Larger Tanks for deep dives (100ft)

[salub2007]

HI,

Planning a few deeper wreck dives this summer.
Would like to have a single tank that can have
superior bottom time over what I have now. using a HP steel
100. I am thinking of the Faber 118 blue steel. Any thoughts..
I am 250 pounds and consume air very fast at depth, but it has gotten
much better in the past year or so. Still would like the safety of extra air.

I am also looking to carry a pony on a pony bracket attachment. What size would
you need with a 118? I am new to diving with only 70 dives. I am however in my advanced training with SSI, and taking the deep course this summer. Would like to
get equipped before the class begins. Again I require more air than most..

Thanks, and Happy ST Patty's Day!

Salub2000
MJ

[H2O 70]

Worthington has their HP 130's. I've been happy with mine.

I would sling an AL40 with those tanks.

The reason I went with an AL40 was it was very close to 1/3 my back gas and as I moved into tec diving it makes for a good deco bottle.

[it_mike]

Have you considered independent doubles? There are several home-made ways to attach them to a backplate, or you could go with the Dive-Rite or OMS solutions. This would give you an extra HP100 and choices based upon the dive ahead.

[TSandM]

Another vote for the HP130s, if you have a shop that can provide 3442 fills. They're nice tanks from a dimension standpoint and trim out well, and you'll run into deco or get cold before you run out of gas :)

[Buoyant1]

I've been using steel 119's and have had great luck with them (and I'm not exactly a small person) I'm considering doubling them at some point this season, but have had no problems running low on gas as singles. I also sling an al40 for contingency.

130's as someone mentioned are the same size and I think weigh slightly more. You can't go wrong with those sizes.

Good luck on your purchase!

[emoreira]

I dream with an HP130.
There is no rental steel tanks, only those AL80.

[PfcAJ]

I vote for more shallow diving till you are better with your gas consumption.

[kanonfodr]

I will throw in another vote for the HP130s, great tanks! Loads of gas and trim out very nicely. I dive LP95s regularly and they behave very similarly.

Peace,
Greg

[Rhone Man]

I vote for more shallow diving till you are better with your gas consumption.

I would never want to tell somebody what they ought to, but I would say that if/when you go deeper, remember that it is all the more important to go slow and stay relaxed. CO2 buildup and gas consumption are a !*#$%@ at depth if you start working too hard.

ADDITIONAL: Don't be tempted into the evils of skip breathing to reduce your gas consumptions. Especially not at depth.

[v--Locke--v]

use the hp 100, sling an al80

[H2O 70]

use the hp 100, sling an al80

Just curious, but why do you suggest this?

As pony tank is there for a worst case scenario. It is a bail out tank. It isn't part of the gas plan. Well, shouldn't be part of the gas plan.

So the HP100 isn't going to help out with his need/want/desire for more back gas and slinging an AL80 is a big tank to sling. He is carrying 2/3 of his back gas in a pony?

[svs]

It depends of how much air you have left by the time you hit NDL. If you still have around 1000, you don’t need another tank. Pony though will be still helpful for other reasons. Minimal size depends of the amount of air you need to ascent safely from say 130ft.

[FireInMyBones]

I love my HP 120. Buying double 130s this fall. I sling a 40.

[fnfalman]

I like my Faber HP120 M-series. Same buoyancy characteristics as my Faber HP100 M-series but more gas.

[Meng_Tze]

I vote for more shallow diving till you are better with your gas consumption.

To add to that. You should know/be able to assess what tank you would want. How deep, how long, what profile, what reserves. Combine this with consumption, you should get an idea of what to carry.

[ianr33]

To add to that. You should know/be able to assess what tank you would want. How deep, how long, what profile, what reserves. Combine this with consumption, you should get an idea of what to carry.

Also bear in mind you need to figure your higher than normal consumption rate when calculating gas reserves for a buddy team.

Not much use you having a huge tank if it has just freeflowed and emptied. If your buddy in that situation is a tiny girl using an Al 63 then you could both be in a world of hurt.

[UCFKnightDiver]

Just curious, but why do you suggest this?

As pony tank is there for a worst case scenario. It is a bail out tank. It isn't part of the gas plan. Well, shouldn't be part of the gas plan.

So the HP100 isn't going to help out with his need/want/desire for more back gas and slinging an AL80 is a big tank to sling. He is carrying 2/3 of his back gas in a pony?

Who said anything about a pony?

[H2O 70]

Who said anything about a pony?

Actually the OP did.


I am also looking to carry a pony on a pony bracket attachment. What size would
you need with a 118?

[Puffer Fish]

I'm your size and have Faber 100's, 117's and 133's....my default tank for deeper diving is the 117's...

Comparing Worthington versus Faber FX series... some sizes favor Worthington, and some Faber, the 117 weights in at 3 lbs less...and gear weight can add up.

There is the thinner 120's..which fit easier in boat racks, but are really tall, and much harder to find sales on...

I have a fairly low SAC rate (typically between .4 and .5cf/min) for a big guy and even matching up nitrox with the depth, normally come back at near the NDL limits with around 1,500 psi in my tank. I would think it would work reasonably well.

What about doubles.. well you have the cost, the cost of filling and the pain of dragging the things around..when I taught at a shop... I used doubles...now I like the lower weight, and ease of transport.

Pony... well the lightest reasonable tank is a 20 (have one)... but it is easy to make an arguement for bigger (depending on it's use), so a 30 (have one) or a 40 could be done. If you only have one, would suggest the middle path and get a 30. There is no reasonable no-deco or short deco that one cannot do with a 30...and both the size and weight are reasonable.

[Sas]

I dream with an HP130.
There is no rental steel tanks, only those AL80.

Locally to me they pretty much only rent steel (HP100s) unless you specifically request otherwise.

I use a HP100. That tank lasts til NDL with air or nitrox diving down to 30m. But if you have high air consumption just get something bigger than that, but that is still comfortable to dive with and cart around.

To calculate what pony size you need, work out your SAC and your stressed SAC and see how many litres you would need to get to the surface in an emergency. Get a pony that holds that amount (or more ;)). I am not sure how the mounting system works but you can always sling a pony.

Re doubles, they are a lot of expense and there are other issues to consider with them. If you are not going to dive deeper than 30m I am sure a single + a pony is suitable.

[UCFKnightDiver]

Actually the OP did.

The person you quoted though said to sling an 80, not necessarily insinuating that it was to be used as a pony.

[SDE Dennis]

I love having doubles on dives over 100 ft. from boats.

No need to switch tanks, plenty of reserve air. (they like you to have 1/3 out 1/3 return and 1/3 for acent). With doubles you don't lose the left over gas from the first dive. You can also set them up independly for redundancy.

btw I have double 120's which I can seperate as singles.

[H2O 70]

The person you quoted though said to sling an 80, not necessarily insinuating that it was to be used as a pony.

So you think they were suggesting they double up a HP100 with an AL80 or they just simply sling an AL80 and plan it as part of their gas plan?

I was assuming since the OP asked about a pony that the 2nd poster was suggesting the AL80 be slug as a pony.

[UCFKnightDiver]

So you think they were suggesting they double up a HP100 with an AL80 or they just simply sling an AL80 and plan it as part of their gas plan?

I was assuming since the OP asked about a pony that the 2nd poster was suggesting the AL80 be slug as a pony.

an 80 is a little big for a "pony" when doing a recreational dive

[H2O 70]

an 80 is a little big for a "pony" when doing a recreational dive

And that is what I thought, hence the reason I was asking him about that.

[emoreira]

Hey, if any of you will throw away an AL80 tank, please reserve one for me. I will be in San Diego next May in hotel .....
Ask for Eduardo Moreira. I will receive one of those dam AL80 tanks with pleasure. :D

[zaberman1]

1. You really need to figure out your SAC rate (which your instructor should go over). Once you figure out the SAC rate, you can multiply it by a conversion factor (to account for depth) and find out how much total cubic feet of gas you will consume on that dive. Assuming you are diving on a single tank, you need to multiply that number by 3 for penetration purposes, maybe more depending on how much reserve you want. For your purposes, the pony should not be used UNLESS it is an emergency, it should ONLY be a reserve calculated independently from what you have on your back. You should have enough in the pony to get you safely to the surface.

2. Doubles are not a bad option at all. For recreational purposes though, if you choose doubles, make sure you are only using 1/6 and not 1/3.

3. Deep dives, especially deep wreck dives, require experience and I commend you for getting the training. Take your time...The deep course you are taking is a recreational one, if you plan on 'staging' or doing deeper penetration, get the technical training.

EDIT: Recreational penetration has many many limitations, gas supply is only one of them...

[adm3745]

2. Doubles are not a bad option at all. For recreational purposes though, if you choose doubles, make sure you are only using 1/6 and not 1/3.


Doesn't that give you the exact useable gas as if you were only diving one cylinder.

[H2O 70]

Doesn't that give you the exact useable gas as if you were only diving one cylinder.

That also sounds like what the NACD or NSS recommends for their basic level of cave cert.

[TSandM]

How did we get into talking about penetration and diving thirds? The OP just said he was going to do some deeper wreck dives -- he didn't say he was doing any penetration. There is generally no need to dive thirds on exterior surveys, unless it is imperative to return to the upline.

As far as a pony bottle size, it isn't dependent on what size tank you use. You're carrying a pony as insurance against a catastrophic gas loss from your primary supply, so the pony bottle needs to have enough gas in it to get you, in a safe and controlled fashion, to the surface from the deepest part of your proposed dive. To calculate this requirement, you need to know what your typical gas consumption rate is, and then make an adjustment for stress (typically doubled). Then you need to look at the ascent profile you would like to do in such a situation.

We use 20 cubic feet per diver as a reserve from 100 feet. If your gas consumption is typically significantly higher than .5 cfm, you might need more.

[zaberman1]

It was certainly my mistake, I misread the deep course and interpreted it as deep and wreck course. Consequently, my post about 1/3 and 1/6 is misplaced. However, the OP should still consider SAC rates, conversion factors, and multiplying by x (how much reserve he wants to maintain in the cylinder).

To answer those that commented on it, yes 1/6 gives you the usable supply in one cylinder and is meant to add an additional barrier to penetration until further training is sought. You would obviously use that number in the above equation instead of thirds to find out total gas supply needed plus reserve.

EDIT: Using 1/6th for a recreational wreck dive penetration on doubles is just as prudent as using 1/6th penetration for cavern and intro. It also gives us the opportunity to do multiple dives ;)

[Web Monkey]

HI,

Planning a few deeper wreck dives this summer.
Would like to have a single tank that can have
superior bottom time over what I have now. using a HP steel
100. I am thinking of the Faber 118 blue steel. Any thoughts..
I am 250 pounds and consume air very fast at depth, but it has gotten
much better in the past year or so. Still would like the safety of extra air.


Sorry to be a wet blanket, but "extra air" doesn't actually provide safety, in fact, by allowing you to extend your dive, it could make your dive more dangerous by allowing you enough bottom time to incur a significant deco obligation if you're not paying attention to depth and time. And while a lot of people will say "Deco is no big deal", what it does is completely invalidate nearly all the emergency procedures you learned in OW class, since surfacing with a deco obligation is not an option (you could be injured or killed).

And in fact, even with a SAC rate of 1.0, your current 100 CuFt tank is already enough to let you rack up a 10 minute deco obligation on a 100' dive if you're using air.

If you're looking for safety, I'd suggest finding a good buddy and working on gas planning.

If you really need more time than you have, I'd suggest doubles and Advanced Nitrox/Deco training as well as the above buddy and gas planning.

Terry

[elan]

When I switched to double tanks I was wondering why the hell I was wasting my time with pony setups. Cumbersome ,heavy and I need to carry 3 tanks for 2 rec dives. Switched to double HP100 and I was able to do 3 rec dives and still have gas, no crap hanging in front of me no rolling under the weight of the pony and hoses are nice and clean routed and redundancy is there. IMHO either dive singles with good buddy and no pony (or very small pony) or just get the doubles in places that requires redundancy like very cold water. YMMV

[DaleC]

use the hp 100, sling an al80


Just curious, but why do you suggest this?


Just call it a stage. Start the dive on the 80, breath it down to 1500psi and then switch to back gas. Now call it a pony and you have aprox. 40cuft. of gas in it. This also allows aprox.140cuft of gas for the dive (100+40). Of course, this presumes one is comfortable doing bottle name switches while under water.

However, unless one is comfortable diving a non conventional system I would personally recommend a single HP130 + good buddy skills or double whatevers and proper training.

[Rhone Man]

Sorry to be a wet blanket, but "extra air" doesn't actually provide safety, in fact, by allowing you to extend your dive, it could make your dive more dangerous by allowing you enough bottom time to incur a significant deco obligation if you're not paying attention to depth and time.

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.

[UCFKnightDiver]

Delete

[izibo]

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

I would go one step further and say it NEVER constitutes a safety problem.

[TSandM]

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!)

[Puffer Fish]

How did we get into talking about penetration and diving thirds? The OP just said he was going to do some deeper wreck dives -- he didn't say he was doing any penetration. There is generally no need to dive thirds on exterior surveys, unless it is imperative to return to the upline.

As far as a pony bottle size, it isn't dependent on what size tank you use. You're carrying a pony as insurance against a catastrophic gas loss from your primary supply, so the pony bottle needs to have enough gas in it to get you, in a safe and controlled fashion, to the surface from the deepest part of your proposed dive. To calculate this requirement, you need to know what your typical gas consumption rate is, and then make an adjustment for stress (typically doubled). Then you need to look at the ascent profile you would like to do in such a situation.

We use 20 cubic feet per diver as a reserve from 100 feet. If your gas consumption is typically significantly higher than .5 cfm, you might need more.

What She said.

[Sas]

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.

[DaleC]

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!)

+2......

[DaleC]

What is "recreational penetration"?

Oh Sas... so many images come to mind.
I guess professional penetration must include some form of monetary compensation???

[Sas]

Oh Sas... so many images come to mind.
I guess professional pentration must include some form of monetary compensation???

:rofl3:

[TSandM]

6ths is a common limit for low-level cave certs. I've never heard it discussed for wreck diving before.

[Sas]

6ths is a common limit for low-level cave certs. I've never heard it discussed for wreck diving before.

Ah ok, in my low level cave cert I have a linear penetration limit + rule of thirds not sixths.

[ianr33]

Sixths applies to cavern and intro cave when diving doubles. Diving a single the limit is 1/3rd.

[Sas]

Sixths applies to cavern and intro cave when diving doubles. Diving a single the limit is 1/3rd.

What agency?

[adm3745]

What agency?

NACD. It's discussed in order to prevent new divers in an overhead from penetrating to far.

Doubles shouldn't even be discussed. The op wants to do rec deep divin (100-130 ft). A large steel tank and a calculated rock bottom will provide plenty of gas. More than enough to reach all NDL.

100 ft: NDL 25 min = ~80 cft
130 ft: NDL 10 min = ~40 cft

A cylinder that will give you at least 120 cft would be suficient for all no deco deep dives. (Those NDL are for Nitrox and I don't have the tables in front of me).

[Sas]

NACD. It's discussed in order to prevent new divers in an overhead from penetrating to far.

Ok then so is there no penetration distance limit? Sorry if this is a bit off topic, just curious about other agencies' qualifications.



Doubles shouldn't even be discussed. The op wants to do rec deep divin (100-130 ft). A large steel tank and a calculated rock bottom will provide plenty of gas. More than enough to reach all NDL.

It's not just about NDL, there is also the redundancy issue when it comes to diving a large single. For me I always had plenty of gas when diving deeper even with a single tank. But I take redundant air below 30m and I take a LOT of gas as more gas can't hurt. I do use redundancy shallower but not always, but deeper than 30m I use twins. Prior to twins I used single + pony and I think if someone does not have any ambition to do go beyond 100-130ft NDL diving, then this is an adequate setup and perhaps more suitable to the OP than twins.

[TSandM]

None of the agencies whose limits I'm familiar with (TDI, NAUI, NACD, NSS-CDS, GUE or UTD) has a penetration limit in distance. The penetration limit is set by gas.

[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.

[TSandM]

Sorry, I misspoke. I wasn't thinking of cavern when I said there were no penetration limits.


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.

.39 is my cold water SAC rate :)

[UCFKnightDiver]

Sorry, I misspoke. I wasn't thinking of cavern when I said there were no penetration limits.



.39 is my cold water SAC rate :)

Besides you Lynne

[Puffer Fish]

Besides you Lynne

I know a bunch, but strap a set of 120 doubles on their back and have them climb a 200 cliff and I would feel better about it... The rest of the time, not so much.

[KY_BOB]

.39 is my cold water SAC rate :)


D@MN, I was proud of mine. I should change my name to Hoover.

[elan]

Besides you Lynne

It is not unusual as one might think, in no current lazy dive with single tank we hit 0.4 very often. :dontknow:

Women get lower rates , I believe my wife has about the same rate and she is a beginner and has not observed the SAC drop yet

[DaleC]

It's not a contest.

[kanonfodr]

It's not a contest.

Yup, nobody gets bonus points for coming back with extra gas. Unfortunately running out of gas is Game Over. That's why I'm so happy about the HP120 I just bought off a guy, for when I feel like yakking the Mahi.

Peace,
Greg

[halocline]

Extra gas with a well trained and disciplined diver does equal more safety, but there are plenty of recreational divers who do not plan their dives well and could use the extra gas to get into situations that could be problematic, either unplanned deco or simply diving too deep to handle a possible emergency.

One cannot say that carrying extra gas will not influence divers' behavior; you can say that about yourself, but not in general. So, I would have to agree that extra gas does not automatically mean extra safety. This is especially true with purely recreational divers, not planning and carefully executing dive plans, who simple want more gas because they go through it too quickly for their own tastes.

[dumpsterDiver]

I generally use larger steel (single) tanks up to 149 cu-ft. It really is kinda ridiculous that the recreational dive industry has often pushed the 80 cu-ft aluminum cylinder as the tank of choice regardless of whether the diver is a 120 lb, 55 yr old lady or a 22 yr old, 240 lb linebacker. Pick the smallest tank that allows you to dive without having a lot of concern about running out of air. Of course if you have to carry the tank long distances on land, this could affect the decision as well.

[Doc Harry]

...I am also looking to carry a pony on a pony bracket attachment...

Why do you want a pony? And why do you want a pony on a bracket? What is your thinking here?

The answer to your question depends quite a bit on your intentions for/with a pony.