Going to twins, best way?

[Dredgy]

Off balance, really screw up your trim and weighting. Plus on the boat you wouldn’t be able to sit properly with tanks supported by the rack/bench.

This is fascinating to me, because with the first part I find it to be the complete opposite. I was always having to work to maintain trim until I got this tank which I just bought because it was on special. On the boat I've not noticed it to be much of an issue but I usually gear up in the water. I will try next time on the boat to see what it's like. Thanks so much for that, I find it super interesting. Maybe I'm doing something spectacularly wrong!

 

[NothingClever]

Now I think people are reading a bit too much into my original post - the bit about strength was meant to be levity/self deprecation. I'm a perfectly fit person, I just look a little stronger than I actually am. I have slight tremors in my hands which gives me dexterity issues - but again they're a minor issue for everything except tying knots which is hugely troublesome for me. I don't expect any issues with shutdown drills (though I've been wrong before).

Dredgy, I definitely didn't get that from your first post. You said you had trouble with dexterity, tightening straps and tying knots, that you're quite weak and you're not sure you could lift a twinset. Those things don't make me think, "Right, here's a cat who's ready to strap on a twinset."

If you just want to know what second tank to buy, you can review the comparison tables at DGX to make an informed decision.

 

[Dredgy]

Dredgy, I definitely dfidn't get that from your first post. You said you had trouble with dexterity, tightening straps and tying knots, that you're quite weak you're not sure you could lift a twinset. Those things don't make me think, "Right, here's a cat who's ready to strap on a twinset."

If you just want to know what second tank to buy, you can review the comparison tables at DGX to make an informed decision.

Yes you’re right, I overexaggerated a fair bit and I’m sorry, I just though it would make for a more interesting read. I swear it comes across more sarcastic in real life! But the gist was a twinset will solve the most minor inconveniences in my life, and I’m sure it will create a lot more and I will spend countless thousands of dollars and years of my life trying to perfect those new problems But I need that, if I don’t have a problem to solve, no matter how small, then I have no motivation. Like the only reason I learnt how to scuba dive was to solve a problem And it’s become one endless loop

If I ever get to cave diving then dexterity will be a severe issue with tying off lines, but I’m a looong way from even considering that.

On the plus side, I discovered beach carts and learnt a lot about tank position from Marie which is a lot more than I wanted from this thread!

 

[lexvil]

While I love buying stuff I don’t need and if you were in California I would totally encourage you because if you stay on this path you’ll burn out in 6 months and I could buy your stuff.

If you aren’t seeing anything on your dives it may be a case of not looking in the right places for the location, one of the best things a new diver can buy, after becoming competent with the basic dive gear, is a camera, not a GoPro but I regular camera, get close to the bottom and really look for the tiny stuff, there is likely a lot to see if you look.

As for tanks, buy another just like the one you have.

 

[Imla]

Personally, I think "because I want them" is a perfectly good excuse to get a twinset, and people should be more open to this argument as it usually win out about 99% of the time. Because we want to...

So to the tank bit... Doubling Fat12s sounds like a really bad idea from a trim/balance perspective.
In our neck of the woods, (Norway, cold, dark, murky, wonderful) the norm is D7 300bar, D8,5 232Bar (However these are so tall that they would cause issues with anyone shorter than 175cm), Normal Slim D12s and D18s.

Of these tanks the most used combo is D12 232 bars. They give a superb sense of balance in the water.

D10s, DFat12s and D15s are all known to be prone to troubles with trim and balance and for being unreasonable heavy on land compared to benefit in the water.

I would never buy another like the one you have. You will find that balance with 2 is different than with one.

 

[AfterDark]

As long as you asked, IMO the much maligned back mounted independent doubles are the way to go. Here's why IMO:

ID's are more practical than SM for OW diving from shore or a boat. A personal preference mostly but I was more comfortable with BM, having tried SM with factory reps on several occasions.

If you dive BM now there isn't much to learn as opposed to SM. LDS and instructors don't like this part.

ID's do not require the large $$$ lay out that SM does. Depending how much gear a diver has accumulated ID's could have a very low start up cost. The LDS don't like this part.

ID's provide the diver with 2 independent bottles, built in redundancy no pony bottle required.

ID's are easy to handle on land because out of the bands they are of course singles.

ID's provides the diver with single tank use without owning many tanks and the cost that entails. (Hydros, VIPS. O2 cleaning.)

ID's eliminate the need for a manifold although not likely to fail, a possible failure point none the less, if for nothing else than O-rings. Divers with restricted shoulder mobility can appreciate this, I know I do.

A major downside is that the diver could be restricted to access to only 1 tank if a catastrophic failure occurs on the other tank. Attention to air management is required especially the last half of the dive keeping in mind that both tanks should not be drained past the point of providing enough gas for a safe return to the surface.

Good luck

 

[Storker]

I have a 12.2L Faber compact steel (the short, dumpy one) and absolutely love the mofo, though it is heavier than I'd prefer when out of the water

If you're thinking about a twinset to avoid changing tanks, you'll need twice your current rig's gas capacity. Problem is, a D12 set weighs roughly twice as much as a single 12. If you think a single 12 is heavy, you probably don't want to schlep a D12.

Heck, many of the techies around here who routinely dive D12s prefer a smaller twinset like a D8.5 when they're diving NDL. But they have to refill during the SI.

 

[halocline]

Twin steel tanks with bands and manifold are usually VERY negative in the water, especially when full. I would be very careful about using them with a wetsuit. A BC failure could be end of you. Did you mention whether you're diving wet or dry?

I dive twin AL80s quite a bit, and I can tell you from experience that they are much more work on a boat than any single tank. Doubles are more work in general out of the water. Twin AL80s are fine in the water, maybe about 10lbs negative full (I never really checked, just guessing) and about neutral empty, maybe a bit negative. Steel 100s would be around 25 lbs negative full, I would guess, maybe more.

So to answer your question about which tanks to get, definitely do NOT get twin steels if you are in a wetsuit. Stick with AL80s. Twins are falling out of fashion so I'm sure you could find a good deal on a used set.

Sidemount will likely be your better option if you don't want to fiddle around on land, but believe me, you'll more than make up for that fiddling in the water getting everything adjusted and set.

Neither of these options are nearly as simple and effort-free as just using single tanks. People tolerate carrying doubles or messing with sidemount because they need all that gas and some redundancy. You seem to think that it will be easier or less work to dive with two tanks than it is to simply change tanks. That is not true at all.

 

[hxtk]

I can't comment on tank choices as I am from the US and my options are very different to yours. I don't consider the transition to backmount doubles to be a huge deal if you're starting on single tank, at least if you're going from a GUE singles configuration to a GUE doubles configuration. Doing valve drills will take some training, and relying on the ability to do valve drills will take even more, but just treating them as a big single tank, I was able to get used to them in a few hours of pool time.

One thing I cannot recommend enough is going to the gym and getting under a barbell. If you're not already doing a heavy-lifting routine such as Starting Strength, 5x5, etc., the difference that a few months or even weeks of doing one makes is night and day.

As others have brought up, it is important to test the assumptions you rely upon for safety, and there is a lot of negative buoyancy involved with a full set of doubles. I like to ensure that one failure can cause me to abort a dive and a second failure can occur while I am aborting the dive and I will still be able to surface safely. This means testing whether you can, in practice, swim up the negative buoyancy of your doubles filled as they would be at the start of a dive without the benefit of your wetsuit's buoyancy if you are diving wet. If you are diving dry, this means ensuring you are proficient at using only your wing for buoyancy, you are proficient at using only your suit for buoyancy, and your buddy is able to assist you if both your suit and wing should fail. Of course there are other procedures you might choose for dealing with various buoyancy failures; those are simply the ones I have chosen and have tested that I can safely rely on for the sake of example.

 

[MichaelMc]

Switching between types of tanks is a pain, though so is lugging a second tank.... Lugging a second backplate and harness is likely easier, or an STA.

An option is independent doubles using whatever tanks that shop rents on site. But twice the weight to solve adjusting cambands between dives seems an odd tradeoff.

If you just want to try something cool, try AL40/LP50 doubles. They're about the weight of a single and only marginally more complex, yet give you a taste of doubles and redundancy, but are also only good for one dive.

Sidemount would be a diversion if you want that. But it has a fair bit of fiddling with how tanks get attached, bungeed, clipped/unclipped and hoses routed. If you can, I'd start with tiny ones, like the doubles. Or AL72s, which could give two shallow dives. Sidemount is my own preferred setup, but it is more complex than single tank, or tiny doubles. For sidemount, the easy tank progression might go AL40/LP50, AL72, AL80/LP85/HP100, which are all generally thinnish (and longish) for their size. Short and stubby is not usually recommended.