Safety Divers for Deep Dives - What Do They Do?

[JeffG]

I persl. find 80's a great bottle for staged deco dives......

Do you Need or Use 80's

That is two different concepts, but you knew that already.

I was not aware divers did not use them....and that the 40's was the only way to go.....dang must be a ton of deep divers in error. I even use 50's..... and steel on occasions when conditions warrant. I and a lot of divers must have missed the 40cf only rule for deco.

Where did I say it was the only way to go? I was just stating the configuration of our team.

Lots of people use lots of different stuff. Doesn't make it optimum though.

Again, you knew that already.

 

[texdiveguy]

Do you Need or Use 80's

That is two different concepts, but you knew that already.



Where did I say it was the only way to go? I was just stating the configuration of our team.

Lots of people use lots of different stuff. Doesn't make it optimum though.

Again, you knew that already.

OK.... I use 80's/50's as that is what I own persl.--my persl. choice,,,,,its also nice for multiple dive days,,,I find handling an 80s/50s as simple as a 40s....no need to carry multiple deco bottles to remote sites....many of the divers I dive with do the same. As to steel 72s they are great O2 or stage gas bottles.... I use them also as needed.

OK.... you are correct and 'I bad'....you did not say that it was the only way to go--40's....my reading error. 'Optimum' holds many different meaning to many folks....to me persl. it is optimal to use larger than 40s for deco.

"Lots of people use lots of different stuff."--- this is correct!

 

[JeffG]

OK.... I use 80's/50's as that is what I own persl.--my persl. choice,,,,,its also nice for multiple dive days

80's with 50% is a good tank for multiple dives. (I've never used 50's, so of those I cannot speak.)

'Optimum' holds many different meaning to many folks....to me persl. it is optimal to use larger than 40s for deco.

When your deco/stage tanks are all slung where they are needed, it doesn't matter all that much. I find cat 40's hang like bricks, but they are usable. (and I imagine steel deco bottles would be around the same)

It becomes more of an issue if you have to swap tanks in/out.

For my example of the Athel Viking dives.

Diver removes leash with 50% and 100% bottles. (and holds that in one hand)
(This is neg by a couple of pounds, but the leash makes it easy to hold)

Diver then removes 80 stage and clips this to the leash.
(The 80 is pos and the 40's are neg, but the leash "system" is close to neutral, so if you drop it...it doesn't drop like a rock, taking your deco bottles with it.)

Diver then takes the 40's and clips them to his harness. (This is the dangerous part. This is where it is nice to have a support diver...to get back on topic

Now, If he drops the leash now...no biggie, those tanks are done.

Now, change all those luxfer tanks and make them steel bottles. It changes the dynamics of the whole swap.

 

[fweber]

Whatever.

I guess it was lost on you.

 

[Rick Inman]

Yes, the 120' is easy pesy.

We had the 120' and 70' bottles clipped up front and the 20' bottle on the leash. We made the 70' switch, then moved the 20' bottle up front and the 120' back.

We dragged 80cf bottles of the 70' gas - not 'cause we needed the 80cf, but because it's what we had, all that extra gas is fun to have, and I wanted the practice with the bigger bottle.

I never moved the 70' 80cf back, but handed my used bottles off to the support divers during the final stop, just for something to do.

I guess it was lost on you.

On Jeff? Oh, I doubt that....

 

[fweber]

That right. Attack the person because you can't argue the facts.

Too rich.

Do you dive?

All right. I'll play along. Here's the scenario:

You would like to go do 2 dives of 20 minutes each on a 60 meter site. Because of space restrictions you are limited to 2 deco bottles each for the day. The site is far enough away, that you will not be returning for lunch. You have access to oxygen and the ability to continuous blend up to 40 percent, but no booster. You have 2 low pressure cylinders of O2(240@2200psi), 2 cylinders of helium(330cf@2400psi) and need to mix for a team of three. Your SAC for this is .85 bottom and .65 deco. Your team would like to see a 1.5 safety factor on your deco gas planning for the second dive.

I don't feel this is an unrealistic scenario for a traveling diver. In fact it's probably a fairly common one.

I know how I plan the dive. How are you going to do so? I think you may find that the most likely combinations require tanks and mixes other than AL40's and EAN50.

Let us know how it works out for you,

EDIT: I should add that if you're using vplanner use a conserv of +2 or the appropriate factor for decoplan etc.

 

[JeffG]

All right. I'll play along. Here's the scenario:

You would like to go do 2 dives of 20 minutes each on a 60 meter site. Because of space restrictions you are limited to 2 deco bottles each for the day. The site is far enough away, that you will not be returning for lunch. You have access to oxygen and the ability to continuous blend up to 40 percent, but no booster. You have 2 low pressure cylinders of O2(240@2200psi), 2 cylinders of helium(330cf@2400psi) and need to mix for a team of three. Your SAC for this is .85 bottom and .65 deco. Your team would like to see a 1.5 safety factor on your deco gas planning for the second dive.

I don't feel this is an unrealistic scenario for a traveling diver. In fact it's probably a fairly common one.

I know how I plan the dive. How are you going to do so? I think you may find that the most likely combinations require tanks and mixes other than AL40's and EAN50.

Let us know how it works out for you,

and what has this to do with safety divers?

or should I just whip out my **** and measure it right now?

 

[Hank49]

or should I just whip out my **** and measure it right now?

Uh oh Jeff.....see you in a couple weeks?

 

[fweber]

and what has this to do with safety divers?

or should I just whip out my **** and measure it right now?

Not meant as pissing contest at all. It has to do with this statement:

If you need an 80 deco bottle, you shouldn't be doing dives like that.

and I won't even mention the use of steel deco bottles.

and your assertion that all dives can be covered with AL40's of EAN50 and O2.

 

[JeffG]

and your assertion that all dives can be covered with AL40's of EAN50 and O2.

I made no such assertion.

But knock yourself out reading stuff into my posts that you want. Thats ok with me.


I gave an example of a dive that I believe should have safety divers.

The moment that gear needs to be swapped/moved around is a disaster waiting to happen.

Thats why I feel that safety divers deep is a waste of a scarce resource. What really is going to happen? Just like the 120 stop. Take reg out of mouth....put reg in mouth. Kinda hard to really mess that one up.