Which tank sizes are commonly used for doubles?

[imasinker]

Hi everyone, Hope you all are having a great dive season.

I am sure it has been asked and I would like to know what most of you use for doubles and in tank size. I am making the move to doubles this winter. I have a faber 130 and was thinking should I double it or down size to smaller tanks. I have seen some use these and weigh doesn't seem to be an isue. I am 6'2 and using a OMS set up with S/S BP and harness. What are the sizes most commonly used or favored? Opinions and pointers are most appreciated.

Thanks

Rob

 

[ucfdiver]

I use LP108's, which are the same size as your 130's, and the only other size tanks I'd look at are Faber LP85's (I think there's a HP100 equivalent to this tank, too) due to their light weight.

 

[nereas]

I have one set of PST E8 twin 130s which I mostly use as portable banks to charge up my smaller twin 72s between beach dives with the latter. And for doing this I use a trans-fill hose like that described by Gary Gentile in his tech book(s).

The nicest thing about the twin 130s is that they will go to the extreme of O/C scuba, which is 350 ft. So anytime I get a call by my crazier techdiving friends, who want to go really deep to see a wreck, the twin 130s are always available and waiting to be filled.

The not so nice thing is that they are completely out of the question for any beach diving. So these are strictly for boat diving, period.

So I think you should keep yours, and simply get in addition a nice smaller set of twins, like LP 80s or 72s, as well. Together with a trans-fill hose.

Then you will be a happy man.

[Herodotus, the Greek historian, and inventor of history as a science, defines "a happy man" in the first chapters of his book, in his narrative on King Croesus (KROISOS in Greek).]

 

[jamiep3]

Just my opinion, but I'm looking at PST or Worthington twin 100 HP. They are only about 4 pounds heavier that my twin AL80's and give you about 40 Cu/Ft more. Seems like a fair trade, particularly since getting true 3442 fills is pretty easy these days.

 

[Rogue_Diver]

Something to consider: you can do two full technical dives (not every dive conceivable of course) with double 130's, but you will not be able to do this with a set of 100's. The 100's will hold plenty of gas, but will not have suitable reserves for dive two. If re-fills of the gas your planning to use are not available on the boats you dive on this may limit you. The flip side has already been mentioned and that is the weight of the larger tanks. You can beach dive, but it will be challenging.

 

[S. starfish]

It really depends on the diving your doing. I know a fair number of people who started out with hp130's and later switched to 100's because of weight issues. Around here of course, we're doing mostly shore entry and one deco dive a day, so 100's are fairly ideal for that. The only time they really present a problem is when you end up in an area where you want to do two dives but can't because of gas limitations.

If you're going to be doing mostly boat diving I'd go with the 130's. They really are a pain to lug around, but if all you have to do is cart them to the boat and then roll off the boat, then its not such an issue and you might as well have as much gas as possible.

 

[Divin'Papaw]

If you're going to be doing mostly boat diving I'd go with the 130's. They really are a pain to lug around, but if all you have to do is cart them to the boat and then roll off the boat, then its not such an issue and you might as well have as much gas as possible.

But you still have to get them back into the boat. That's the hard part.

Being on the small side (5'8", 155 lbs or so), I went with HP100s.

 

[willardj]

I have a set of 95's(119's) and love them. There shorter and lighter than 104's(130's) and they trim out great. I also have a set of 72's which are super small and lite. Great for shallow boat dives.

As far as most common. Down in cave land LP 85-LP95-Lp104 are the most common.

 

[rjack321]

It really depends on the diving your doing. I know a fair number of people who started out with hp130's and later switched to 100's because of weight issues. Around here of course, we're doing mostly shore entry and one deco dive a day, so 100's are fairly ideal for that. The only time they really present a problem is when you end up in an area where you want to do two dives but can't because of gas limitations.

We often end up using a bottom stage for either dive1 or dive2.

dive1: hp100s+al80 of bottom gas+1x al40 of deco gas
dive2: hp100s as reserve and an al80 of nitrox for a recreational dive
other dive2: hp100s and an al40 of deco gas

You can do alot of midrange deco dives off one set of hp100s/lp85s just continually swaping out bottom stages (with decent consumption and suitable training).

The 130s are ugly to get back aboard the boats I'm diving off (Ribs mostly). So like you we use 100s and just split up the gas into extra cylinders if we need to.

 

[imasinker]

Thanks all, My I didn't make clear the types of dives I do. I logged over 64 dives this far this year. 30 have been boat dives being a few two tank but usually a three tank dive. My average dives would be 80 feet to 100. I like the idea extra gas and not having to unload and load up a new tank after each dive. I also like to increase my bottom time on some dives. I like the suggestion on carrying a bottle for bottom gas, but was thinking about using a deco bottle for safety stop, thus decreasing the usage of gas from the doubles? What the opinion on that. Maybe this is a unusual thing to do, but I think of it as practice and readying myself for further tech courses i am going to be taking or am I way off and jumping the gun a little?