Dbl 72's or hp 80's?

[Jim Lapenta]

Am nearly finished with DM and I've decided to postpone my route to full instructor for various reasons. One of those is to gain more experience as a diver. And while I will continue to work with my lds as a DM and possibly AI I've decided to get some tech training and add a BPW to my gear collection as well as doubles. I've pretty much decided on a DSS rig w/pro fit harness. My question is should I double up lp72's or hp 80's. I'm 5'7" around 160 but slim build. I was thinking the 72 for a narrower profile due to my build and feel the longer tank may be better trim wise. I love the hp80's and like their buoyancy characteristics. Cost is not an issue since I have both tanks. I've got 4 72's and 2 of the 80's. I'll get the 72's o2 cleaned should I decide to go for them. They are yoke however and so I'll need to change the valves. Plans are for oceanic cdx5 first stages, delta 3 second on primary and alpha7 or 8 on octo. My stage/decos will be al40's with alpha 7 secondaries and px2 first stages. Also have no problem getting the 72's pumped to 3000-3200. My air consumption is very good and I have no problem doing a 54 minute multilevel dive with a max depth of 125 ft for 8 minutes 70 for 10, 10 at 50 and the remainder from 25-15 including stop and using around 2400 psi out of one of those 72's. I've really not calculated my exact rate but will be doing so next week. Any thoughts?

 

[Diesel298]

i did the double 72's for my first duobles. and quicley realized they where not sufficent for me.
if moneys is not the issue get some 100' 104's something like that

 

[dumpsterDiver]

I gave up double 72's when the LP 125's came out. With a decent fill the single big tank has more air and is much easier to dive with and cheaper to maintain.

 

[Diesel298]

I gave up double 72's when the LP 125's came out. With a decent fill the single big tank has more air and is much easier to dive with and cheaper to maintain.

my thoughts exactally
i have lp 125 and lp 98's now

 

[OneBrightGator]

Are the 72s and 80s the same size? I'm not real familiar with HP80s, but if you have new ones (i.e. E7-80s) then they will use the same manifold and bands as the 72s, so you could really try both if you wanted to. Keep in mind that if you have old HP tanks, they have a different thread (which no longer is in production, as far as I know) so a manifold might be hard to find, in the future parts may be hard to find, that should weigh in on the decision if it's the case.

I'm 6' 3", so I usually opt for longer tanks, so if you had to pick one I would say the 72s.

Also, if your 72s are old, be careful overfilling them, they aren't quite the same as the LP series tanks.

 

[Jay Roy]

I think your going to find that those small tanks arent going to cut it.....When doing tech dives you have to remember that you gotta have enough gas to bail out a team member if something goes wrong...When I started my deco course, I had a set of LP 80's and I found on the 2nd dive of the day, there just wasnt enough gas to complete the dive...Right now i have a set of LP PST 104's and a set of PST LP 80's.. I havent dove the 80's since last May when my club went to Gilboa..I'm looking to sell them and get a 2nd set of 104's..

 

[karstdvr]

. Also have no problem getting the 72's pumped to 3000-3200.

Ouch-that is kind of high for 72s,I hope they are the medium pressure 72s.

Backmounting 72s is great,they are a wonderful tank to use,but are limited in the amount of gas you'll have available. If you are using them for some no deco or minimal deco diving,then they could be a good choice.

 

[boydski]

My question is should I double up lp72's or hp 80's. I'm 5'7" around 160 but slim build. Any thoughts?

Hi Jim,

I'm the same size as you and dive a set of double lp 72's for recreational depths. They are great, trim out very nicely and are easy to manage. As mentioned above, when diving deeper, especially when doing two trimix dives, you'll want a bit more gas. I often dive a set of HP 100's, which trim out the same as the 72's, but hold a lot more gas.

I don't think you'll like the trim with the twin HP 80's, as they are very short tanks, and if you set them in the bands so that you can reach your valves, I think you'll find you'll be trimmed head down with all that weight so high. For guys our size, I think you'll find the lp 72's, lp 80's and hp 100's are the most comfortable sizes. The lp 95's/hp 119's work too, but they are very heavy.

Since you have so many 72's already, I'd look at doubling up a set of them, but keep in mind you'll probably wind up with a set of larger tanks down the road.

Good Luck!

 

[Jim Lapenta]

Thanks everybody! Lots to think about here. Also realize that I may want to go bigger down the road and fully expect to. Just thought getting started would be easier to use what I have and work up. Thanks