how deep max. when diving solo?

[Kevrumbo]

I am not picking on you. I enjoy your posts.

A safety stop is not a mandatory stop.

The 19cf is more than enough for me to do a standard ascent and a optional safety stop. It is unlikely the emergency will occur at the end of the dive with accumulated maximum saturation. It could but it could also occur at any point in the dive. Specifically for dives beyond 100 feet I may go with a 30cf, maybe. My SAC is quite low so giving me a little flexibility the Air Hogs do not have.

N

Yeah but your breathing SAC rate may be better than the OP (Taliena) so a 19cf/2.7L pony may not be enough --point is Taliena has to do the practical calculation objectively now for himself --like in post 92-- after reading all the different accounts & anecdotes in reply to his general inquiry:

How deep do you dive as max. solo? and the max. decotime?

 

[Omisson]

Dive sidemount - solution complete.

 

[scubadada]

I am not picking on you. I enjoy your posts.

A safety stop is not a mandatory stop.

The 19cf is more than enough for me to do a standard ascent and a optional safety stop. It is unlikely the emergency will occur at the end of the dive with accumulated maximum saturation. It could but it could also occur at any point in the dive. Specifically for dives beyond 100 feet I may go with a 30cf, maybe. My SAC is quite low so giving me a little flexibility the Air Hogs do not have.

N

As Nemrod points out, some us have put thought into our redundant gas supply. For me to spend a minute at 130 feet, make an ascent to 15 feet at 30 ft/min, make a 3 min SS, and ascend to the surface, all at twice my normal SRMV, would take me just under 17 cu ft of gas.

I would not likely spend the time at depth in this situation, there is some flexibility in the ascent, and the SS is optional. Still, nice to know what my redundant gas represents, just in case. I would advise divers to make these simple calculations, using their own air consumption.

I rarely dive solo past about 100 feet, but have occasionally dived to recreational limits. I generally do not do solo deco, rarely, just a few minutes

 

[SM Beaton]

I had an awesome solo 60m night dive the other day. Steep slope that dropped down to 70m so I couldnt drop to far away if I had buoyancy problems. Redundant everything. This also meant I could finish deco with half my remaining back gas being lost. I felt pretty conservative looking at my plan.

 

[Germie]

Done deep trimix dives solo, caves, wrecks, shallow lakes, oc with twinset, ccr, sidemount. There is never a must in solodiving, never a must in depth or what environment. Just do what you like to do and where you feel safe.

A 3L pony bottle is not enough in a stressfull situation in ow when you come from 30m depth. I don't talk about overhead, because then really different calculations must be made.

 

[AfterDark]

Yeah but your breathing SAC rate may be better than the OP (Taliena) so a 19cf/2.7L pony may not be enough --point is Taliena has to do the practical calculation objectively now for himself --like in post 92-- after reading all the different accounts & anecdotes in reply to his general inquiry:

A couple of facts for you; once upon a time a safe ascent rate was 60FPM. A rate I used for more than 20 years. The old rule of thumb "raise no faster than your smallest bubbles" is about 60FPM which is where it came from. The second is a personal fact, at the tender age of 17 with 1 year of diving experience, diving a double hose regulator that failed closed during buddy separation I was forced to make a free ascent, a blow and go, CESA from 70FSW. My rate exceeded 60FPM I'm sure. My point is a 19 cuft bottle is enough from any "rec" diving depth to get a diver to the surface non stop, safety stops are optional. After 44 years I've never been bent not once diving the way I dive.

I don't disagree that gas planning is paramount in planning any dive and provisions must be made to be able to get you and your buddy to the surface safely but in a real emergency a SS is just not going to help the situation.

We can play what if, what if you have a panicked diver on your hands you going to hold him at 15' for a SS? Or if you or a buddy is bleeding from nose, mouth or ears or has a deep wound somewhere? What if a diver is convulsing? How does a SS improve these scenarios? In real life during an emergency the rules get stretched. Lives are saved.

 

[Kevrumbo]

A couple of facts for you; once upon a time a safe ascent rate was 60FPM. A rate I used for more than 20 years. The old rule of thumb "raise no faster than your smallest bubbles" is about 60FPM which is where it came from. The second is a personal fact, at the tender age of 17 with 1 year of diving experience, diving a double hose regulator that failed closed during buddy separation I was forced to make a free ascent, a blow and go, CESA from 70FSW. My rate exceeded 60FPM I'm sure. My point is a 19 cuft bottle is enough from any "rec" diving depth to get a diver to the surface non stop, safety stops are optional. After 44 years I've never been bent not once diving the way I dive.

I don't disagree that gas planning is paramount in planning any dive and provisions must be made to be able to get you and your buddy to the surface safely but in a real emergency a SS is just not going to help the situation.

We can play what if, what if you have a panicked diver on your hands you going to hold him at 15' for a SS? Or if you or a buddy is bleeding from nose, mouth or ears or has a deep wound somewhere? What if a diver is convulsing? How does a SS improve these scenarios? In real life during an emergency the rules get stretched. Lives are saved.

Fair and good account, your own personal anecdote of a CESA contingency, and your proposal that 19cf/2.7L bottle is adequate & safe enough supply to surface compared to your "blow & go" from 70'/21m. Miy point is again, the OP (Taliena) still has to do the gas planning for his own dive application, breathing rate and depth range. Who knows, 19cf might be the right amount but has to confirm that figure for himself.

And as for a "what if" scenario with a victim (e.g. bleeding or unconscious/full arrest diver contingency etc), a situation where you must get the diver surfaced ASAP to render aid -obviously you must abort the safety stop. I agree. Even so, I would still figure into the gas plan for a Safety Deco Stop although this one particular scenario would actually preclude performing it. . .

 

[DaleC]

Sure, fine . . . a 19cf/2.7L emergency bottle will get you to the surface from 30m: ascend at a faster rate between 9m to 18m per min to 5m depth and hold a safety stop for as long as you have any remaining gas left. However, any delay though during the ascent and you may not have any margin gas left to perform any safety stop. . .

But I prefer the slower ascent more conservative approach of post#92 above. . .

That's funny. GUE's take is 40cuft for two people from 100'. This includes min deco and rounding up. Divided in half that's 20cuft. Is UTD doing something more conservative than that.

 

[Kevrumbo]

That's funny. GUE's take is 40cuft for two people from 100'. This includes min deco and rounding up. Divided in half that's 20cuft. Is UTD doing something more conservative than that.

No not really . . .again the gas planning methodology is similar for both Buddy & Solo Diving (Solo you're obviously planning for a redundant "Rock Bottom" pony bottle amount of breathing gas for only yourself), but with arbitrary parameters such as ascent rates, safety stops etc as conservative -or just "radical blow & go CESA"- as you want it.

Recap and refer again to post #92

 

[DaleC]

I looked at post #92 and I don't understand why you would imagine you need to do 1 minute stops all the way up from 100ft (30m). GUE's min deco calls for ascent to 1/2 max depth and then 1 minute stops. For non GUE/UTD folk the usual conservative plan is 1 minute at depth to solve problems, ascent at 30'/min, 3 minute safety stop. To make it simple you need three areas of calculation: 1.Time at depth. 2. Travel time. 3. Time at stops.
That looks like this with an assumed SAC of 1cuft:



1 minute at depth: 1X4atm = (4)

100ft divided by a 30ft/minute ascent rate = 3.3 minutes travel time at an average depth of 50' [2.5atm]. 3.3 X 2.5 = (9) [8.25 rounded up]

3 minute safety stop at 15' [1.5atm] = (5) [4.5 rounded up]

4 + 9 + 5 = 18cuft.




Another way to look at it is:

1 minute at depth: 1X4atm = (4)

3 minutes safety stop at 15' [1.5 atm] = (5) [4.5 rounded up]

travel is calculated at the highest atm value/minute

1 minute at 2 atm [travel between 0-33'] = (2)
1 minute at 3 atm [travel between 33-66'] = (3)
1 minute at 4 atm [travel between 66-99'] = (4)


4 + 5 + 2 + 3 + 4 = 18cuft.

* edited for corrected atm's and rounding up