DIR- Generic Fundies as a first encounter with doubles

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Sorry I had missed the part above on 70 dry dives already. In that case you should be good, and really no reason not to go for doubles.

I do have the hypothesis though that you will end up with less gas in the suit after fundies than currently ;-) and with steel doubles you will need the wing a lot earlier than 18m, but all that you will learn in fundies. Enjoy the journey!
 
If you are certain that doubles and drysuit is the configuration you will be doing most of your diving in, then take Fundies in that configuration.

I wasn’t sure where I was headed with diving, and I had done about 200 dives in wetsuit and single tank when I took Fundies, so that was the configuration I took it in. A couple of years later, I acquired doubles and a drysuit and took a combined doubles and drysuit Primer course because it was a lot to change at once. It was a HUGE change. Three years later I’m still training for a Tech upgrade.

For you, it’s an easy decision. If you’re already comfortable diving in a drysuit, and your goal is to dive in doubles, then go for it. You’ll probably get a provisional pass the first time anyway, so I’m not sure I would bother with doubles Primer.
 
Hi

don't be too much intimidated by D12's.

I was in a similar situation as you are in now, I also thought that I will continue diving with my mono configuration after the class. However, my instructor convinced me to give it a try with D12's and primary light, just in case and as a good practice. First day in class, I had my first encounter with double wing and D12's ever. In terms of diving no problem, it just fellt good and more stable than the mono config I knew. My recommendation, go for it if you have the chance.

For the rest of the class, it was a very steep learning curve for me (OWD with 25 dives at the time), but one of the best experiences. I was so proud of me once I got my rec pass, and I am so happy that I did Fundies so early on in my diving career. Highly recommended.
 
I would not go into a class with a new piece of gear. You’ll waste time and could be distracted by making gear adjustments that should have been resolved before class.

Switching to doubles is relatively easy, but there’s still an adjustment period. You may need to fine tune your buoyancy, adjust your harness, etc.

A friend borrowed a set of doubles with harness from me to take intro to cave. He struggled and had a lot of unnecessary frustration. I told him to buy and dive before class, but he wanted to see if he liked it first. He dropped out. Lesson learned: Don’t take advanced classes in new or borrowed gear.
 
I would not go into a class with a new piece of gear. You’ll waste time and could be distracted by making gear adjustments that should have been resolved before class.

Switching to doubles is relatively easy, but there’s still an adjustment period. You may need to fine tune your buoyancy, adjust your harness, etc.

A friend borrowed a set of doubles with harness from me to take intro to cave. He struggled and had a lot of unnecessary frustration. I told him to buy and dive before class, but he wanted to see if he liked it first. He dropped out. Lesson learned: Don’t take advanced classes in new or borrowed gear.

All good points and solid advice. The slight difference here is that your friend compounded learning totally new skills on top of the doubles where is fundies IS a class to learn doubles. Every skill taught in fundies--buoyancy, trim, kicks, valve drill, s-drill, diver recovery, with the exception of dsmb is designed to help teach you how to dive the tanks you are using.

I support the get a little experience in them before class position. Diving doubles for the first time in fundies isn't terrible, but it does require a mindset that I am taking this class to learn as much as possible and probably not pass. It might be possible, but if a diver goes into class diving doubles for the first time and fully expects to pass the course, I would say they need an expectations adjustment.
 
Hi

don't be too much intimidated by D12's.

I was in a similar situation as you are in now, I also thought that I will continue diving with my mono configuration after the class. However, my instructor convinced me to give it a try with D12's and primary light, just in case and as a good practice. First day in class, I had my first encounter with double wing and D12's ever. In terms of diving no problem, it just fellt good and more stable than the mono config I knew. My recommendation, go for it if you have the chance.

For the rest of the class, it was a very steep learning curve for me (OWD with 25 dives at the time), but one of the best experiences. I was so proud of me once I got my rec pass, and I am so happy that I did Fundies so early on in my diving career. Highly recommended.
Words of wisdom right here. Don’t be intimidated is right, I used to think that doubles somehow “technical” and that’s just plain wrong. That sort of mindset isn’t good for progression. I’d say it takes only max 20 dives to get comfortable in doubles. For me it took more like 5. So much more stable. And if you think about it, a submarine has two ballast tanks for stability so why shouldn’t a diver have the same? Do the doubles first in a wetsuit, after a couple dives, try the drysuit.
 
Words of wisdom right here. Don’t be intimidated is right, I used to think that doubles somehow “technical” and that’s just plain wrong. That sort of mindset isn’t good for progression. I’d say it takes only max 20 dives to get comfortable in doubles. For me it took more like 5. So much more stable. And if you think about it, a submarine has two ballast tanks for stability so why shouldn’t a diver have the same? Do the doubles first in a wetsuit, after a couple dives, try the drysuit.

I disagree that doubles are easier to handle than a single tank. Having been accustomed to being able to turn any way I wanted in an instant, do barrel rolls if I wanted, and most importantly, stop at any depth and hold it indefinitely, trying to do those things with twin steels felt like trying to turn the proverbial aircraft carrier. Several years of practice later, arresting my ascent at a target depth by balancing a combination of heavy steels, a wing and drysuit still challenges me. Simply put, those massive tanks have momentum. Half the time I over or undershoot the target. Occasionally it totally gets away from me and I continue way past. From discussions with others aiming for similar precision (Fundies tech level), I know I’m not alone.
 
I disagree that doubles are easier to handle than a single tank. Having been accustomed to being able to turn any way I wanted in an instant, do barrel rolls if I wanted, and most importantly, stop at any depth and hold it indefinitely, trying to do those things with twin steels felt like trying to turn the proverbial aircraft carrier. Several years of practice later, arresting my ascent at a target depth by balancing a combination of heavy steels, a wing and drysuit still challenges me. Simply put, those massive tanks have momentum. Half the time I over or undershoot the target. Occasionally it totally gets away from me and I continue way past. From discussions with others aiming for similar precision (Fundies tech level), I know I’m not alone.

Interesting. I actually have more trouble in a single tank. I feel like it's significantly less stable. My muscle memory is totally keyed to big steel doubles and a drysuit, so I have some of the same problems you have, but in a single and a wetsuit. For example, I'm constantly dumping too much on ascents when I dive with my wife (she won't touch doubles or a drysuit). I think it's just a question of what you spend the most time in. 95% of my diving is in FL caves, the rest being the occasional T1 depth wreck. So the configuration pretty much never changes.
 
So much more stable. And if you think about it, a submarine has two ballast tanks for stability so why shouldn’t a diver have the same?
It is not subs have two tanks, we have two tanks, so we are stable. Subs shift water between their tanks. You do not normally pump air between doubles to adjust their mass.

And stability is a bit more about having ballast low. Plus subs have more than two ballast tanks. Plus trim tanks: fore, aft, port, starboard. And compensating tanks near the center.

(ETA: I have now reordered the sentences of my above paragraphs for clarity. Without changing their content. Putting the crucial difference first, then extra other issues later.)

tank1.png

Submarine Design: Unique Tanks On a Submarine

Now, if you want to talk about subs move mass and are stable. We can move mass/lead. Could that make us stable?? That would be an analogy that would work.

Quoting from that piece:
"Trim tanks are used to maintain the longitudinal center of gravity just under the center of buoyancy, so that the submarine can be maneuvered to a neutral trim condition."
 
I disagree that doubles are easier to handle than a single tank. Having been accustomed to being able to turn any way I wanted in an instant, do barrel rolls if I wanted, and most importantly, stop at any depth and hold it indefinitely, trying to do those things with twin steels felt like trying to turn the proverbial aircraft carrier. Several years of practice later, arresting my ascent at a target depth by balancing a combination of heavy steels, a wing and drysuit still challenges me. Simply put, those massive tanks have momentum. Half the time I over or undershoot the target. Occasionally it totally gets away from me and I continue way past. From discussions with others aiming for similar precision (Fundies tech level), I know I’m not alone.
Interesting but that’s unusual (at least from Ive heard). Doubles is a lot more stable but yes does require more oomph so proper jet fin style blades and good propulsion techniques are more necessary. I don’t think they “easier” than a single tank but for me at least, by the time you get to doubles your buoyancy and trim is decent so it’s not a hard transition. This is all presuming that the doubles are modified to you, if they’re not I’ve had it before where the cylinders were in a position where even if I was actively trimming out as much as possible, I was still at like 30 degrees and I couldn’t look horizontal as my head were bonking into the valves :D

Momentum on doubles? I’ve never found a notable difference but maybe you could be right. My understanding is that greater surface area (in trim of course) means slower ascending/ descending since it has to push a bigger body of water out of the way. While the wing is about 10lbs bigger so yes it will have 33% more lift compared to singles which means 33% more gas can expand when ascending.

I admire your honesty but drysuit and doubles definitely does take time to get used to. I know Im nowhere near close to having mastered it yet!
 
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