Tec Diving Journey / Seeking Advice

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hammerhead_sm

Registered
Messages
17
Reaction score
4
Location
India
# of dives
100 - 199
Hey everyone.

[Background]
I've been gradually progressing into the world of tec over the past decade. Starting as a recreational diver, I've accumulated ~400 dives across Asia and earned my divemaster certification to build better awareness underwater and help local dive groups. What really draws me to diving is the 'skill' of it —both theory and technique—and I've consciously worked to become a 'better' diver by learning from and emulating more experienced divers and instructors.

This naturally led me to tec diving. It wasn't just the deeper depths and longer durations that appealed to me, but the seriousness of it—the intentionality and complexity. After completing my Intro to Tech at Gili T, it took another year before I enrolled in TDI ANDP in Koh Tao. ANDP proved challenging, if not only because I decided to do it in sidemount configuration - without any prior sidemount experience. The other students were using sidemount for the course, and the instructors suggested we all use the same setup to learn as a team. Though they did offer me the option of doing the course by myself on twins. I didn't know how steep the learning curve would be, so I spent a few days learning recreational sidemount and then starting the course. Despite having about 250 dives under my belt (all backmount), I struggled a lot, but ultimately demonstrated enough growth to get certified.

After certification, I didn't tech dive again for another year. This February, I returned to the Gilis and switched to twins instead of sidemount. I did a check dive and two tec fun dives. Though my guide seemed happy with my skills and trim, I felt like I was struggling. This year I've decided to pursue tec more seriously and plan to drive down to the coast every six to eight weeks, and log 4-5 dives on each trip. Hopefully by the end of the year I'll have another 20 or so dives under my belt.

My goal is to build the skills and confidence to do the TDI Trimix 75 next.


[Current Challenges]
I completely understand that being tec certified only means that I have the bare minimum skills and qualifications to responsibly dive to the certified depth. I am under no illusions otherwise. And after 5 post cert tech fun dives, I'm still not happy with how I feel during deco stops and the dives in general. I find it difficult to maintain a precise depth—my breathing causes my position to oscillate by around 0.5m - 1m across breath cycles. Sometimes I drop down by 0.8-1m or rise 0.5m above my target level. The 20-30 minute stops aren't exactly pleasant either. I feel wobbly and I feel at times my legs rising too high, requiring constant adjustment to keep them down. I could grab the reel and hold on, but that feels like cheating. Because I am not confident of maintaining my depth, I am staring at my computer for the entirety of the stop. Also because I feel like I'm struggling, I can't help but continuosly flick my fins to steady myself - despite trying hard to refrain - which makes me slowly drift past my buddy and then I need to helicopter turn to face him again - this repeats a few times through the dive. I really just want to stay put.

Even at the bottom, I'm not completely comfortable. Sometimes the BCD feels heavier on one side, and I feel the weight of the twins pulling me over. I've tried adding a drop weight on my waist d-ring to balance it, but I'm not sure it's helping much. With regards to my feet rising, I'm also using my recreational ScubaPro Go Sports fins, which probably aren't heavy enough. Not sure if jetfins or the like will solve for this.

I've asked my divemaster for tips - but he seems to suggest that I look just fine both at the bottom and at the stops. Without structured feedback I'm not sure exactly what to focus on in subsequent dives.

So I'm turning to this forum :) - I've attached Shearwater graphs from my most recent two dives below. I know there's a lot of scope for improvement and I would appreciate any feedback on how the data looks and what I should focus on in future dives to get better - and more important feel more in control, throughout the dive.

Thanks!


1743104057566.png


1743104127181.png
 
Don't dive deep air. Deep air is stupid. Are you doing your deco on air as well?

You are struggling because your initial instruction was lacking. Good for you to recognize that your skills aren't where they need to be. That attitude will keep you alive.

Do more shallow dives to get your trim and buoyancy right before venturing deeper. Find an instructor or mentor that knows what they are doing. Have them watch you and have them work with you to get you trimmed out properly.
 
Don't dive deep air. Deep air is stupid. Are you doing your deco on air as well?

Ah. I should have clarified. Across the dives I was in the range of 22 - 28% O2 - depending on the depth. Deco was 50% on a few and 80% O2 on the last one.
 
You sound like a good candidate for a GUE Fundamentals class. You feel like something is missing, and you want to be more proficient and comfortable in the water. A fundies class will get you squared away so you feel like you're in control, and give you the tools you need to keep improving.

Ah. I should have clarified. Across the dives I was in the range of 22 - 28% O2 - depending on the depth. Deco was 50% on a few and 80% O2 on the last one.
The issue is not the O2 content, but the gas density because there isn't any helium in the mix. Going past 40m on air or any EAN mix is pushing the recommended max limits for gas density.
 
Ah. I should have clarified. Across the dives I was in the range of 22 - 28% O2 - depending on the depth. Deco was 50% on a few and 80% O2 on the last one.
Don't dive deep nitrox. It's just as stupid as deep air.
 
A) learn to back kick
B) breathing slow & deep does not work when trying to maintain precise depth. Fortunately, you're not doing anything, so you don't need large breaths.

As you are laying in bed tonight, make note of your inhale volume and timing. Match that on deco. Adjust the wing to be neutral at end of exhale. You're likely at end of exhale for 2-4x the time you inhale.
 
Got same buoyancy issues with TecLine Jet fins - very light and some kind of positive during TDI ANDP, so always turns legs up on deco stops . Finally after course move all weights (triangle between tanks) from backplate to weight belt pockets and fill much better.
 
the good news is you can practice your sidemount skills in shallow water -lets say 12m - then go pro yourself to see what its happening with trim -500-1m variation sounds like you might be overweight - take off a kilo and practice - repeat at 6m

you will use the same skill set at 12m as you do at 50m so forget about depth and just get lots of time in the water

Im assuming your in a wet suit?

while in water theres a couple of tricks you can use with sidemount to see where your balance point is -if your head heavy push the tanks back under your arms a bit more or the opposite if feet heavy -

another trick if your feet heavy is to extend you hands out fully in front of you so that you are making yourself longer and changing the tipping point
once youve worked out where the weighting problem is you can make adjustments with your rig make small changes not macro ones eg move a weight 100mm back or forward - is it better out worse or move a tank back slightly if you try and move everything all at once it just gets confusing

@crofrog has a good essay/article on trim

20 Tec dives a year is barely maintaining you skill set - aim for more - tech diving is a mental shift - treat every dive as a tech dive regardless
 
Going deep is not an accomplishment.
You are posting your profiles instead of your dive plans.
Did you plan these dives or just chased the computer?
That is called "sportechnical" diving. Sport diving to technical depth. You are doing a technical dive only in the definition of technically, you are diving. But really, you are not not diving, you are performing a dive accident and failing.

Since your heart is in the right place:
Go to 3meters and practice frog kick, back kick and helicopter turns. No fins.
Do air share and time your valve drills. Then do it without a mask and fins.
Deploy a bouy on a reel from 3 then 10 then 15 meters in any trim. Deploy a second bouy on the same line.
Connect and disconnect your AL40 stages, then try 4XAL80s stages without mask and fins at 3 meters.
Can you switch gasses correctly? PADI NOTOX is one example.

Plan a dive with a simulated decompression.
Assemble gear with a checklist.
Do the dive with a watch and depth guage. No computer.
Can you hang at 6 meters with nearly empty tanks and maintain within 0.5 meters?

Don't take advice from strangers on the internet. I am dumb and incompetent.
 
Going deep is not an accomplishment.
You are posting your profiles instead of your dive plans.
Did you plan these dives or just chased the computer?
That is called "sportechnical" diving. Sport diving to technical depth. You are doing a technical dive only in the definition of technically, you are diving. But really, you are not not diving, you are performing a dive accident and failing.

Since your heart is in the right place:
Go to 3meters and practice frog kick, back kick and helicopter turns. No fins.
Do air share and time your valve drills. Then do it without a mask and fins.
Deploy a bouy on a reel from 3 then 10 then 15 meters in any trim. Deploy a second bouy on the same line.
Connect and disconnect your AL40 stages, then try 4XAL80s stages without mask and fins at 3 meters.
Can you switch gasses correctly? PADI NOTOX is one example.

Plan a dive with a simulated decompression.
Assemble gear with a checklist.
Do the dive with a watch and depth guage. No computer.
Can you hang at 6 meters with nearly empty tanks and maintain within 0.5 meters?

Don't take advice from strangers on the internet. I am dumb and incompetent.

You had Yosemite Sam as your IT, huh?
 

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