DaleC
Contributor
I was reminded of this old thread. Not a bad discussion at all: http://www.scubaboard.com/forums/dir/268825-dir-process-system.html
Couple questions on a pony bottle for bail out
- Thread starter Sonic04GT
- Start date
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mick allein III
Contributor
My two cents. I have both a 19 and a 40. I generally use the 19 on shallow dives with buddies I know well. Deeper dives or with buddies I don't know I use the 40. Quite honestly in the water I notice no difference between the two . My reccomendation would be to buy a 40cf pony.
kwinter
Contributor
Well at least the thread got back on to pony bottles.
We are talking about a recreational diver using a single 80. You are recommending that his redundant supply for an emergency ascent should be fully one-half of his primary supply. And you don't think that's overkill just because you don't mind slinging it?
I ran a schedule for a rebreather dive to 100 feet at 1.2 with a 50 minute bottom time, followed by bailing out onto air for an emergency ascent. It requires over 30 minutes of decompression and still would use less than 40 cf of air. Why would you ever need a 40 cf pony bottle for a simple rec dive?
kwinter
Contributor
Not sure what you saw in my post that would make you doubt the schedule. You really are a first class a-hole, aren't you?
EDIT: Greg_Vic_Diver seems to have edited his last post to remove the snotty comments about doubting that I had actually run the schedule. Maybe there is some hope for him.
EDIT: Greg_Vic_Diver seems to have edited his last post to remove the snotty comments about doubting that I had actually run the schedule. Maybe there is some hope for him.
Not sure what you saw in my post that would make you doubt the schedule. You really are a first class a-hole, aren't you?
Not doubting your schedule, but would like to see the calcs...besides don't you think that would be a better use of a Pony Bottle thread?
---------- Post added July 30th, 2014 at 09:55 PM ----------
What SAC rate are you assuming?
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mrdre
Contributor
kwinter
Contributor
Now you have me even more confused. Exactly what calculations would you like to see since you're not satisfied with V-Planner or Multi-Deco.
Consider a diver at recreational depth doing a no deco dive. Even at an ascent rate of 60 fpm it would only take 2 minutes to ascend to 20 feet. And even allowing for a 3 minute safety stop despite having a catastrophic failure that caused the bailout in the first place, it is a total of 5 minutes at an average depth of about 33 feet (2 ATA). What kind of RMV do you suspect this person to have that would require anything close to 40 cubic feet of gas for 5 minutes at an average depth of 33 feet? I guess it would have to be the same guy who makes a dive to 33 feet with an aluminum 80 and runs out of gas in 10 minutes. Know anyone like that?
---------- Post added July 31st, 2014 at 02:12 AM ----------
A 24 minute dive at 130 feet is not a no-deco recreational dive. In fact it requires almost an hour of decompression. And it would still require only 2 minutes to ascend to 20 feet if he had to blow off his deco stops from 70 to 20 feet.
I guess I just don't get your point.
Consider a diver at recreational depth doing a no deco dive. Even at an ascent rate of 60 fpm it would only take 2 minutes to ascend to 20 feet. And even allowing for a 3 minute safety stop despite having a catastrophic failure that caused the bailout in the first place, it is a total of 5 minutes at an average depth of about 33 feet (2 ATA). What kind of RMV do you suspect this person to have that would require anything close to 40 cubic feet of gas for 5 minutes at an average depth of 33 feet? I guess it would have to be the same guy who makes a dive to 33 feet with an aluminum 80 and runs out of gas in 10 minutes. Know anyone like that?
---------- Post added July 31st, 2014 at 02:12 AM ----------
A 24 minute dive at 130 feet is not a no-deco recreational dive. In fact it requires almost an hour of decompression. And it would still require only 2 minutes to ascend to 20 feet if he had to blow off his deco stops from 70 to 20 feet.
I guess I just don't get your point.
Need assumed SAC rate, time to deal with issue at depth, ascent rate to first stop, time at second stop etc..
Myself, I usually just manually do the math and I find it helps it planning (takes like 1-2mins)
Myself, I usually just manually do the math and I find it helps it planning (takes like 1-2mins)
kwinter
Contributor
My bottom SAC is about 1.0. Deco SAC is about 0.5 and working SAC is about 2.0 for very short bursts. Double those since average depth in the example is 33 feet. I'm not sure what "time to deal with issue at depth" means since you would just deploy the pony second stage and immediately start to ascend. Ascent to first stop is also the only stop. There is no second stop when we are talking about no deco recreational diving.
Or are you guys confusing a pony bottle with a deco cylinder?
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