Coldwater diver with some basic BM tec training, looking to enter world of SM, need BC advice

[wetb4igetinthewater]

What you're saying doesn't not make sense but what training agency teaches this way? Since you mention "rock bottom" should I assume UTD?

The other thing I guess I'd ask is when you dive this way, does your buddy also carry one 50%? Only then would I say it makes sense since you theoretically deco together if you're using the same GF, etc etc. I mention this because the guys I do my tec dives with are all very willy nilly. Everyone's using different equipment set ups, different GF, different mixes, it makes no sense to me but they don't seem to mind. And since I'm either the student or the newbie, I'm not really in a place to speak up. But at the same time, I don't have anyone else to tec dive with.

I'd recommend taking a step back to work on foundational dive skills, namely GUE fundies from 8 Diving in Des Moines. It might be a cold shower for you. It was an ice bath for me. Whether you agree with the entire philosophy or not, doesn't matter. Your basic diving skills will improve. Your awareness will also improve.

I would not do tech dives with people with whom I do not have gasses matched. I might as well dive solo (which I only do recreationally on OC).

 

[Marie13]

Hm, maybe I should rethink this before buying a SM BC. Seems like in the end it will just make my life more difficult, not the other way around.

Are you shore or boat diving? That wasn’t particularly clear.

 

[rjack321]

What you're saying doesn't not make sense but what training agency teaches this way? Since you mention "rock bottom" should I assume UTD?

The other thing I guess I'd ask is when you dive this way, does your buddy also carry one 50%? Only then would I say it makes sense since you theoretically deco together if you're using the same GF, etc etc. I mention this because the guys I do my tec dives with are all very willy nilly. Everyone's using different equipment set ups, different GF, different mixes, it makes no sense to me but they don't seem to mind. And since I'm either the student or the newbie, I'm not really in a place to speak up. But at the same time, I don't have anyone else to tec dive with.

Rock bottom is a generic scubaboard term for "the minimum amount of gas to get you and an OOA buddy from the moment of the OOA up to your next gas source" (which might be your next gas source or might be the surface). Different agency's have different terms for that. It's measured in cf or Ls (if you're metric) and is independent of your cylinder size. It also gets a lot more complicated in SM fairly quickly.

And yes, with 10-30mins of deco in the 90-150ft range why are you bringing 2 deco gases at all? In many cases that could be done on an AL40 but there's no much reserve with that. A single 80 of 50% is fine

 

[Scuba Shibe]

Are you shore or boat diving? That wasn’t particularly clear.

Shore 100% of the time.

 

[Marie13]

Shore 100% of the time.

If you were boat diving, I’d say forget SM. But if you’re shore diving, go for it. I will say you need to spend time fussing with it. Not plug and play like BM.

 

[Wibble]

What you're saying doesn't not make sense but what training agency teaches this way? Since you mention "rock bottom" should I assume UTD?

The other thing I guess I'd ask is when you dive this way, does your buddy also carry one 50%? Only then would I say it makes sense since you theoretically deco together if you're using the same GF, etc etc. I mention this because the guys I do my tec dives with are all very willy nilly. Everyone's using different equipment set ups, different GF, different mixes, it makes no sense to me but they don't seem to mind. And since I'm either the student or the newbie, I'm not really in a place to speak up. But at the same time, I don't have anyone else to tec dive with.

I know my point would be that you MUST learn to walk before you run.

You've been signed off to carry that gas. Pure O2 doesn't take prisoners and is a gas that must be treated with caution.

To get used to flying on your own without an instructor is best done gently. 50% to start with (and a matching buddy). Then you can get onto that gas at 21m/70ft and should your buoyancy fail you, you can drop down a bit without worrying unduly. With 100% it's strictly 6m/20ft and a 3m sink pushes the PPO2 up to 1.9; way way too high.

Same with two cylinders. Just don't in the beginning unless you're taking low-levels for practice (50%).

The tip with ALL training is to build up your practice skills after the course until you're really comfortable. Definitely do not do a pinnacle dive until you're really happy with your skills.

---

Personally I've always hated 100%. It strips your lungs, it's very sensitive, it's a pig to get high pressure oxygen and it's only available from 6m/20ft. 80% is much much easier: it's kinder to your lungs, available as a top-off, you can get on it at 10m/33ft, and it's just as good for decompression as 100% but a lot safer.

Of course others will disagree with that, but they're wrong. Nerr.

 

[wetb4igetinthewater]

If you were boat diving, I’d say forget SM. But if you’re shore diving, go for it. I will say you need to spend time fussing with it. Not plug and play like BM.

Some sites in the area, like Octopus Hole, I'd rather not have a twinset on my back to reach. Even Day Island Wall, I prefer to carry my cylinders and camera gear separately down to the water but it is doable with doubles. I just don't like to punish myself when I go diving.

 

[PR_SMITH]

I dive dry, with 2x HP100's with the Katana2 rig. I have my bungees rigged like this:
Works really well, the bungee setup makes donning the tanks much easier, especially with drygloves.

 

[Marie13]

I dive dry, with 2x HP100's with the Katana2 rig. I have my bungees rigged like this:
Works really well, the bungee setup makes donning the tanks much easier, especially with drygloves.

I have a new DR Nomad XT. I don’t use the ring bungees. However, I did leave the ring on the bungees and use it as a handle to pull the bungee out to get it around valve hand wheel. Works pretty nicely.

 

[Walde]

I dive dry, with 2x HP100's with the Katana2 rig. I have my bungees rigged like this:
Works really well, the bungee setup makes donning the tanks much easier, especially with drygloves.

Some don't like metal to metal connections, that's metal to metal to metal to metal to metal, wonder what those people think about that.