Larger Tanks for deep dives (100ft)

[Troutmaster]

As a very wise instructor of mine once said, "You can fix bent; you can't fix drowned." I'll take extra gas, any day. In fact, I routinely dive with a lot more tank and a lot more gas than I need for any given dive. It gives me a warm, fuzzy feeling. (It's one place where I'm not into minimalism!)

+3

I have never seen any diver have any ill effect from getting on the boat with too much back gas left over. Plenty of divers have never gotten back on the boat at all with too little gas.

 

[UCFKnightDiver]

Not sure I follow the logic of that. "Extra air" has sure as hell got to be safer than "insufficient air". Yes, more air would, theoretically, allow a careless diver to rack up a deco obligation before they ran out of gas. But surely the assumption must be the trained diver will monitor depth and time, and not just their SPG? A good diver can get into deco at 60 feet with an aluminum 80 - it doesn't follow that people should wear smaller tanks just to force them back to the surface earlier.

My own view is that it will be a rare thing that too much gas constitutes a safety problem.

You would have to have a SAC rate of .39 to do this, to be honest I don't know too many if any that have this... I'm pretty sure I don't, mine hovers around a .5 usually.

What is "recreational penetration"? You mean not going past the light zone? Sorry, I just haven't heard that term before.

Also I am interested to hear how often 1/6ths is taught. I have always been taught rule of thirds, in wreck + cavern training and have not heard (other than posts here) of people being taught to dive 1/6ths. I'm a recreational diver too.

As to Saspotato, NACD/NSSCDS Cavern the limit is 200 ft linear penetration and 1/3rd of singles not sure about NAUI, but I assume it's similar, the Intro to Cave rating is by gas 1/6th of doubles or 1/3rd for singles for NACD/NSSCDS.

 

[sterlingMarineService]

As I'm reading here it says you want to sling 1/3 the gas that's on your back? Why 1/3


Also someone said they sling an al80.... That seems huge?! What would you use it for? Longer bottom time?!

 

[UCFKnightDiver]

As I'm reading here it says you want to sling 1/3 the gas that's on your back? Why 1/3


Also someone said they sling an al80.... That seems huge?! What would you use it for? Longer bottom time?!

Yes, as a stage.

 

[Rhone Man]

You would have to have a SAC rate of .39 to do this, to be honest I don't know too many if any that have this... I'm pretty sure I don't, mine hovers around a .5 usually.

Sorry, you're right - my original post was badly phrased. But I think you get the gist of what I was trying to convey.

 

[DCBC]

It depends upon your consumption rate and the dive plan, but I don't think you would go wrong with a HP130 with a 40 pony. With a know high consumption rate there's no such thing as too much gas.

 

[zaberman1]

What is "recreational penetration"? You mean not going past the light zone? Sorry, I just haven't heard that term before.

Also I am interested to hear how often 1/6ths is taught. I have always been taught rule of thirds, in wreck + cavern training and have not heard (other than posts here) of people being taught to dive 1/6ths. I'm a recreational diver too.

Recreational penetration is probably a poor choice of words but is more often then not used in intro to wreck diving courses. 1/3 is always taught on a single but 1/6th is used when using double tanks to get the 1/3 of your single. Any cave instructor from NACD, NSS, or the others will tell you 1/6 on doubles for Cavern and Intro. 1/3 is always calculated for recreational wreck penetration (yea not past the light zone, no restrictions, 1/3 on singles, etc) but is adjusted when using doubles.

 

[zaberman1]

1. Why is a 'good diver' defined as one whose SAC rate is good?

2. All the cave agencies have a linear limit for their cavern courses and wreck diving agencies do too. Cave: 200ft linear and horizontal...Wreck: 130 ft linear and horizontal

 

[Rhone Man]

Recreational penetration is probably a poor choice of words

I don't know, but it sure as hell sounds more interesting than wreck diving...!

 

[Rhone Man]

1. Why is a 'good diver' defined as one whose SAC rate is good?

Sorry, I already apologised for that. I meant a diver with a really low SAC rate (rather than a 'good' diver) could hit the NDLs at 60 feet with an Al80. I was falling into the same trap as others as implicitly assuming low SAC = better diver, but I acknowledge that is not correct.