extending a recreational dive into short deco?

[scubadada]

Intro to tech--and I'm not referring specifically to the TDI course of that name, which I haven't taken, but rather the concept of learning the rudiments of what goes into diving beyond rec limits--should be as much about the mental aspect/mindset of tech diving as the mechanics. I've been slowly heading down this path myself and absorbing this aspect little by little. Take it slow. One can probably learn the mechanics of it pretty fast, but maybe the mental aspect/mindset/philosophy/Zen, etc., takes time to sink in.

Wow, I think I may have known you in the 1970s.

 

[Reku]

You need the mindset for tech diving. You need to be prepared to deal with the fact that the dives you are doing are considerably more dangerous then a recreational dive. If you had an accident underwater where your buddy was mortally injured or gone, would you be able to stay calm and do the necessary deco and not freak out and bolt to the surface. Everything is a calculated risk.

 

[boulderjohn]

I'm having trouble understanding the point of this thread. Is the OP asking if it is OK o do a solo tech dive once you are certified? Is he asking if it is OK to start a dive with buddies and then leave them to do a solo dive?

 

[Reku]

I'm having trouble understanding the point of this thread. Is the OP asking if it is OK o do a solo tech dive once you are certified? Is he asking if it is OK to start a dive with buddies and then leave them to do a solo dive?

I was under the impression that he was asking if it was OK to start a dive with buddies and then transition to a solo dive if the opportunity raised and then go into light deco to look at whatever made it worth staying past NDL and soloing.

His OP does not state if he was certified in decompression but later on in the thread he states he would be taking an ANDP type course shortly.

 

[tep]

If you start as a team, you finish as a team. ("Never leave your wing man, Mav!")

Plan your dive, dive your plan. If you plan a rec dive you do a rec dive. If you plan a deco dive, you do the dive as planned. As a team.

If you start as a rec dive, and end up in a deco dive, then you a) didn't plan properly, or b) something happened, or c) you were lying to yourself (and your buddy) and it was really a deco dive from the start. Your buddy just didn't know it.

If you are doing a solo dive, have a nice time, but don't pretend to be my buddy. I don't object to solo dives at all, I just want to know what I'm getting into before I get into the water. Same for rec vs deco.

 

[boulderjohn]

So let me play a bit f a Devil's Advocate here.

A few weeks ago I did a beginning level trimix dive with a student. It was not planned to be extremely deep. While we were planning the dive, two friends who were tech (but not trimix) certified were planning a very similar (but not as long) dive. We decided to go to the same location. We planned the dives carefully and followed our plans carefully. We were two distinct teams diving to the same depth in the same place--but anyone looking at us without hearing the plans would assume during most of the dive that we were a foursome. They started their ascent before us, but really not all that much. Because we were using two decompression gases and they were using one, we did not finish all that far behind them.

So I have some questions.

1. Was there anything wrong with what we four divers did on that dive?
2. If I had been a solo diver doing the same dive instead of an instructor diving with a student, would that have been OK?
3. If 1 and 2 are OK, how different is that from what the OP wants to do?

 

[tursiops]

So let me play a bit f a Devil's Advocate here.

A few weeks ago I did a beginning level trimix dive with a student. It was not planned to be extremely deep. While we were planning the dive, two friends who were tech (but not trimix) certified were planning a very similar (but not as long) dive. We decided to go to the same location. We planned the dives carefully and followed our plans carefully. We were two distinct teams diving to the same depth in the same place--but anyone looking at us without hearing the plans would assume during most of the dive that we were a foursome. They started their ascent before us, but really not all that much. Because we were using two decompression gases and they were using one, we did not finish all that far behind them.

So I have some questions.

1. Was there anything wrong with what we four divers did on that dive?
2. If I had been a solo diver doing the same dive instead of an instructor diving with a student, would that have been OK?
3. If 1 and 2 are OK, how different is that from what the OP wants to do?

What is different is that you were diving your plan, in all your examples.
The OP is diving his whim, if he sees a shiny thing and gets distracted by it beyond his dive plan.

Like many in this thread, I have no issue with solo or deco (if trained and equipped for it), but I do have an issue with just winging it. The part about buddies is kind of irrelevant, so long as they know you are not one of their buddies.

 

[boulderjohn]

What is different is that you were diving your plan, in all your examples.
The OP is diving his whim, if he sees a shiny thing and gets distracted by it beyond his dive plan.

Like many in this thread, I have no issue with solo or deco (if trained and equipped for it), but I do have an issue with just winging it. The part about buddies is kind of irrelevant, so long as they know you are not one of their buddies.

So you are saying the difference between OK and not OK and the OP's scenarios is whether or not the whole thing is planned. Is that correct?

 

[Reku]

So let me play a bit f a Devil's Advocate here.

A few weeks ago I did a beginning level trimix dive with a student. It was not planned to be extremely deep. While we were planning the dive, two friends who were tech (but not trimix) certified were planning a very similar (but not as long) dive. We decided to go to the same location. We planned the dives carefully and followed our plans carefully. We were two distinct teams diving to the same depth in the same place--but anyone looking at us without hearing the plans would assume during most of the dive that we were a foursome. They started their ascent before us, but really not all that much. Because we were using two decompression gases and they were using one, we did not finish all that far behind them.

So I have some questions.

1. Was there anything wrong with what we four divers did on that dive?
2. If I had been a solo diver doing the same dive instead of an instructor diving with a student, would that have been OK?
3. If 1 and 2 are OK, how different is that from what the OP wants to do?

1. Looks pretty clear cut to me - nothing wrong here.
2. It would of been OK because you planned for a solo dive to happen with 100% certainty.

3. 1 and 2 are correct, from my understanding OP wants to plan a rec dive and do that dive with 2 of his buddies - however IF he sees something worth going into deco for he will signal his buddies and go look at the thing. Thereby going into unplanned deco. He wants to dive a rec plan and throw some deco on the side if he sees a reason to.

I personally don't like changing a dive while the dive is underway. It's either a planned deco dive or it's not. It's either a planned solo dive or it's not. You shouldn't abandon your team and go solo just because you see something interesting.

However:

If OP plans his dives in a way that his buddies know that he may leave them and go solo and into deco - I would be fine with that. It's all about prior planning - as long as his plans include potentially leaving his team and going solo than it would be OK. If everyone agrees and knows the plan - it can work.

The difference is that one plan includes deco and solo while the other plan does not include deco and solo.

the first dive plan changes mid way (bad)
the second dive plan never changes. (good)

YMMV/IMO/etc etc this is what I think disclaimer.

 

[doctormike]

I think that since the OP isn't tech certified yet, he didn't pose the question as precisely as he might have, so it's causing some confusion.

I have no problem with a well trained and experienced tech diver doing a planned deco dive, with part of the time spent with a buddy team doing a rec dive. But that deco has to be planned, since if you just decide to stay arbitrarily longer after the NDL, you don't know if you have enough gas to complete your deco requirement.

Sure, a very experienced tech diver with a full set of doubles and a slung 80 of deco gas intuitively knows that he can incur 10 minutes of deco and have the gas to do it, without explicitly calculating his gas requirements. But that's sloppy, and not the way that a new tech diver should be thinking. He should figure out how long he can stay at the deepest depth (limited by his back gas and his deco gas, INCLUDING a lost gas scenario), and then work backwards. Once he has that plan written down on a slate - sure, fly the computer, stay above the bottom depth that you used in your plan, watch your run time, and have fun.