Starting in tec.

[grantmac]

I'm in basically the same place in terms of progression (maybe a touch further) and I'm going almost exclusively sidemount.
I've dove it off boats and in wrecks, I really don't see where the struggle is compared to BM. Perhaps if using very large tanks or needing to do negative entries with stages I might think differently but using AL80s or HP100s I just don't experience any issues.

 

[oya]

So many questions. . .

Let me see if I can answer them:

1. Twins - yes
2. Metric - better
3. Advanced trimix - yes, you are missing something.
4. Experience between deco and trimix. More than you have now. Ask again in a year.

Best response to any thread on Scubaboard of all time. I feel like this could, very possibly, be a canned response to so very many questions asked in many of the advanced sub-forums over the... what... 20+ years I've been watching.

VikingDives wins at Scubaboard!

 

[oya]

I have done more than a couple wreck dives and off hand I can only think of five or six that sidemount would be my preferred method. Most wreck diving involves a boat and BM is much easier for boat diving.

20 dives, while technically "more than a few" doesn't really count. Do your research, Tracy.

 

[CptTightPants21]

I'm just getting started in tec. I'm literally doing my e-learning now for TDI deco procedures. I'm seeing more of a focus on twins though I prefer sidemount. Is it worth the time to go through the twins procedures even though I don't think I'll use them? My goal is wreck penetration and sidemount seems to suite those needs better.

I'm also curious if there's a consensus on the imperial vs. Metric debate. I'm thinking with tec that I may have to go full metric and only do the conversions when communicating with others when necessary but otherwise doing all of the planning and math in metric and not mixing units (ask NASA about that).

It looks like the obvious path is adv. Nitro and deco followed by trimix then ccr. I don't see a use case for adv. trimix. Am I missing something?

Lastly what is the recommended experience level between deco and trimix? I know every instructor will have a standard that they are going to want. I'm just trying to level set something in the way of expectations. I know this training is a marathon and not a sprint and it's not a weekend. The experiences seem all over the place and it makes long term planning difficult.

As others have said, wreck diving typically involves diving off a boat and twins is much easier and more compatible with diving off a boat than sidemount.

Metric is a little easier, but you are better off learning imperial as the vast majority of divers you meet in the US and Caribbean will use it. There is probably less than 10% of divers who know metric in the US and even fewer can seamlessly transition and use it. Don't overly complicate things.

Plans are great, but in my experience scuba plans rarely last the test of time. I tell people to focus on getting more time under water, get deco certified, and then dive some more. Too many people treat it like a predetermined quest. A quest they complete in 3-4 years and then suddenly stop diving because they completed their quest.

 

[Tracy]

I tend to go the other way in regards to Metric. Starting technical diving is a great time to make the switch. Your diving life will be much easier if you transition. All of the calculations can happen quickly in your head.
It takes about 6 months of diving before you stop converting it in your head and just know where you are and what pressure you are seeing.
In this age of backup computers instead of backup slates, it is even easier. You can leave one computer in Imperial and one in metric until you get it down pat.
I recommend it to all my students, about half run with it, half don't. I can transition seamlessly bewteen them, so I don't care much either way.

 

[SmashMonkey]

It looks like the obvious path is adv. Nitro and deco followed by trimix then ccr. I don't see a use case for adv. trimix. Am I missing something?

I'm sort of like you. I just completed AN/DP/Helitrox and wondering if in the future to skip trimix and adv trimix OC and just switch over to helitrox CCR. Have you thought about adding helitrox to AN/DP and be able to dive up to 21/35 trimix on OC for virtually the same amount of training as AN/DP. For me it was a couple of hours of extra classroom , 1-2 dives, and $300. It's difficult to understand how narcosis affected me until I tried helitrox on identical dives to 135 ft. The best way I can explain it is the difference between watching TV at 720P right after waking up vs. 4K TV after a cup of coffee. Also gas density of air at 120 ft is 6g/L (how's that for mixing units?). I watched this presentation by Dr. Simon Mitchell before my course:

 

[GiraffeMarineSalvage]

If ccr is in your future then definitely learn doubles. Most honest instructors prefer to start ccr divers in bm units. Things are getting better in the sm ccr world but at this point in time sm ccr’s come with compromises that many new ccr divers don’t have enough knowledge to understand

Learning OC doubles is all good and fine, but if OP is confident in the future they want to dive depths/durations that CCR has dramatic benefits (or for other reasons like silent diving experience and increased closeness to marine life... and have budget to do so) then might as well take plunge to CCR earlier than would have been recommended when helium was cheap and CCRs were less refined than many now are...

Full disclosure: I only have experience with chestmount CCR and have not progressed anywhere close to a point where any of my dives would need a bailout CCR (instead of simply OC bailout), but one of my personal rationale for my first CCR being chestmount (as opposed to backmount/sidemount CCR dichotomy) is that if I were ever to get to a point of wanting/needing a bailout CCR for any potential distant future dive profiles it would come at a point that the unit I had the most experience with would be my bailout (ie in worst case scenarios would be able to naturally fall back to what was most familiar...). For me personally that meant buying a Triton CCR (but Choptina and Scubatron GMB are two other chestmount CCR options). YMMV of course.

 

[_john]

I've been watching the lecture videos about the physiology and I love the math. I'm a IT guy so math is my friend. The trimix formula is super cool and the gas mix and depth formulas are cool but the videos do a really great job of explaining why the formulas work are why they are important.

 

[VikingDives]

Best response to any thread on Scubaboard of all time. I feel like this could, very possibly, be a canned response to so very many questions asked in many of the advanced sub-forums over the... what... 20+ years I've been watching.

VikingDives wins at Scubaboard!

Thank you sir!

 

[VikingDives]

I tend to go the other way in regards to Metric. Starting technical diving is a great time to make the switch. Your diving life will be much easier if you transition. All of the calculations can happen quickly in your head.
It takes about 6 months of diving before you stop converting it in your head and just know where you are and what pressure you are seeing.
In this age of backup computers instead of backup slates, it is even easier. You can leave one computer in Imperial and one in metric until you get it down pat.
I recommend it to all my students, about half run with it, half don't. I can transition seamlessly bewteen them, so I don't care much either way.

I do all my planning in metric, but I generally dive in imperial... I can do either, but for ascents, I prefer the granularity of feet. I like to spend 10 minutes ascending from my 10 foot stop, 1 foot at a time, if conditions allow that.

But doing math in imperial - yuck.