PST E7-120s and E8-130s...

[large_diver]

I think you are a victim of analysis paralysis...;-)

Lay out the factors:

Dimensions: assuming the charter boat tank slot size is not an issue, for a large human like you or me, IMHO the differences in dimensions (2 inches of length less than an inch of diameter) are kind of insignificant.

Dry land weight: again, 5 extra lbs. for a large person is not a big deal. If you are going to be doubling them up, perhaps a diff. story (then again, there are PLENTY of relatively small people out there using double 130s/104s)

Buoyancy -- not much, if any, difference

Cost -- 130's are more expensive

Gas -- 8.3% more with 130s

So it comes down to how you see yourself diving now and in the future. I think you will be happy with either...if you can handle the weight, I say go with the 130s. Besides, chicks dig the bigger tank....;-)

Chris

 

[ScubaDadMiami]

Thank you everyone for your replies...I really appreciate you taking the time to help me with this decision!

In previous articles and posts I have read, it seemed people preferred 130s. Here, however, from what I have seen people seem fairly evenly split in their preference. Hoosier, Large_Diver and,triton94949 you seem very happy with your 130s (although Hoosier you do mention the weight is a concern particularly in terms of any thoughts of future doubling).

ScubaDadMiami and bcsean you speak out strongly in favor of the 120s. Bcsean, as you mention, the valves should wind-up in pretty much the same location for both the 130s and the 120s with the main difference being how far down the base of the tank comes in relation to ones lower back/butt. This would of course be different if the tanks were particularly short (in relation to ones height) and trim necesitated moving the tanks lower down your back (making the valves lower). This would be less than ideal of course bkz then one could not reach back easily to get to the valve.

I guess ultimately I am wondering, what would make the 130 or 120 a better choice over the other assuming both "fit" the diver (neither too long or short in terms of valves and trim previously discussed). Seeing as both are pretty close in weight when empty (only a 1 pound difference when empty (130=-1; 120=0), what makes one a favorite over the other?

130:
shorter (26.12")
wider (8")
10cuft MORE air
5# heavier (43#)

120:
longer by 2.13" (28.25")
Thinner (7.25")
10 cuft LESS air
5# lighter (38#)

BOTH bouyancy = -10.5# full (according to PST chart).

Hmmm...5 ponds does not seem like it would be that much difference in weight (yes?)...but would the fact that it (130) is shorter or wider make it "perform" better or worse than the 120 which of course is slightly longer and "thinner"?
I am still at a loss...

Five pounds may not seem like much. However, when you are already carrying two 40s and other things, and you are near your limit for what you can carry up a ladder, ten more pounds (in the case of doubles), for me, is a lot. More effort swimming through the water means more gas consumed. At 200 plus feet, I want to keep my efforts to a minimum.

If you ever plan on doubling up the tanks and/or engaging in these kinds of activities, you might want to factor this into the equation. Neither is a bad tank. It's more a question of what you need, and what you will need in the future.

Good luck.

 

[Hoosier]

If you decide to go with 120s, you might be interested in this sale.
http://www.scubaboard.com/showthread.php?t=94043

I am still at a loss...

 

[MacLeod]

I think you are a victim of analysis paralysis...;-)

So it comes down to how you see yourself diving now and in the future. I think you will be happy with either...if you can handle the weight, I say go with the 130s. Besides, chicks dig the bigger tank....;-)

Chris

LOL I do seem to be spending way too much time on this...so you say the women like the "bigger tanks" huh, hmmm... yet another variable to consider...

Five pounds may not seem like much. However, when you are already carrying two 40s and other things, and you are near your limit for what you can carry up a ladder, ten more pounds (in the case of doubles), for me, is a lot. More effort swimming through the water means more gas consumed. At 200 plus feet, I want to keep my efforts to a minimum.

If you ever plan on doubling up the tanks and/or engaging in these kinds of activities, you might want to factor this into the equation. Neither is a bad tank. It's more a question of what you need, and what you will need in the future.

Good luck.

No, you are certainly right...every little bit adds up...you make a very good point, thanks.

I HAVE spent way too much time thinking about this, and ultimately find I can talk myelf in both directions.
For example, my current thinking was:

Aluminum 80s (Catalina S80):
Diameter: 7.25
Length: 25.8
Empty Wt: 31.6 ....however, Buoyancy empty=+4.0...so adding +5lbs to make a
a fair comparison to PST empty characteristics= *36.6lbs*

Using the Aluminum 80 as the standard...(weight is empty):
E7-120 is aprox. : 2.5" taller, same width and same weight (1.4 lbs more)
E8-130 is aprox.: same height (.32" taller), .75 inches wider and 6.4 lbs heavier

If doubled: (empty...for Full add: E7-120: 21# , E8-130: 19#, AL80: 11.6#):
AL80= 73.2lbs (84.8# full) (I wouldn't double AL80s...just used for comparison)
E7-120= 76lbs (97 # full)
E8-130= 86lbs (105# full)

(Data taken from most recent PST Spec. sheet)

From this I come away thinking the E8-130 is fairly close in weight to the E7-120 (within 5 lbs empty and 8 lbs doubled (buoyancy swing is 9.5lbs for E8-130 vs 10.5 for E7-120)). For this difference, you have a tank that is the same height as an AL80 and an extra 10 cuft of air(single)(...20cuft double) (albeit in a slightly wider cylinder).

With the E7-120, you have a tank that is 5 lbs lighter as a single and 8lbs as a double, 2.5" taller and 10 cuft less air (single)(...20cuft less as double) but same width as AL80.

Either way, these tanks are going to be heavy...particularly as doubles. However, the weight difference between the 130 and 120 surprisingly does not seem that great.

Does the greater .75" diameter (E8-130) make much of a difference in the water? At 2.5" shorter but .75" wider (130) do you really find thise translates into more energy used....Do you really notice a difference in drag? How do they feel performance wise in the water?

Do you find many dive boats unable to accomodate 8 inch (width) tanks?

Again,thank you *very much* for all of your help...I really appreciate it!!

 

[Dan Gibson]

All joking aside, if you want to carry doubled up 130s (or the old 104s), it really is a good idea to hit the gym. Where you get into trouble with these is not just walking them to the water, it is when something goes wrong like a slip or trip. The extra strength you get from working out will help protect you in these cases.

I once witnessed Jason Weisacosky (OCDA) slip and damn near fall after hitting a slick step at Blue Grotto and survive it. He is a pretty good size guy. I'm guessing he hits the weight pretty hard. I really thought he blew out his knee when it happened. He just stood up and walked away like nothing happened. That would have hurt most people. I also know a guy who broke his ankle when he triped while carrying these tanks.

As long as you can handle the tank weight, it isn’t an issue. I am not a big person compared to you, but I also have E-130. I think that twin E-130s is going to hurt me, but other member was teasing me to exercise for that.

 

[Hoosier]

See, that was him who was teasing me. :11ztongue

He is absolutely right.
I didn’t mean “just carry the double,” but “proper handle the weight” like he said.

Thanks to my military training, I can carry even the double 149s, but it doesn’t mean that I can handle those weights properly. I am working out at the gym more again, even today….

All joking aside, if you want to carry doubled up 130s (or the old 104s), it really is a good idea to hit the gym. Where you get into trouble with these is not just walking them to the water, it is when something goes wrong like a slip or trip. The extra strength you get from working out will help protect you in these cases.

I once witnessed Jason Weisacosky (OCDA) slip and damn near fall after hitting a slick step at Blue Grotto and survive it. He is a pretty good size guy. I'm guessing he hits the weight pretty hard. I really thought he blew out his knee when it happened. He just stood up and walked away like nothing happened. That would have hurt most people. I also know a guy who broke his ankle when he triped while carrying these tanks.