PST 130 / 120 Agony!!

[BB7]

I have been going crazy trying to decide between 2 of Pressed Steel's tanks...the E8-130 and the E7-120 (the old LP104 and HP120). I would really appreciate your help!!

I am 6'3" and looking to use them as singles to start and doubles in the future.

While I generally dive dry, I would like to be able to use them with a 3mm drysuit (singles) on rare occasions. My diving tends to be pretty equally spread out between fresh and salt water....my passion is wreck diving when I can.

Are the 130s too heavy to swim up full as singles in a 3mm?

Any experience with trim differences between the two?

Do the 130s "feel" much heavier than the 120s when climbing into boats are walking short distances for shore dives?

Why would one prefer the 130s over the 120s other than the 130's additional weight (thus less lead on weight belt).

Thank you...I greatly appreciate any and all help!!

 

[Uncle Pug]

I don't know about swimming a single 130 up wearing a 3mil... if it ever gets warm enough here for me to wear a 3 mil I'll give it a try with a loaded 104 and let you know.

As for trim I don't think you will notice a difference.

As for it being too heavy for you to climb up the boat ladder or waddle down the beach to the water... well... that depends on your physical condition I suppose.

I know that hiking in my double 104s with a slung 40cf deco bottle gets to be a real chore if it is much over 1/4 mile and I hate having to do it on unimproved trails.

The boat ladder is a piece o cake.

Oh... for what it's worth... I can't swim up a twinset of loaded 104s.

 

[scubafanatic]

...well BB7, I got an E8-130 about 3 months ago....have dove it maybe 3-4 times...and just ordered an E7-120 today, maybe get that in a week or so.

I dove it in fresh water in a full 7 mm wetsuit......per PST the E7-120 is 36 lbs empty...the E8-130 is 42 lbs empty.

The E8-130 was managable weight-wise on land, but I've not done any boat dives with it......I am planning boat dives with the E7-120, I've special ordered it for a boat dive trip in Oct...no experience with the E7-120 on a boat yet, or on land either........however, since I use Faber LP 120 steels, almost anything will seem lighter to me than those tanks.

The E7-120 is 2 " longer and 3/4" narrower than the E8-130...which might make a difference since you're about 1/2' taller than me.

Anywhere where weight will be a real issue I dive my 'petite' LP 85's.......slightly smaller/lighter than an AL80 with more gas capacity.


Karl

 

[BB7]

Thank you Uncle Pug!

Uncle Pug, now that both have the same service pressure, why would one choose the E8-130s over the E7-120s?

Which set would you recommend?

Thank you for your help!

 

[SeaJay]

I've found that if I dive wet and I use steel tanks, it puts *all* of my weight behind me. In short, my center of gravity moves back, but my center of buoyancy hasn't changed. The net result is that I find myself easily "turtled."

More on this at http://www.bftwave.net/lcscuba/homebc.html

This can be changed by placing weights further forward on my body, but doing that usually means that I'm overweighted... And swimming with too much air in my wing... Causing lots of drag and overall buoyancy issues.

...So I leave the weight on the dock... Which puts me back in the same situation... Now I'm properly weighted, but it's too far back and I find that my rig has a tendency to flip me over on my back if I swim in any position other than totally horizontal. Approaching a wall or squeezing through a doorway of a wreck on it's side, for example, might require a position other than horizontal... And my rig wants to take me on over. I have to scull with my hands - not a good thing, since they're usually busy with a line or lights or whatever - in order to not lose my balance.

Thus, I always dive AL80's when wet. Their buoyancy characteristic of "passing through neutral" as they empty - the same reason why they make good stages - keeps me balanced and trimmed better.

With drysuits, I understand that the whole steel tank thing is a better idea than aluminum tanks, since the buoyancy characteristics of drysuits is different/controllable... And the buoyancy characteristics of a steel tank helps to remove some of the weight that you'd otherwise have on your hips.

That said, the above situation is only my personal experience... There are others here who dive steel with a wetsuit and don't have the trim issue that I do. Their body/trim/buoyancy is just different than mine.

My point is that you might not find that one tank is going to be optimal for both wet diving and dry diving.

Because of my trim issue, if I were purchasing ONE tank to dive both dry and wet, I'd do it either in an AL80 and deal with the consequences (reweight) of using the drysuit, or I'd consider a steel tank who's buoyancy characteristics aren't so extreme. (e.g. close to neutral or even slightly buoyant when empty.)

For a list of tank buoyancies, to help you in your decision, check out http://www.diverlink.com/gear/tankspecifications.htm

 

[BB7]

Thank you Karl!

Karl, in terms of trim and overall impressions, how did you find the 130?

Why did you decide to now get 120s...were you not happy with your 130s?

Which size would you recommend and why?

Thank you!

 

[BB7]

Thank you SeaJay!

Yes, regarding the "turtle effect" you discussed...I DO know what you mean. I have experienced similar problems myself when diving with large steels (particularly wet)...it can be a bit frustrating, particularly as you mentioned when diving wrecks or any other situations that require a position other than horizontal.

Perhaps this point would make the 120s slightly more preferable(?) as their buoyancy is slightly less negative than the 130s. (120: -1.3(Empty) -10.3(Full) , 130: -4.8(E) -14.6(F)).

Thanks again SeaJay!

 

[Uncle Pug]

BB7 once bubbled...
why would one choose the E8-130s over the E7-120s?

Which set would you recommend?

1. personally if I am going to carry that size tank it is because I want/need the extra gas... 130 is more than 120.

2. you say set... that implies doubles... same answer as 1.

If I want to do dives where I don't need that much gas then a smaller tank would do... say a nice little steel 72.

However... I really like my small twinset of steel 72s. They were cheap to put together and I can do at least two (and sometimes three) recreational type dives with a single 2500 psi fill. They don't weight that much either.

So... my advice: The answer is always more tanks and there is no sense in having 120s and 130s (IMO).... better a couple of 130s and a couple of 72s.

 

[sasdasdaf]

agreed, get the E130s if you need the gas. then you can get a set of AL 80s for wetsuit diving and you're done.

i have a set of E130s here in the northeast. i would have bought E119s (the old 95s) but they tend to turn me on my head.

 

[scubafanatic]

...well BB7, I really like the E8-130...a good length for me, a tolerable weight, good gas capacity, fine balance, slightly negative empty......I'm thinking of buying another one to use as a single too.

I bought the E7-120 for a special application.......some dive boats are only equipped to handle standard 7.25" diameter tanks, since that's the diameter of the common AL80...my goal was to find the largest capacity tank possible with the limiting parameter being a diameter no larger than 7.25"...that's why I bought the E7-120...otherwise I'd prefer the E8-130.

I'm something of an air hog, and feel constrained by an AL80......the E-series are 3442 psi HP tanks, so even if I only get a 3000 psi boat fill with my E7-120, that still gives me 105 cu. ft....which is 36% more air than an AL80.

I don't think there will turn out to be a big difference between the E7-120 and the E8-130...but that will have to wait a week or so until my E7-120 arrives to be sure.

Of course there's also the E8-119 to consider......which is only 24" long.......there will be shorter divers who will probably favor this tank.

The E7-120 is 6 lbs lighter empty, which will be nice...but the E8-130 is 2 " shorter.......but the favored length depends on the diver's body type/length, only you can judge the 'best' length.

Karl