Let's do an easy dive

[Bob DBF]

@JohnnyC beat me to the point that the problem is not using more of your air, but where you decide to use it. Using it in the middle of your dive is not prudent, but at the end, in the shallows, near the exit would be acceptable. When you get a chance look into gas planning which will give you more information than you want to know, my post is the Cliff Notes version.


Bob

 

[lowviz]

That is where I was going also.

Use thirds for OW but become aware that there are better ways to plan. Start putting those plans into practice in AOW.

@Bob DBF I don't see your notes, but these are the ones that I usually recommend: NWGratefulDiver.com

 

[Dizzi Lizzi]

Ahhh, Ok, i get that. Makes sense. Thanks.

Ahh ha of course RMV is here

2nd edit. I did realize that I could use up that air near the entry but frankly I'm usually cold, a little tired and ready to get out. My dives last about 45 min average. I wear 7ml with all the accouterments.

 

[JohnnyC]

I wasn't trying to be harsh or insulting. I apologize if it came off that way.

As the OP said, her understanding is that you use 1/3rd to do your thing, 1/3rd to get back out, and the remaining 1/3rd for "just in case." In a perfect world that's true, but really the only place where it actually works is in a shallow no-flow scenario where your travel time in and out is actually equivalent. She's using the last 1/3rd to account for current, which is where that particular misunderstanding lies. As she found out, she was nowhere close to where she needed to be when she reached the end of her 2/3rds. In open water diving, as long as the surface is the 2/3rds mark that's fine, it might require a surface swim but really that's simply an inconvenience, or depending on conditions it may be a serious issue.

The problem with simply following the rule of thirds is that in many scenarios it's just not conservative enough. In open water NDL diving it's not usually so much of an issue, but it's good to understand where it falls short anyway.

@Dizzi Lizzi check out this link. It's a good primer to get you really thinking about gas management.

Rock Bottom and Gas Management for Recreational Divers

 

[Dizzi Lizzi]

@JohnnyC not taken that way Hey you said i was ahead of the curve, thanks for that. More homework.
Edit. Hard homework!! I will have to save this one for later it's a little advanced for me and overwhelming. But its printed and in my read pile. I will start on NWGrateful divers article first.

 

[gfaith]

@Dizzi Lizzi

The article by Bob (NWGrateful) has a pdf link on the last page. It is well worth saving and review from time to time. By the way I appreciate you write-up an candor.

 

[Dizzi Lizzi]

Already printed along with a few more articles.

 

[2airishuman]

In open water diving, as long as the surface is the 2/3rds mark that's fine, it might require a surface swim but really that's simply an inconvenience, or depending on conditions it may be a serious issue.

I have a list of contingencies I prepare for on any open water dive. One planning item is to determine the maximum time until rescue in the event that I have to surface away from my chosen exit point. Then I prepare to stay safe at the surface for that period of time. That preparation involves, generally, some combination of exposure protection, flotation, and signalling.

Any dive where you can't end the dive and surface safely at any point, and stay safe at the surface, isn't really an open water dive, is it?

 

[JohnnyC]

I have a list of contingencies I prepare for on any open water dive. One planning item is to determine the maximum time until rescue in the event that I have to surface away from my chosen exit point. Then I prepare to stay safe at the surface for that period of time. That preparation involves, generally, some combination of exposure protection, flotation, and signalling.

Any dive where you can't end the dive and surface safely at any point, and stay safe at the surface, isn't really an open water dive, is it?

You want to argue over the semantics about what makes an open water dive? How many non-open water dives have you done and what made them non-open water dives? I'm curious to see what your definition of an open water dive is, and how it relates to the OP's concerns over her dive.

 

[2airishuman]

You want to argue over the semantics about what makes an open water dive? How many non-open water dives have you done and what made them non-open water dives? I'm curious to see what your definition of an open water dive is, and how it relates to the OP's concerns over her dive.

I'm confused, JohnnyC. Do you believe a dive where the surface isn't safe is really an open water dive? Or are you just looking for another opportunity to talk about how many more dives you've made than I have? I'll make it easy for you. I'm a fool and my opinions are of no consequence. There.