Finally think i've decided on steel.....

[jonnythan]

Come on, you need the E8-119. It's an LP 95 pumped up to 3442 psi. Plenty of air.

 

[jhelmuth]

In reply to the two previous posts, im 6'0" about 160lbs (dont use much air), and will be diving wet. Right now, im planning on doing some mid-level wrecks, which can be found in lake michigan/huron in around 50-90ft of water. The possibility of deeper dives does exist for later on, which is why i initially wanted a 100CF tank (rated at LP), or a steel that could handle a 3000 psi fill which would give over 85 CF.

OK - @ 90 ft you're going to be limited to 25-30 mins BT (NAUI-Navy tables). That range is probably OK for a single cylinder (NO PENETRATION!). For deeper wreck dives I think you ought to begin considering advanced training in deco and using either doubles or deco bottle slung on the side. If you are fixed at keeping within NDL - then you'll just have to accept shorter BTs. If you want to go doubles (eventually), then IMHO AL cylinders are the way to go (use 2 neutral 80s or smaller) - but that is NOT based on experience (I don't dive doubles - YET).
As far as size - what is your air consumption like? Do you need more than 78-80 cuft of gas? I'm all for having a reserve amount of gas, but I'm not a fan of larger-than-necessary cylinders.

Oh yeah... you didn't say anything about water temps. I assume the water up there is quite cold. So will you be diving "dry"?

 

[Xanthro]

You decided to buy a steel tank right when finding steel tanks is very hard. They are sold out almost everywhere.

Good luck finding one. I hope you find one.

Xanthro

 

[jhelmuth]

Also...

Note that the higher pressure tanks may increase the likelyhood of a "frozen" 1st stage (depending on ambient water temps and the limits of the 1st stage design) and is harder on it than the lower pressure cylinders.

 

[kawboy579]

Also...

Note that the higher pressure tanks may increase the likelyhood of a "frozen" 1st stage (depending on ambient water temps and the limits of the 1st stage design) and is harder on it than the lower pressure cylinders.

I never really considered water temperature in the equation. I would really like to have a shorter/wider 100CF or more tank because i have a sneaky suspicion that i will want to venture into some deco dives as i gain more experience. I have not come across any neutrally buoyant aluminum tanks? Are they weighted or have a greater wall thickness?

 

[Quarrior]

Also...

Note that the higher pressure tanks may increase the likelyhood of a "frozen" 1st stage (depending on ambient water temps and the limits of the 1st stage design) and is harder on it than the lower pressure cylinders.

I would really like to understand your statement about a HP tank having a tendancy to create freezing in a reg first stage easier.

It seems to me if one is diving in cold water, they should be using a cold water reg like a Zeagle DSIV or DSV or an Apeks or the like. If one is using a reg designed for the diving they are doing, how could tank pressure alone cause a problem?

I believe a reg that is not designed for cold water will tend to freeze regardless of tank pressure.

As for pressure, please keep in mind you're generally talking about the difference between 3000 psi and 3442 psi. Unless of course you are using the 2500 psi LP tanks as your benchmark for your pressure determinations. Either way, a quality reg will eliminate the problems of freezing.


From the stand point of it being harder on the reg, again, if the reg is a good quality unit, how is HP hard on it?

Thanks

 

[So Cal Divin]

E7-100 or LP95.
The big question that hasn't been asked yet is what do your buddies dive ? And what is your consumption like compared to theirs ?
I did a long walk rocky entry beach dive with my buddies E8-119 water heater. My buddy was diving a LP95. He surfaced with 700 psi. and I had 1350 psi. to walk back to my truck with. Never again. Shallow beach/reef diving AL80. Boat or deep diving E7-100 OR LP95. I don't care for a 8" tank it feels like a beer keg on my back. I'm 6'1" so tallers better than fatter for me.
Your diving a wetsuit so plan on being cold and using more air will 80 cu. ft. be enough or will you be the determening factor on when the dive ends or will NDL be the factor.
Hope this helps and tell them to make some more PST E7-100's for x-mas!

Sea ya. Jeff

 

[OE2X]

I went with the PST 119's and 130's and here is why:

Gas, gas and more gas. I have no problem with finishing a shallow 45 or 50 minute with 2000 psi left. Guess that means I can use the same tank on my next similar dive.

For my 130's they will always be for single tank dives. I generally have plenty of left over gas when I surface. Should my buddy go OOA well we will both be glad that I have that tank. No pony bottles for me...

In the future:
The 119's can be doubled up. Albeit they are heavy, but you have a lot more back gas than the 100's.

Good luck finding them, but they are worth the wait.

 

[TX101]

I've never understood the American thinking of "It's higher pressure so it is subject to higher stress and wont last as long".

Over here, our "Low Pressure" tanks are 232 bar or 3400 psi. EVERYBODY has their tanks filled to at least this pressure. Our "high pressure" tanks are 300 bar or 4400 psi. Some people prefer these HP steels - but they are *very* heavy on the surface and it's difficult to get good fills. Also, van der walls comes into play at this pressure and you only effectively get 270bar even with a 300bar fill.

At no time have I read ANYTHING that my regs will fail sooner because It's being subjected to 232bar (3400psi - or "HP" in the US). All regs are designed to handle high pressure (300bar) anyway. Also, most people dive steel since Aluminium is nearly double the price (becuase it's usually imported from the US, where Faber makes steel cylinders here and exports them to the US I believe)

 

[jhelmuth]

I would really like to understand your statement about a HP tank having a tendancy to create freezing in a reg first stage easier.

It seems to me if one is diving in cold water, they should be using a cold water reg like a Zeagle DSIV or DSV or an Apeks or the like. If one is using a reg designed for the diving they are doing, how could tank pressure alone cause a problem?

I believe a reg that is not designed for cold water will tend to freeze regardless of tank pressure.

As for pressure, please keep in mind you're generally talking about the difference between 3000 psi and 3442 psi. Unless of course you are using the 2500 psi LP tanks as your benchmark for your pressure determinations. Either way, a quality reg will eliminate the problems of freezing.


From the stand point of it being harder on the reg, again, if the reg is a good quality unit, how is HP hard on it?

Thanks

So, you're probably aware that when a gas is compressed, the temp. of a tank is heated because of the condensing of the molecules. The reverse is true as gas is "uncompressed" - it gets cold (sometimes extreemly cold) as it expands. THis is basic physics. So the higher the pressure differential, the more this happens (this is how your A/C works).
I do agree that you want a cold water reg. What does he have/dive?
So here is an example. Most people will probably agree that Scubapro 1sts are not cold-water regs. But there are plenty of cases that will show you that when a scubapro 1st is combined with a LP steel tank, freezing is never a problem. It only shows up when the tank pressure is ~3000+ PSI.
Higher pressures are harder on the lubrication and parts in general. If you use HP tanks, your maintenance cycle for your regs (1st stages) should be more frequent (assuming you are an active diver). While I'm not one of them, some divers will swear that you are required to use a HP DIN connection if using tanks beyond 3000 PSI (IE - can't use a std. yoke).