Steel tank question

[EIGHTWGT]

I am having a real hard choice trying to decide between a hp 100 CF or 95 LP steel tank.

I will use it both cavern / cave diving and offshore diving.....

Id like to hear both sides of the coin here...... I have been diving with a 100 HP (E7 pressed steel)

 

[Mark Vlahos]

I am having a real hard choice trying to decide between a hp 100 CF or 95 LP steel tank.

I will use it both cavern / cave diving and offshore diving.....

Id like to hear both sides of the coin here...... I have been diving with a 100 HP (E7 pressed steel)

To answer your question I need to get out the crystal ball and peer into the future.

For future use in a cave you will need doubles, if this tank is to be part of a doubles set then you need to consider that. The LP 95 is 95 cubic feet at 2640 PSI, some shops in cave country are willing to fill double low pressure tanks up to 3500 PSI. Now I don't want to pass judgement on overfilling, but I will say that if I want 252 cubic of gas I would rather have a set of doubles that is designed to be filled to that pressure. An E8-130 set will get you 260 cubic feet at 3442 PSI and E7-120's will get you 240 cubic feet.

Here are some numbers of various tanks for comparison

Double LP 95's at 2640 PSI = 190 cubic feet
Double LP 95's at 3442 PSI = 248 cubic feet
Double LP 95's at 3500 PSI = 252 cubic feet
Double HP 100's at 3442 PSI = 200 cubic feet
Double HP 100's at 3500 PSI = 203 cubic feet
Double HP 120's at 3442 PSI = 240 cubic feet
Double HP 120's at 3500 PSI = 244 cubic feet
Double HP 130's at 3442 PSI = 260 cubic feet
Double HP 130's at 3500 PSI = 264 cubic feet

If you want to buy one tank now and double it later the E8-130 is quite common in cave country. That tank is fairly large, if you are not a large person then the tanks you are considering make sense. If you are large then save your money on the smaller tanks and get the larger ones.

A cave dive is governed (among other things) by the smallest tanks on the team, so if you have small tanks and your buddy has huge tanks then you will turn the dive based on each diver using 1/3 of YOUR gas supply, all other gas is held in reserve for the exit and emergencies.

If you are not intending to buy this tank for later use as doubles then the LP95 is physically larger than the 100. The 95 will be able to be filled almost anywhere and you may get some short fills with the High Pressure 100. In either case they will most likely have plenty of gas for normal recreational dives.

I hope this helps.

Mark Vlahos

 

[pdoege]

I have LP95s and I've dove HP100s.

The 100s are about the same size as the LP85s. They are really nice tanks. Because of their smaller profile you can go about as far as the larger 95s.

Given the choice I'd go for the 100s.

If you wanted bigger tanks I would skip the 95s and go to the 130s.

Peter

 

[DivesWithTurtles]

Here's an interesting discussion on the issue.

 

[bob1dp]

I’m tire of diving with my steel tank. I go really slow and I keep getting stuck on the reef.

 

[O-4]

:lol3:

 

[Doc Intrepid]

I’m tire of diving with my steel tank. I go really slow and I keep getting stuck on the reef.

LOL...you're killin' me here!

 

[Doc Intrepid]

I am having a real hard choice trying to decide between a hp 100 CF or 95 LP steel tank.

I will use it both cavern / cave diving and offshore diving.....

Id like to hear both sides of the coin here...... I have been diving with a 100 HP (E7 pressed steel)

dude, get another of what you currently own.

The PST E7 and E8 series are great tanks - some would say the best you could buy.

By getting another of the same tank you not only make doubling them up easier in the future (and a set of E7-100s is a sweet set of tanks, too), but you make gas planning easier for your dive plan: The math for the first tank is going to be the same for the second - consumption rates, rock bottom, thirds, etc. Owning two different tanks means two sets of calcs each time.

Keep it simple.

FWIW. YMMV.

 

[rgbmatt]

Also remember that LP95s only hold that much when overfilled. If you lose the
+ hydro rating, it effectively becomes an LP86. Not much difference between that and a (much cheaper) 80.

 

[lamont]

I am having a real hard choice trying to decide between a hp 100 CF or 95 LP steel tank.

I will use it both cavern / cave diving and offshore diving.....

Id like to hear both sides of the coin here...... I have been diving with a 100 HP (E7 pressed steel)

another E7-100 would make a nice set of small doubles. some people prefer double (overfilled) LP80s to double E7-100s for balance though -- you may have to get an Al backplate and put a little weight around your waist with the E7s.

instead of the LP95, i'd look at an E8-119 which is the same tank basically, only rated for 3500 psi. they double up okay, except for the same caveat that the balance is a little towards the head. and once you start looking at tanks that big, you might as well buy a pair of E8-130s (which balance a little lower than the 119s).

if you are diving in cave country you may be able to get routine overfills on the LP tanks to 3500 psi, which makes the PST E-series less attractive -- otherwise, the E tanks seem like a no-brainer.