Question Twins or Sidemount or 18L?

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swimmingpooldivein

Contributor
Messages
71
Reaction score
103
Location
Australia
# of dives
500 - 999
Hello!

Firstly, context about me: I'm a PADI Rescue diver, 500 lifetime dives, 100 dives this year so far. I mostly do shore diving and, on rare occasions, do boat dives. I own a Tusa X-Wing BCD (size medium) (owners manual). It's a rear inflate jacket. And I own 2 Faber steel 12.2L tanks. I'm also an SDI Solo Diver, I own a Faber steel 3L bailout tank, and I do solo shore dives every so often. I have no interest in tech diving or cave diving.

The problem: Compared to most of my dive buddies, I'm typically finishing dives with 25% to 40% more air than them; meaning, I have a lot of gas remaining. But one group of my dive buddies have recently decided to switch over to twins and sidemount (typically 2 10L tanks), which means I cannot keep up with their dive times anymore. I'm trying to find a solution that allows me to easily dive with (1) the single tank buddies and (2) the two tank buddies while (3) retaining the ability to solo dive easily. I believe I have 3 options available:

Option #1: Twins. Solve my problem by copying my friends. For my BCD, page 21 of the BCD manual says it can be configured for twin tanks (doesn't say how - install a backplate?); otherwise, I need to buy a new BCD. And I buy a manifold. One downside is I heard that once I attach a manifold to my 2 12.2L tanks, it's extremely difficult / annoying to revert. Meaning, to dive with a single tank, I'll need to buy a 3rd tank, as well as own 2 BCDs. And then money to pay for the twins learning course at my local dive shop.

Option #2: Sidemount. Solve my problem by copying my friends again. I'll need a new BCD for sidemounts. The benefit is I can still use my existing tanks for both sidemount diving as well as single tank diving. Another benefit is I can simplify the physical exertion of walking from the carpark to the shore entry/exit (some dive sites have many stairs) by going 1 tank at a time, but even then, carrying a single 12.2L tank by hand over a long distance is very difficult for me. Alternatively, I can walk to the entry/exit point with both tanks attached to my body, but I've heard that is way more awful than carrying twins. And then money to pay for the sidemount learning course at my local dive shop.

Option #3: Single 18L. A single 18L will provide plenty of air for me, even if my buddies are diving with 24L. However, my BCD's manual says max tank capacity is 15L. I'm assuming one risk is a single tank band isn't enough to confirm the tank won't slip and fall out while walking. Page 21 of the BCD manual does say the single tank adapter can be replaced, so I could instead buy a single tank adapter with 2 tank bands (example). Then I buy a Faber steel 18L tank. I thought a second risk is the BCD can't provide enough lift, but given the tank's buoyancy (-0.75kg empty; -5.75kg full), and my BCD provides 13.3kgf of lift capacity, this shouldn't be a problem. I don't need to buy a new BCD, and I don't need to pay for a learning course. Any other risks I'm missing?

My preference is "Option 3: Single 18L" because it requires less gear while still supporting all the different kinds of diving I do. And it's not a horrible option for getting all the gear from the carpark to the entry/exit point. However, I don't believe Option 3 is standard; most people seem to solve this problem with twins or sidemount. So given the context about me and my diving, I'd love to hear the community's feedback. Please and thank you!!!
 
Why not your regular set up and slinging an extra bottle (sidemount style). Basically a combination of back mount and side mount.
Sounds easiest for me if yout bcd has two d rings (hip and shoulder).

And you only bring the extra bottle when you need it.
 
The 18L tank is a big, heavy, unwieldy thing. I'd advice against it. Slinging an AL80 (because you'd want something neutral, not another steel tank) for extra gas works and makes sense, as does doubles (but probably not with your current BCD). Consider the protocols for using it (breathe it first; keep adequate reserve on your back for sharing with your buddy), but otherwise it's not particularly complicated.
 
Ditto the two posts above. Use your current rig, but carry a slung AL80 with its own reg. Breath alternately from your back tank and your slung tank so you always have gas in one of them, sidemount style. Great redundancy, chap solution. The 18L tank sounds awful.
 
If you have the cash to spend, i'd go with twins and a new bcd. Sell one of the 12 l and the 3 l to recoup some of the cost. That way you still have the option for easy single tank dives. Twins are a much better option if you like solo diving. Twin steel 10's are easier to handle the 12's and give you loads of air. No way would I buy an 18L tank. I'd say you're experienced enough to teach yourself to dive recreationaly with a twinset. There is really nothing complicated about it.
 

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