twin pacs?

[Sea Otter crew]

Hi All,

I have just started diving again, my last dive 35 years ago. The abstinence was getting too hard to resist.

In the sixties I used (common in Scandinavia those days) a double 7 litre rig (two seven litre tanks). This was because I am fairly small in size and the double 7 felt better on my back than the single 14 litre tank. which I feel very clumsy with. On my retraining to optain an OW certificate, I used the single tanks available at the training centre but still the same old feeling, clumsy.

My questions are:

1. Are there still double pacs like these around?

2. Why do I not see them at the dive sites I visit. Nobody seems to know about them. Are they just out of fashion or?

Some one, please help me with my curiosity.

Safe diving to you all.

 

[DA Aquamaster]

Being unfamilier with that method of designating tank sizes, I am not familiar with the dimensions of a 7 liter tank. But I used to own a couple sets of twin 50 cu ft tanks/ however I separated them when my son started diving and sold them when he out grew them.

One of the problems with my 2015 psi steel 50's is that they were too short to be used with the now standard 11 inch spacing for double bands. The 1800 psi steel 50's tanks are a bit longer and may work with backplates and BC's designed for doubles.

I have always thought a pair of 40 cu ft AL tanks would be a very nice low profile and relatively light option to an aluminum 80 but have never seen bands or a manifold designed for this arrangement. I suspect this would be very similar to what you are describing.

If you are not an air hog you could try a smaller tank like an AL 63, or go with a steel 72 which is shorter and smaller in diameter than an AL 80 with better bouyancy traits.

 

[jonnythan]

I saw somebody using a pair of Al 40's manifolded together. I didn't ask about it, just thought it was kinda neat. I think the main thing is expense. An Al80 is $125, a pair of Al 40's with a manifold and an extra first stage is more like $400.

Maybe you could try out a steel HP80. They're much smaller than Al80's. Of course, You could put together a pair of Al40's or Al45's or something. A pair of Al40's would only weigh 2 or 3 more pounds than an 80, but they're only an inch shorter, so what's the point? A pair of Al45's would weigh almost 10 pounds more and be 8 inches shorter.

I'd say check out http://www.pstscuba.com/aaspo.htm. An HP80 is lighter by 6 pounds than an Al80 and almost 6 inches shorter for 2.6 cf more air capacity and the same diameter.

 

[FIXXERVI6]

The guy that runs athens scuba park
www.athensscubapark.com
has a twins setup, I forget their sizes, total comes to like 65 cu ft or something like that, very neat looking, small and neat, when I first saw it I thought it was some kind of prop to imitate doubles, not real dive gear. I just looks like mini doubles.

 

[Sea Otter crew]

Thanks for replies Guys,

It is not so much for the weight as for the balance and profile. The twinpac is lower in profile than a single big tank, ok wider on the back but with good balance. Well, if I cannot get hold of a pair, I guess I will have to get used to the "bomb" on the back.

Chris.

 

[jonnythan]

Sea Otter crew once bubbled...
Thanks for replies Guys,

It is not so much for the weight as for the balance and profile. The twinpac is lower in profile than a single big tank, ok wider on the back but with good balance. Well, if I cannot get hold of a pair, I guess I will have to get used to the "bomb" on the back.

Chris.

I can't believe I'm saying this, but whichever way you go, check out a backplate with wings as opposed to any modern BC. I'd imagine you used a backplate back in the day (), but I don't know. A bp with a harness is far more stable on the back than a traditional BC. Disappears underwater.

 

[Sea Otter crew]

Jonnythan,

are you a mindreader? I HAVE ordered a BP / wing, it is the Halcoyn type one for me and one for my wife. We are living in Bahrain at the moment and here is a guy at the diving club who assembles those backplates/harnessses.

You are also so right in thinking we had backplates in those days rolleyes: ), that's all we had. BCs were unheard of. When I started again in February this year, I thought "oh my god, what is all this space-age equipment"?

Things have really changed to the better since the sixties. Can you imagine, we were diving in Sweden (my home country) even in the winter with only wetsuits, ok double layers but anyway.

All the best, Chris.

 

[DA Aquamaster]

Sea Otter crew once bubbled...
You are also so right in thinking we had backplates in those days rolleyes: ), that's all we had. BCs were unheard of.

When I started diving I used a back flotation BC by Scubapro as well as a Water Gill At-Pac. I then had to endure the era of the Jacket BC before the backplate and wing arrangement became popular again. Today's backplate and wing is in all reality just an evolutionary improvement on the hard pack and back flotation idea.

 

[rdriver]

Hi Sea Otter,
I have a pair of Faber 46 CuFt tanks with OMS bands and manifold for the very reason that you mentioned compact and well balanced the only thing is they are about as pricey as a banded set of LP 98's but I guess it all depends on the diving that you are going to do..... It seems is though as I am collecting tanks or so my wife say's..... But I do and will always have a set of these in my arsenal of tanks.
Rob

 

[globaldiver]

It is so nice to see another Swede on the board.

Welcome.

Sincerely

Anders