Master Diver Certification

[Dive Bug Bit Me]

I pulled out my RDP tables for air. Per the dive profile, we spent about 5 minutes at 120'.
Ending with pressure group B. NDL is 13 minutes.
Tables incorporate a lot of safety margin.

Do you like this data better?

Cetus, when I was 80 dives experienced and had no tech training, I did similar dives to the one you describe, plus also a cave or two. A few hundred dives and some training courses later I now understand that my initial tech success was based on both the skills I had at that stage and a degree of luck. I just did not realize the importance of luck in those dives until much later.

You do not realize what you don't know and it's not found in any book. That is what good tutorage under an experienced instructor brings.

In respect of your question above, it's not a game of finding a set of standards that retrospectively justify your dive. If you had surfaced from the dive with 23 mins showing on your computer, either you bent or you didn't. My inclination is that you were likely to bend and therefore I stick with my assessment of this as a technical dive.

Just go do the training for the type of diving you want to do. My suggestion is that until then, you keep yourself within the realms of what you have been trained to handle.

 

[Jim Lapenta]

Planned with v planner, then switched to RDP mid dive? Why didn't you use the contingency plans that v planner allows you to make? And then stick to those? Tables theoretically have a safety margin in them. This clearly was not a properly planned dive and why there is training available for such dives. You'll also find that the tech dives that are done in the beginning are not multilevel dives. They are planned and executed as square profiles with planned decompression stops at regular intervals that you have a set schedule for. When the plan calls for leaving the bottom at 7 minutes it does not mean 7:01. And then when you are supposed to be at your first stop at 9:00 or whatever you are there. It is not a multilevel dive as covered in recreational mutlilevel courses. Those have room to play. On tech dives unless you need to deviate you don't period. And if you do it's to the plan you have made beforehand. Not on the fly unless it's a dire emergency.

This is why people are upset. The lack of proper planning and the attitude towards it. You're playing tech with recreational methods. That's a good way to get bit. And even worse get your kid bit.

 

[TSandM]

Cetus, don't be ingenuous. The RDP is limits for square profile dives, and assumes you will do a DIRECT ascent at the end of your bottom time, at at least the recommended rate of 30 fpm, with a safety stop at 15 feet. You CANNOT call the gradual mosey up the terrain you did a direct ascent, which is why tables end up being so darned conservative if you try to fit terrain-based dives into them.

You went into deco. You went substantially into deco by the model you were following, which was your computer. I'm not even sure CMAS would consider that a pure recreational dive, and they include some decompression training in their advanced recreational curriculum.

Look, I know Monterey. I know the dives you're doing. I know why people in Monterey get scooters, and why they end up doing tech training. The terrain at Lobos virtually demands it. Stop trying to defend what you are doing, which has elicited a rare thing on ScubaBoard, which is consensus that it is unwise. You have access to the training to do what you are doing properly and safely, so get it. Whether these dives are wise for your growing, 14 year old daughter, is not really known, but there are reasons to to view them as dubious. The dives you are doing are great dives and perfectly safe and reasonable, if they are done properly and with proper training.

 

[bpotkin]

Cetus,
First, congradulation on your MDC! I also dive with my Daughter (19 years old) and my 24 year old Son.
I unfortunately do not understand the ins and outs of some of the issues in this tread but would like to
give you some advise as If you were my Brother or close friend. As a pilot and a fellow diver I would like
to point out *hit happens that is out of your control. I would be proud of you and your Daughter's
accomplishments but at the same time.... take it easy... and error on the side of being too conservative

 

[AfterDark]

I suggested no such thing nor would the average person comprehend the statement as such.



An element of the equation that clearly escapes you is the term student. The OP is progressing as his and his daughter's own teacher for which he is clearly ill equipped. No longer is he in the role of student.

We're all students, 42 years of diving and I'm still learning. The OP is learning the same way thousands of divers did, by diving. I haven't got any deco certs. When I learned deco there was no nitrox, mixed gas wasn't used for sport diving and there were no certs. So I've been happily violating standards for some 30 years now. Living in an area where I could access 200FSW from a shore diving helped a lot.

 

[Jim Lapenta]

Were you doing it with your 14 year old daughter or son along for the ride?

 

[scubadada]

Sorry, I'm still stuck on how 23 minutes at 10 feet and 7.5 minutes at 20 ft simply became 5.5 minutes at 20 ft at the end of the dive. I must be a dive idiot as this simplly does not make sense. Help? What happened to the shallow obligation?

 

[Jim Lapenta]

It went away via the magical properties of the RDP that uses that as the default when someone doesn't know what they are doing, screws up, or just decides to ignore the original plan and their computer.
Ask many of the DM's and even some instructors who think this is what you do when you blow your NDL's. Saw it told to an AOW class right before their deep dive.
Remember this is all fun, meeting new people, doing new things, and no one gets hurt. At least that you'll be told about.

Sent from my DROID X2 using Tapatalk 2

 

[TSandM]

The 23 minute obligation assumed a direct, 30 fpm ascent. As the divers moved shallower, they offgassed to some degree, and reduced their deco obligation. Although I have to agree that most computers will clear the deeper time and keep the shallow time, but I'm not familiar with the model being used by this computer at all.

 

[Dive Bug Bit Me]

We're all students, 42 years of diving and I'm still learning. The OP is learning the same way thousands of divers did, by diving. I haven't got any deco certs. When I learned deco there was no nitrox, mixed gas wasn't used for sport diving and there were no certs. So I've been happily violating standards for some 30 years now. Living in an area where I could access 200FSW from a shore diving helped a lot.

42 years ago there were many pioneers to our sport. They were learning new things. Many died so that we could learn techniques and science that were unknown at the time. Fortunately many more lived! In many ways I admire a lot of the early pioneers.

Today, risking death to learn something that is readily available from instructors seems a bit foolish.