dive to 300 ft

[PfcAJ]

Or dedicated travel gas.

Def not. Deepest deco gas.

 

[rhlee]

For those that have done > 200' deep dives, aren't most of those done with a support team? That not only do you have all these stages of travel and deco gas, but a support diver who comes part way to check for problems?

Just something I've gathered from reading . . . .

I think the short answer is "maybe".
A dive in this range is a fairly serious dive, so there is unlikely to be one "right" answer. The "thinking diver" is going to evaluate the environment, team, and other parameters of the dive and make sound planning choices (based on training, experience, environment and conditions, etc.) that are going to be appropriate for the dive.

 

[lamont]

NOTE: PLEASE KEEP IN MIND THAT YOU ARE IN THE DIR FORUM

There are some fairly precise answers to this question which the OP seemed to be interested in. Either stick with DIR standardized gasses, etc -- or else I can bounce this question out of the DIR forum and into the broader tech diving forum...

 

[LiteHedded]

Or dedicated travel gas.

nope.

 

[Blackwood]

For those that have done > 200' deep dives, aren't most of those done with a support team?

It probably depends on conditions, but around here you aren't going to see people using support divers for recreational dives even to 300 feet.

 

[nadwidny]

Good day,

In the thread Accidents and Incidents > Cozumel Incident 9/4/11 it has been contended that some divers planned to dive to 300 ft on a single AL 80 or AL 100. Regardless of what happened in Cozumel and irrespective of whether or not these rumours are correct, I am curious how properly trained DIR divers would execute a dive to 300 ft. Let's say for a max bottom time of 10 minutes - just go to 300 ft, hang out there for 10 min, then head back. I am not interested in a recipe and I won't be trying this on my own. I'd be curious in a sketch based upon healthy divers with decent SAC rates. For example, would you likely have doubles plus stage bottles? Eight bottles per diver? Trimix? Deco obligations totaling eight hours? Support divers?

Again, please don't waste too much time. I just want to see how very different a DIR approach would be from a "bounce dive."

Been awhile since I've done these exposures on OC so I'm trying to remember what I did then and what the OC guys were doing this past June when we were in Halifax. We would have 10/70 backgas in double 104s plus an 80 of backgas. A 40 of 120' deco, a 40 of 50' deco and a 40 of 100%. Bottom time (timer started at 70') of around 17 minutes. Runtime of around 90 minutes. We used support divers on our Nova Scotia trips back 5-10 years ago. These days...not so much.

 

[nadwidny]

I posted the v planner profile for a ten minute 300 ft dive. That was on air. Not having gone that deep yet due to not having full trimix training I can't give specifics. But as has already been noted a proper dive to that depth would likley involve at least two travel gasses- say a mix good to 130, then a switch to one good to 210 or so, a bottom mix, and the appropriate deco which could be 2 or 3 mixes.

In addition a proper dive to that depth would also involve the use of safety divers to bring deco mixes if necessary, carry used travel gas bottles, and perhaps even provide snacks and drinks to the divers doing the deco.

A perfect example of how you can't learn to dive off the internet. Travel gasses?? Puh-lease. 2 travel gasses?? Stick to what you know. You're just cluttering up the thread with your wild ass guesses on how a dive like this would be done.

 

[USVet96]

Been awhile since I've done these exposures on OC so I'm trying to remember what I did then and what the OC guys were doing this past June when we were in Halifax. We would have 10/70 backgas in double 104s plus an 80 of backgas. A 40 of 120' deco, a 40 of 50' deco and a 40 of 100%. Bottom time (timer started at 70') of around 17 minutes. Runtime of around 90 minutes. We used support divers on our Nova Scotia trips back 5-10 years ago. These days...not so much.

Forgive my ignorance nad..., but when you say "a 40 of 120' .... a 40 of 50', etc" what exactly does that mean.

Trying to understand.

Thank you

USVet

 

[ianr33]

Forgive my ignorance nad..., but when you say "a 40 of 120' .... a 40 of 50', etc" what exactly does that mean.

Trying to understand.

Thank you

USVet

40 cu feet of a gas that will be first breathed at 120 feet, 40 cu feet of gas that will be first breathed at 50'

As this is the DIR forum I suspect nadwidny may have made a mistake? (Is such a thing even possible? ) Normal deco gas would be 50% O2 that can be breathed at 70'

 

[Dsix36]

Forgive my ignorance nad..., but when you say "a 40 of 120' .... a 40 of 50', etc" what exactly does that mean.

Trying to understand.

Thank you

USVet

a 40 of 120' deco means a 40 cubic foot tank of gas that is used for deco at a depth of 120 foot (not sure about DIR standard gasses, 35/25?)

a 40 of 50' means a 40 cubic foot tank of gas for breathing at 50 foot (50% or 50/25?)