CRDiver
Contributor
JS1scuba:
Excellent points Joel. Nice to see truly legitimate tech divers weigh in once in awhile.
Solo diving and back up gear.
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Excellent points Joel. Nice to see truly legitimate tech divers weigh in once in awhile.
"The stock 13 / 14 / 19 cuft pony provides sufficient gas to ascend from 100 fsw and then do a decent saftey stop. It's not for horizonal swimming while at depth."
Yes, I agree and thankyou for the post.
If I were on a 13cf poney and my primary source failed I would immediantly begin an ascent on my poney. I feel confident this is enough air for even 120 feet but certainly 100 feet.
Three old time diving rules
there are certainly exceptions especially in tech and deep diving and advanced diving endeavors)
1) Do not dive deeper than twice your free diving depth. Example, if you can free dive 20 feet then 40 feet is your max scuba depth!
2) Do not swim out bound farther from your exit point than you can swim comfortably on the surface in a pool with full gear.
3)Rule of 1/3s. One third outbound, one third inbound (back on the boat deck or hanging on the safety line for a safety stop or sitting on the beach), last one third is emergency reserve.
One third of an 80cf bottle (single tank diving) is approx 25cf so a 20(ish) cf bottle should do the trick for your emergency reserve to 130 feet but certainly 100 feet in an OW and No Decompression profile following rule number three. This assume an immediate abort of the dive and no overhead obstructions. If one were of the mind to complete the dive then clearly you need another one third so now we are talking about 40/50 cf and at this point why not just a double 72/80/whatever your using. I guess what I am saying there is that once the poney is a full size tank nearly why fool around --just go ahead and do a double rig with all the trick stuff but in my opinion that is overkill for most normal OW, no deco, sport diving. There is more than one way. N
Yes, I agree and thankyou for the post.
If I were on a 13cf poney and my primary source failed I would immediantly begin an ascent on my poney. I feel confident this is enough air for even 120 feet but certainly 100 feet.
Three old time diving rules
there are certainly exceptions especially in tech and deep diving and advanced diving endeavors)1) Do not dive deeper than twice your free diving depth. Example, if you can free dive 20 feet then 40 feet is your max scuba depth!
2) Do not swim out bound farther from your exit point than you can swim comfortably on the surface in a pool with full gear.
3)Rule of 1/3s. One third outbound, one third inbound (back on the boat deck or hanging on the safety line for a safety stop or sitting on the beach), last one third is emergency reserve.
One third of an 80cf bottle (single tank diving) is approx 25cf so a 20(ish) cf bottle should do the trick for your emergency reserve to 130 feet but certainly 100 feet in an OW and No Decompression profile following rule number three. This assume an immediate abort of the dive and no overhead obstructions. If one were of the mind to complete the dive then clearly you need another one third so now we are talking about 40/50 cf and at this point why not just a double 72/80/whatever your using. I guess what I am saying there is that once the poney is a full size tank nearly why fool around --just go ahead and do a double rig with all the trick stuff but in my opinion that is overkill for most normal OW, no deco, sport diving. There is more than one way. N
ArcticDiver
Contributor
Nemrod:"The stock 13 / 14 / 19 cuft pony provides sufficient gas to ascend from 100 fsw and then do a decent saftey stop. It's not for horizonal swimming while at depth."
Yes, I agree and thankyou for the post.
If I were on a 13cf poney and my primary source failed I would immediantly begin an ascent on my poney. I feel confident this is enough air for even 120 feet but certainly 100 feet.
Three old time diving rules
1) Do not dive deeper than twice your free diving depth. Example, if you can free dive 20 feet then 40 feet is your max scuba depth!
2) Do not swim out bound farther from your exit point than you can swim comfortably on the surface in a pool with full gear.
3)Rule of 1/3s. One third outbound, one third inbound (back on the boat deck or hanging on the safety line for a safety stop or sitting on the beach), last one third is emergency reserve.
One third of an 80cf bottle (single tank diving) is approx 25cf so a 20(ish) cf bottle should do the trick for your emergency reserve to 130 feet but certainly 100 feet in an OW and No Decompression profile following rule number three. This assume an immediate abort of the dive and no overhead obstructions. If one were of the mind to complete the dive then clearly you need another one third so now we are talking about 40/50 cf and at this point why not just a double 72/80/whatever your using. I guess what I am saying there is that once the poney is a full size tank nearly why fool around --just go ahead and do a double rig with all the trick stuff but in my opinion that is overkill for most normal OW, no deco, sport diving. There is more than one way. N
Just curious, from 100-130 fsw what ascent rates would you use? How many stops and at what depths? For this question lets' use the seas I was diving in last week; 8 foot seas with 18kt winds gusting to 25kt or so.
ArcticDiver:
I intend not to argue (lol--freindly chuckle) with a person about a specific dive I was not present at. The Navy Tables--which I have used since I was 12yo allow a direct ascent from 130 feet after a max no deco bottom time of 10 minutes. Such an ascent at 60 fpm would take just over 2 minutes and then I would allow a few minutes safety stop at 10 feet. From 100 feet after a max. no deco time of 25 minutes an ascent of approx 1:45 minutes duraration. Have done this more than once. I typically use a 10% safety margin--I don't use computers much and when I do I back them up with a watch and the tables so call me old school.
If you have a different method, fine, I am sure it is a fine approach, just not mine. You may be confusing my statement with the one I quoted--copy and paste.
I also stated a normal OW dive--if you had 8 foot seas that is likely not all that normal for many people and in most cases most boats will not go out in such condtions and I certainly won't take my boat out purposely in that condition so as a hypothetical--I would not dive those conditions SOLO. If the anchor line or anchor set gave way--then what? Well, I guess someone was on the boat to tend it while you were down and about.
I suppose if you are at 100 feet then you can free dive 50ish feet per rule number 1 and in such case then an ascent from 100 feet with 20 cf in the bank should be a cake walk. These rules are not mine--they have been around a long time---they are quoted in part in the book Solo Diving by Robert Maier. These are not end all, cover all conditions and no exception rules but it makes sense when solo diving not to push the envelope. In my present and aging condtion I expect 50 feet freedive would be a strain for me so I would probably limit my solo diving to 80feet, maybe 100 feet for the time being, maybe less.
Let me ask you--how much air do you need to ascend vertically for two minutes? If you are doing intentional deco dives then you are beyond the profile I was discussing. N
ArcticDiver
Contributor
Nemrod:
No arguement intended just trying to understand what to me is a new set of criteria and how I might apply them to my diving.The diving conditions I mentioned were those on the Upper Keys last week. The boat captain said they are pretty common this time of year. I found them diveable with on real problem, as did all the rest of the folks on the boat.
Definition: Solo diving does not mean solo transportation to and from the dive site.
In comparing rates of ascent, your's is a bit faster than mine. I use <60fpm deeper than 60fsw and <30fpm for anything shallower than that. The Deco Stop we call a "safety stop" is 3-5 minutes. Sea states permitting it often takes me 2 minutes to make it from my "safety stop" to the surface. For a deep dive I usually make a halfway stop for one minute. So, if I am to make a normal ascent from 100fsw I need gas for 10 minutes. That is about 6cf plus reserves for emergencies, sea state, etc.
You choose to go up faster. Since SCUBA is an art based on science and you are the artist that is your choice; no arguement. Certainly the Navy Tables are more aggressive than some others. For example my new Nitek uses the Buhlmann ZH-L16 which is Much more conservative than the Navy Tables. Which is correct, ir is any? Such is the source of much heated discussion.
"No arguement intended just trying to understand what to me is a new set of criteria and how I might apply them to my diving."
Sorry Articman if I was a smart alec---lol---thanks.
Yeah, it sounds like it was a preat dive, wish I was there.
As to tables, I gave up following all the new flavors and went back to the Navy Tables and as I said with about a 10% margin. I try to ascend at 60FPM and I do make safety stops.
The computers do allow increased bottom times obviously under some conditions.An example, a few years ago I did a dive to 140 feet out of Jupiter. I planed my dive for 140 feet which is 10 minutes bottom time (9min with safety margin). But, since I did most of the dive at around 100 feet and only bounced 140 feet the computer gave me about 5 minuntes more BT than the tables, the tables used the way I was taught assume a square profile, 140 feet is 10 minutes period. Yes, I am aware that some people use different tables and step profile their tables--I don't. If I need that then a computer is more sense. I don't have anything really agaisnt computers, just generally don't use them and they do fail from time to time. I probably need to buy one, of course, my main beef with them is that they are obsolete as soon as it comes out of the box and they have so many different programs. I am old fashioned, I like standardization. N
Sorry Articman if I was a smart alec---lol---thanks.
Yeah, it sounds like it was a preat dive, wish I was there.
As to tables, I gave up following all the new flavors and went back to the Navy Tables and as I said with about a 10% margin. I try to ascend at 60FPM and I do make safety stops.
The computers do allow increased bottom times obviously under some conditions.An example, a few years ago I did a dive to 140 feet out of Jupiter. I planed my dive for 140 feet which is 10 minutes bottom time (9min with safety margin). But, since I did most of the dive at around 100 feet and only bounced 140 feet the computer gave me about 5 minuntes more BT than the tables, the tables used the way I was taught assume a square profile, 140 feet is 10 minutes period. Yes, I am aware that some people use different tables and step profile their tables--I don't. If I need that then a computer is more sense. I don't have anything really agaisnt computers, just generally don't use them and they do fail from time to time. I probably need to buy one, of course, my main beef with them is that they are obsolete as soon as it comes out of the box and they have so many different programs. I am old fashioned, I like standardization. N
ArcticDiver
Contributor
Nemrod: I guess it falls back on a truism: If people want to communicate they will mutually express their thoughts until they succeed. On the other hand many people, including on this Board, write more to Impress than to Express. Glad to see neither of us are in the latter category.
Can I sum your rules up in one statement? "Always dive solo in conditions where escape to the surface is feasible for the diver."
Your rules set out some parameters to determine what those conditions might be.
Have I got it right, or at least close?
Can I sum your rules up in one statement? "Always dive solo in conditions where escape to the surface is feasible for the diver."
Your rules set out some parameters to determine what those conditions might be.
Have I got it right, or at least close?
"Your rules set out some parameters to determine what those conditions might be.
Have I got it right, or at least close?"
Yes, Articman, I think that is the purpose of those rules--to allow an escape or to maintain one's self within an envelope of safety. Unfortunately, I cannot claim these rules, they are passed on from an old instructor and I have seen them in print as well in various forms. See the book "Solo Diving" by Robert Von Maier but I don't think they belong to him either because as I said, I think they go back to the "frogman days" . Obviously people routinely surpass these parametrs ---reading about rebreather divers at 250 feet etc--wow. The only reason I realy brought them up is that when you/I are solo we really may be totally own our own and running out of Go power half way back to shore or almost making the surface after an OOA or equipemnt failure just does not cut the mustard so to speak cuz there ain't gonna be anyone to help us out thus I think that solo and conservative go hand in hand. N
Have I got it right, or at least close?"
Yes, Articman, I think that is the purpose of those rules--to allow an escape or to maintain one's self within an envelope of safety. Unfortunately, I cannot claim these rules, they are passed on from an old instructor and I have seen them in print as well in various forms. See the book "Solo Diving" by Robert Von Maier but I don't think they belong to him either because as I said, I think they go back to the "frogman days" . Obviously people routinely surpass these parametrs ---reading about rebreather divers at 250 feet etc--wow. The only reason I realy brought them up is that when you/I are solo we really may be totally own our own and running out of Go power half way back to shore or almost making the surface after an OOA or equipemnt failure just does not cut the mustard so to speak cuz there ain't gonna be anyone to help us out thus I think that solo and conservative go hand in hand. N
ArcticDiver
Contributor
Super!
From my experience solo well off the road system in Alaska I have discovered that each person has their own Comfort Zone. Some folks won't use a gas axe(chainsaw to some) when by themselves while others, like me, won't climb on the roof. It all depends on a very real thing called Risk Management.
The only two things that bite a thinking person are The Unk-Unks and Being Human. The Unk-Unks are those things that are not only Unknown; you don't know they are Unknown. Risks whose identity and magnitude are Known can be compensated for. Risks whose identity is known but whose magnitude is Unknown can be allowed for. But Unk-Unks are real bears because you don't even know that you don't know. A bit confusing, but think a minute and understanding will come.
The other real danger is the occasional demonstration of Humanity. That is where our human lack of perfection leads us to make a mistake. If the mistake is survived a really good War Story results. If not, then it is often said: What a Dumb Bunny; I wouldn't have made that mistake. Sure......as if anyone is immune to such demonstrations of humanity.
From my experience solo well off the road system in Alaska I have discovered that each person has their own Comfort Zone. Some folks won't use a gas axe(chainsaw to some) when by themselves while others, like me, won't climb on the roof. It all depends on a very real thing called Risk Management.
The only two things that bite a thinking person are The Unk-Unks and Being Human. The Unk-Unks are those things that are not only Unknown; you don't know they are Unknown. Risks whose identity and magnitude are Known can be compensated for. Risks whose identity is known but whose magnitude is Unknown can be allowed for. But Unk-Unks are real bears because you don't even know that you don't know. A bit confusing, but think a minute and understanding will come.
The other real danger is the occasional demonstration of Humanity. That is where our human lack of perfection leads us to make a mistake. If the mistake is survived a really good War Story results. If not, then it is often said: What a Dumb Bunny; I wouldn't have made that mistake. Sure......as if anyone is immune to such demonstrations of humanity.
Squalus
The Good Humor Guy
Fire_medic_RescueDiver:
What SSI course is that?
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