At what point do you run a line?

[rainman_02]

Ok, so this question springs from several discussions on "light penetration" or "swimthroughs" or whatever you want to call them.

Here are the extremes:

1) Open on three sides with an overhang that is big enough that you can't immediately go to the surface.

2) "Progressive penetration of wrecks/caves without line because you're memorizing your way in/out.

Now, #2 is decidedly not DIR. Is #1? Where does it switch from "ok to go under without a line" to "a line is mandatory?"


Let's hammer out some thinking...

 

[Kevrumbo]

Depth, Direction, Distance, Duration and Deco?
Mandatory or optional to return to the entry point?
Possible compromise of visibility (i.g. silt-out)?
Day or Night Dive?

 

[rainman_02]

Addendum: At what point do you seek out overhead training instead of it being "just a swimthrough?"

 

[Kevrumbo]

Read this thread about <a diver> habitually treating a Wreck at 120'/36m as a single tank swim-thru. . .

 

[rainman_02]

Right, so that falls at the #2 extreme. Extremes are not the point. Let's get into the grey area in the middle.

And she is more than welcome to do whatever she wants on a dive. I request you edit your post so it doesn't look like you're attacking her, etc. The point is the way "we" as DIR divers do it, not the way "they" as non-DIR divers do it.

 

[Kevrumbo]

Then get more training to give yourself a wider knowledge base in order to make a better informed decision about "the grey area in the middle" problem that you seek to resolve.:ne_nau:

 

[Sloth]

I'm new to this DIR thing but I was lead to believe that part of it is becoming a thinking diver. It seems like Kev was getting to that in his first reply. the variables have to be assessed before the dive and used to formulate the dive plan.

Should we go into an over head environment as a team without tie off?
Is the visibility known post dive is so what is it?
What is the condition of the site/wreck?
What is the potential for silt?
What is the teams training level?
What is the goal of the dive?

The default answer would probably be tie off in any overhead environment but in reality some common sense and risk assessment would be used. Hell, I swam under an arch in my fundies course. maybe I should have tied off first

I don't think you can set rules for all the shades of grey between examples 1 and 2.

 

[Cave Diver]

Depth, Direction, Distance, Duration and Deco?
Mandatory or optional to return to the entry point?
Possible compromise of visibility (i.g. silt-out)?
Day or Night Dive?

Addendum: At what point do you seek out overhead training instead of it being "just a swimthrough?"

I think Kev pretty much hit it. Its a decision you have to make based on the criteria he mentioned. My "general" criteria a for a "swim through" vs. "penetration" is more than one body length inside before I'm on my way back out again.

Obviously, a lot of variables play into that, such as being able to see the exit, ability to turn around, yada, yada, yada.

I think the short answer would be that if you have O/E training, you'll know what a "safe" vs "dangerous" penetration is as it pertains to you, your skill level and your equipment and if you don't have O/E training, you should treat any penetration as dangerous.

 

[FLDVR]

Rainman, your question is too ambiguous for one. Ask 20 divers "What is their perception of penetration" and you'll get as many answers.

Of course in Gue training the instructors usually will default to "Go to the horses mouth" for information. This question would be better served being asked on quest or a direct response from Gue then commented on here.

The overall answer probably lies in developing a " Thinking" attitude towards penetration and observing factors involved in a swim thru that may be beyond your limitations.

Some wrecks are prepared for divers, some are natural wrecks. Is one safer to swim thru as compared to another? These are points that can be addressed also.

Unless there is some guideline or rule that applies to all wrecks in all circumstances then the question will always remain, and the ultimate decision will be up to the divers recognizing and accepting a higher level of risk.

Henry

 

[RTodd]

Ok, so this question springs from several discussions on "light penetration" or "swimthroughs" or whatever you want to call them.

Here are the extremes:

1) Open on three sides with an overhang that is big enough that you can't immediately go to the surface.

2) "Progressive penetration of wrecks/caves without line because you're memorizing your way in/out.

Now, #2 is decidedly not DIR. Is #1? Where does it switch from "ok to go under without a line" to "a line is mandatory?"


Let's hammer out some thinking...

It is just too gray to answer. I admit to doing fairly long swimtrhoughs in the carribean without even considering a reel but I am with other experienced divers and it isn't like you can't exit most of these without a mask or light. Wrecks are much tougher to judge and it depends greatly on the individual's experience and the wreck. I don't run reels on the gutted, holes everywhere recreational wrecks and I will swim through them on a single tank. But, a deeper "non-cleaned" wreck in colder water - reel and doubles every time.

The best rule of thumb I ever received was from Trout when discussing not running a reel on scooter dives in the Ear at Ginnie. His rule, once you are comfortable exiting a particular cave with a busted ear drum, flooded drysuit and no mask or lights while sharing air, then you can skip a primary reel. For cave diving not running a primary is in almost all cases stupid. (Although in my view all lines should go to open water anyway.)