over my suit would cool me off more than drifting in the same water? You substantiate this claim by saying it the same as wind chill. Great response.

We'll agree to disagree.


Braunbehrens once bubbled...
<snip>
If I really wanted to do it I might take a waterproof GPS, a waterproof VHS and an EPIRB, stuff them in a watertight tube and carry them as a stage....but more than likely I just wouldn't plan the trip in the first place.<snip>
LOL

Where is that jug of coolaid?

While you are waiting on the boat for the rest of us, I'd like you to keep the coffee hot and fresh and if you don't mind, whip up some sandwiches and soup for us. We'll tell you all about our great dive while we eat.

[bridgediver]

Pez de Diablo once bubbled...


OMG I don't buy it. Not at all. The water rushing over my suit would cool me off more than drifting in the same water?

Actually pez, the water rushing over you will produce friction between the water molecules and the suit thereby creating heat so you will actually get warmer from using a jonline.

;)

seriously though... windchill does NOT work the way described by Braun. The air and undergarments in the suit are designed to insulate the diver and keep in warmth. The dry suit can be thought of as a wind breaker (or water barrier). As long as the wind (or water) is kept away from the insulation it doesn't matter how much wind (or water) passes over said diver.
The only factor being relative temperature; for that more or less insulation may be required. The wind (or current) doesn't make the temperature colder.

Now... if you were in a strong current on a jonline naked....
bbbrrrrrrrrrrrrrr!!!


my 2 cents (canadian$)

[filtered]

Can someone explain how to use the spool as a jon line? :)

[Braunbehrens]

Regarding current and cold. Boil 3 eggs. Put them in a bowl under the cold water tap. Fill the bowl with cold water. Wait 1 minute and take the eggs out.

Now do the same, but let the water run the whole time.

Which eggs do you think will be warmer?

Cold was brought up as a reason FOR using a jon line. I'm just saying that if anything, you'll be colder hanging on the line than drifting in the same water.

Now hopefully you are well insulated and it's not that big a deal, but you certainly will be cooler hanging than drifting. How much cooler, I don't know, but I'd be happy to study the matter if you'd all be so kind as to pay for my research ;-)

Bridge, you really think that wearing a windbreaker you will not feel windchill at all? Most of the heat is lost through the head, which usually is in a wet hood. Current increases water circulation in the hood and over the face.

I can't believe you guys would argue something that is a) so obvious and b) such a minor point in the whole jon line thing.

If you really wanted to argue it just say that whatever the conditions are on the jon line you'll be prepared for it with proper exposure protection. Period end of story. Just don't tell me that cold is a reason why it's better to hang on to a jon line.

O-ring, your question is pretty complicated. How many chase boats, how many teams, how far from shore etc.?

I do most of my diving off a small anchored boat with no one on board, and we come up the anchor. However, I don't dive far enough from shore so that swimming back would be a real problem.

Whenever possible we live boat.

If I feel that the current will be a problem then I won't do a dive requiring real deco.

(as opposed to fake deco, which everyone knows means doing just a few 1 mn stops on the way up ;-)

[Scubaroo]

Braunbehrens once bubbled...
If I really wanted to do it I might take a waterproof GPS, a waterproof VHS and an EPIRB, stuff them in a watertight tube and carry them as a stage....Hey O-ring! Still got that AUL canister handy?

You could probably stuff a bottle of Aquafina and some Clif bars in there as well :)

[Charlie99]

Braunbehrens once bubbled...
Regarding current and cold. Boil 3 eggs. Put them in a bowl under the cold water tap. Fill the bowl with cold water. Wait 1 minute and take the eggs out.

Now do the same, but let the water run the whole time.

Which eggs do you think will be warmer?

Now do the experiment that more closely matches the drysuit dive:
boil 3 eggs, put them in a THERMOS BOTTLE, then run your experiment.

The outside of the drysuit is at the water temperature whether or not there is current.

Charlie

[MikeFerrara]

Paul is right about heat transfer. Divers loose most heat through convection and conduction. Water can't pass through a dry suit but heat can. Every one knows that scootering is colder than swimming. If you don't believe me as the OCDA guys. They're doing long scooter dives in cold caves.

Next subject...

I haven't done a lot of wreck diving in strong current. Most of our Great Lakes dives have little or no current though that isn't true everywhere in the Lakes.

I can see the advantage to drifting deco. Simple enough you're not being battered by the current. My question is if you are going to drift is a bag the best way to do it or would you be better off with a drifting decompression station that you cut loose when you start deco. Isn't there a concern of the boat loosing track of a little bag in rough seas especially if there are multiple teams?

[O-ring]

Scubaroo once bubbled...
Hey O-ring! Still got that AUL canister handy?

You could probably stuff a bottle of Aquafina and some Clif bars in there as well :)
Yeah, that would make a handy waterproof, emergency kit... Can't do that right now...it is serving as primary light since my Halcyon was defective..

[Pez de Diablo]

Mike,

I agree that you lose heat through convection and conduction, but I would think that the difference in the situation described would be negligible and would not weigh heavy when planning the dive.

Maybe the guys doing the long scootering are colder because they are not as active:)

[runvus4]

filtered once bubbled...
Can someone explain how to use the spool as a jon line? :)


Basicly you:
1) Achieve neutral bouyency
2) Loop the spool or reel around the ascent line
2a) Tie off the spool or reel around the ascent line
3) Roll out to the distance you want to stand off the line
4) Clip the double ender on the spool so that the line won't unspooll any further or screw down the reel so it won't unreel anymore
5) Hold onto the spool/reel
5a) Use the other end of the double ender and clip it off.

The a) options are IMHO less desirable as they make a connection that is harder to release, but can have their uses, and it's always nice to have both hands free.

IMHO, being clipped off and having the water pass over you WILL be colder than drifting. The difference however should be unnoticable/negligable in term of comfort or hypothermia risk if you were using proper exposure protection.

Braunbehrens is expressing his opinion, not a statement of fact. In some ways I agree with him, but in practice that would make many wreck diving sites undivable. I personally think that the increased risk of a "Jon line" used by capable divers when is the line is not hard attached is negligable compared to other common "local practice" dive activities, such as cave diving, ice diving, wreck penetration, deco diving, etc. As he said, it's all about personal tolerance and assumption of risk for the diving youare doing, and for me, that means that Jon lines are acceptable when properly used.

[Braunbehrens]

Charlie99 once bubbled...
Now do the experiment that more closely matches the drysuit dive:
boil 3 eggs, put them in a THERMOS BOTTLE

Charlie, I want the name of your suit! I freeze my @$$ off even with thinsulate. Thermos? I wish.

;-)

[Braunbehrens]

Ok, so you're doing this wreck dive with deco etc., and you're hanging on the anchor line with your jon line. Let's say that there are 4 teams at different depths.

What do you do if 2 teams don't make it or get blown off?

What do you do if the boat has to leave, and puts a float on the anchor? Typically this will lower the anchor line quite a bit, possibly causing people at the 70 and 20 ft stops to tox?

It just seems like a lot of stuff could go wrong!

BTW, I really think the cold issue is totally minor. I'd much rather explore the risks of jon lines an what you guys do to minimize them.

[bridgediver]

Braunbehrens once bubbled...
Regarding current and cold. Boil 3 eggs. Put them in a bowl under the cold water tap. Fill the bowl with cold water. Wait 1 minute and take the eggs out.

Now do the same, but let the water run the whole time.

Which eggs do you think will be warmer?



The eggs that you ran the water over will be colder because they aren't insulated. Not them same situation as a diver in a suit.


[i]Braunbehrens once bubbled...
Bridge, you really think that wearing a windbreaker you will not feel windchill at all? Most of the heat is lost through the head, which usually is in a wet hood. Current increases water circulation in the hood and over the face.

[/B]

No, I would not say that. But if the person had a complete wind barrier, e.g. hood, pants, mitts, mask etc. then I would. You are correct that most of a person's heat is lost through the head. Windchill causes problems to exposed skin or areas of clothing that wind is able to penetrate. So, in the case of a diver with his mouth exposed I suppose that it could make you colder but insignificantly so from a physiological stand point. I would consider a wet hood to still be a good insulator though because water doesn't circulate inside of it - so you effectively still have a barrier and an insulator (admitably not as good as a dry suit).



Braunbehrens once bubbled...
I can't believe you guys would argue something that is a) so obvious and b) such a minor point in the whole jon line thing.

Just don't tell me that cold is a reason why it's better to hang on to a jon line.

[/B]

I agree that it is a minor point, just joining in the discussion (I think that you brought it up though?). I confess that I don't know squat about jonlines but I do know LOTS about windchill having spent a fair amount of time in the northern latitudes so I'm only speaking about what I know... didn't mean to detract from the intent of the thread. I think cold is cold. Whether you're drifting or hanging it won't make any difference.

friends?
:)

[Braunbehrens]

bridgediver once bubbled...

friends?
:)

I didn't mean come off as unfriendly, sorry if I did. I think the cold issue is not that relevant to begin with...but since we are on the subject.
Heat loss through the head is amazing. I was sitting with my wife and she complained that her feet were cold. I suggested she put her hood on. She looked at me with that "what are you, an idiot?" look ;-)

I finally got her to put on the hood, and a few minutes later her feet were fine.

A proper hood is an oft overlooked part of diving equipment. I got a 10 mm hood, and it actually made a difference in how warm I felt during deco.

[GearHead]

OK, I assume we're still going with the hypothetical situation of a wreck charter anchored to the wreck, no chase boat, and high current.


Braunbehrens once bubbled...
Ok, so you're doing this wreck dive with deco etc., and you're hanging on the anchor line with your jon line. Let's say that there are 4 teams at different depths.

What do you do if 2 teams don't make it or get blown off?


If that highly improbably scenario occurs, then the teams that get blown off are going to have to do drift deco, and hopefully spotters on the boat will see their SMBs and keep track of them until pickup.


Braunbehrens once bubbled...
What do you do if the boat has to leave, and puts a float on the anchor? Typically this will lower the anchor line quite a bit, possibly causing people at the 70 and 20 ft stops to tox?


Why would a chartered boat have to leave divers in the water? The only two scenarios I can think of are:

1. A diver or dive team blows their deco and need to get to a chamber.
If I'm the charter captain and I still have teams in the water, depending on my location, I'll probably stay put and call the Coast Guard for an airlift. Floating the anchor line on a buoy and ditching the dive site doesn't make any sense to me at all . . . except in scenario #2

2. Godzilla surfaces 200 yards away and starts heading for the boat.
Cut the lines gentleman, we're outta here!

[Rick Murchison]

Braunbehrens once bubbled...
pez, when you are drifting less water passes over your suit and you cool off less. When you are hanging in a current more water passes over the suit.

Same as windchill.
Sorry Braun,
It just ain't so.
There's no evaporative cooling underwater, and there's no conductive warming of the water around the dry suit.
Nope, current makes no difference.
Now, if you're in a wetsuit, or in bare skin, that's a different matter. But a dry suit... nope.
Rick

[LUBOLD8431]

I use a jon line and I'm not ashamed of it... I just dont get why you wouldnt when we dive up here in NE with currents, and no liveboating. You really NEED to go back up the upline.

[Rick Murchison]

MikeFerrara once bubbled...
Paul is right about heat transfer. Divers loose most heat through convection and conduction. Water can't pass through a dry suit but heat can. Every one knows that scootering is colder than swimming. If you don't believe me as the OCDA guys. They're doing long scooter dives in cold caves.
I think you're overstating the change in conductive heat transfer through a dry suit. Scootering is probably colder because (1) there's more conductive heat loss in the face and hands, and (2) you're not working as hard and therefore generating less body heat.
The inner surface of a shell is going to essentially be the same as the outside water temp regardless of water movement across it, and as the air inside is trapped, there's no reason that the conductive transfer of heat across the shell should be any greater in moving than still water.
I haven't done any really long scooter trips, but my limited experience tells me that I get colder scootering than swimming, but colder still during a deco hang with no activity - even if there's no current.
Rick

[Braunbehrens]

LUBOLD8431 once bubbled...
I use a jon line and I'm not ashamed of it... I just dont get why you wouldnt when we dive up here in NE with currents, and no liveboating. You really NEED to go back up the upline.

Well, what you really want is a live boat and a chase boat for each team...but I understand why you guys use jon lines.

I was just looking through the quest archives because I remember discussing jon lines with Trey. At the time I was arguing for them...well not really arguing for them, just presenting them as an inevitable part of diving in some circumstances.

Funny how things change...

I still think they are dangerous. But I understand why they are used...basically, it's cheaper than to have a live boat and a bunch of chase boats.

[ericfine50]

Paul,

I don't think Jon Lines are the "cheaper" alterative to live boating. Another thing that has not come up, is a lot of divers go out on charters that are not all made up of the same team. So, you could have 6, 8,10 teams of divers on different dive plans and some boats go to two different wreck sites. It is another optiuon on how to deco and needs to be considered. And thanks f or the explaination of how to use the spool as a Jon Line.

Eric

[Rick Murchison]

On my list of dangerous things you can do while diving, drifting out of sight of the boat is way, way above anything you can do to yourself with a jon line.
Rick

[O-ring]

ericfine50 once bubbled...
Paul,

I don't think Jon Lines are the "cheaper" alterative to live boating. Another thing that has not come up, is a lot of divers go out on charters that are not all made up of the same team. So, you could have 6, 8,10 teams of divers on different dive plans and some boats go to two different wreck sites. It is another optiuon on how to deco and needs to be considered. And thanks f or the explaination of how to use the spool as a Jon Line.

Eric
We get that a lot down here too...especially on the marginally technical stuff - i.e. wrecks in the 110-130 range. There may be 3 buddy teams of divers planning to do deco dives on the wreck and then another 4-5 teams just doing a no-deco recreational dive on the wreck. They all come up at different times and are not all trained to do a drifting deco/drifting safety stop. These mixed boats would make it really hard to pull the anchor and go chase divers that decided to come up off the line.

[ericfine50]

exactly.
Eric

[patmandu]

I agree with what everyone has said about the live boating vs the tied-in boat that we seem to have up here in the northeast.

Since my 'trip report' was used an example, I thought I'd clarify a little on what we learned and how we implemented it.

yes, Fraser showed us how to use a spool as a makeshift jon-line. No, we never clipped ourselves off to the spool to go 'hands free'. No, we never used this solution in a 'ripping current'; we drifted using a live boat when the condition warranted it.

The reason we used the Joh-line then and I have used the same procedure in the caymans, and up here in the NE is when there is an 'annoying' little current blowing and you have a longer stop (i.e. 20ft). Constant lazy finning or occasional finning to keep around the anchor line while your supposed to be 'relaxing' and decoing is a PITA. I'm not talking a ripping current and holding on for dear life.....come on, would you trust the line on spool for that?

Instead we tie off and hold onto the spool so that we don't have to kick all the time to keep in sight of the line and our buddies. I'm not seeing any danger in this at all. We aren't hanging off the line, so that 'ups' and 'downs' in the mooring line are going to jerk us to tox depths or anything of sort. And, we aren't hanging out like a blowing flag. Simply it's an aid in slight current where you don't want to be 'excercising' during deco.

Make sense?

--Pat

[daylight]

Pat,
It's good to see a post that demonstrates reality and common sense.
thanks,
Larry

[ericfine50]

Pat.
Thanks for the info.
Eric

[Braunbehrens]

patmandu once bubbled...
Instead we tie off and hold onto the spool so that we don't have to kick all the time to keep in sight of the line and our buddies. I'm not seeing any danger in this at all. We aren't hanging off the line, so that 'ups' and 'downs' in the mooring line are going to jerk us to tox depths or anything of sort. And, we aren't hanging out like a blowing flag. Simply it's an aid in slight current where you don't want to be 'excercising' during deco.
--Pat

Sounds like a reasonable thing to do, so long as the current is light enough that if someone does let go they can get back easily.

[patmandu]

I've always thought it was a pretty reasonable thing to do, and was convienent.

To give a good example, I was doing a gas dive in the Caymans last year. Stops from 70 to 20 we experienced a slight current as we gradually made our back to the boat (which was moored for the recreational divers on the boat). With a 16 minute stop or 20' (or something like, I don't have wetnotes at the office) the slight current was sort of annoying. I'd stop kicking and notice myself 20ft or so from the downline, I'd then kick back to the line, and relax....then I'd be 20ft from the line again. UGH. I look over to the other down line (they hang two lines off the swim platform) and there's Fraser hanging onto his spool with two fingers and just enjoying his deco. Of course, I followed suit and enjoyed just watching the fish swim by and checking on my buddy as the time ticked off.

There is no way I'd tie off a spool in a ripping current. I just wouldn't trust the line to keep 'safe' and if the current were that bad, I'd never get back to the anchor line if the line snapped. No what I mean.

I think this is the case where people read something, and don't 'get' what is being said.

Just my .02