The Rule of Thirds.

[Uncle Pug]

1) What is it?

2) What dives require the rule of thirds?

3) When is the rule of thirds not enough?

4) When is the rule of thirds too much?

5) What is the rule of halves?

6) What is rock bottom?

7) What dives require only rock bottom?

 

[Soggy]

Uncle Pug once bubbled...
1) What is it?

Use 1/3 of your gas for the dive...whether that be going into a cave, wreck, or moving away from shore...1/3 coming back, and leave 1/3 left for emergency.

2) What dives require the rule of thrids?

Anything involving an overhead environment or at great depth. I prefer to use the rule of thirds (or something close) when doing shore dives so I don't have to swim 45 minutes on the surface...though I seem to end up doing the swim of shame quite a bit these days. :crawl:

3) When is the rule of thirds not enough?

If you're a hoover on air consumption or have deco time to consider.

4) When is the rule of thirds too much?

Simple/relatively shallow boat dives where you are anchored right above the site and will not be moving far from the line. In this case, as long as you have enough air to find the line and come up, you're all good. I still try to reserve a little extra air just incase I have any current to deal with.

5) What is the rule of halves?

6) What is rock bottom?

7) What dives require only rock bottom? [/B]

I don't know the answers to these questions, so I can't give my opinion .



:jessica:



Ok, there was no reason for the above icon...I just wanted to look at Jessica Rabbit.

 

[Lemonade]

For 1), 2), 3):
While diving in overhead environments (wreck penetration, caverns, caves) the rule requires you to turn back when 1/3 of your gas supply is used.
1/3 - in, 1/3 - out, 1/3 - for "oh, sh.." situation

 

[Uncle Pug]

Correct answers will be given at the end of the day for self grading.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Maybe I should have made this multiple guess or even true and false

 

[Spectre]

AaronBBrown once bubbled...

The Grand Pugster posed for discussion...
3) When is the rule of thirds not enough?

If you're a hoover on air consumption

If you are a hoover, that's already taken into account with your rule of thirds. [your 1/3s are just different].

rule of thirds is not enough when it will take you more gas to return than it would be to enter. Examples would be dealing with currents, or if you are planning on hunting a giant octopus, or anything else that might cause you burn more gas on your return.

Deco diving falls into this, as well as being considered an overhead environment. You don't exit the overhead environment until your deco stops are completed.

Of course, if your buddy is a hoover, your remaining 1/3 isn't going to get them out!

 

[Soggy]

Spectre once bubbled...

Of course, if your buddy is a hoover, your remaining 1/3 isn't going to get them out!

This is actually what my intent was. I don't even factor in the idea of solo diving. I ain't going to be doing it!

 

[AquaTec]

1) What is it?
it is the calculation used to figure gas requirements for a dive.
some examples. cave 1/3 in - 1/3 out - 1/3 for emergencies allowing for flow in the cave [being that turn pressures are equal] deep; used for bottom gas. 1/3 for 50% of your bottom time 1/3 for the other 50% taking into aco**** travel time to and from your gas switch, 1/3 for bailout. [again accounting for turn pressure differences]

2) What dives require the rule of thirds?
any dive you can not accend directly to the surface.

3) When is the rule of thirds not enough?
when your turn pressure is less than a third of your gas

4) When is the rule of thirds too much?
when you are doing dives that allow a direct accent to the surface. durring deco - use rule of halves

5) What is the rule of halves?
durring deco

6) What is rock bottom?
I am not familure with this term, I will guess that this is the minumium pressure in your tank. say the end of your 2/3's

7) What dives require only rock bottom?
well if my above guess is correct then the same as answer #1

 

[JimC]

1) What is it?
Use only 1/3rd of the gas supply 'in', leaving 1/3rd for 'out' and another 1/3rd for emergency.


2) What dives require the rule of thirds?
Any penetration or overhead dive.


3) When is the rule of thirds not enough?
Almost everywhere its used, its not enough. Suffering gas loss at the 1/3rd mark may very well not be enough when you add the stress of having the gas loss.


4) When is the rule of thirds too much?
Any "OW" dive, where esa is posible and worst case accent is well covered by a lesser reserve.


5) What is the rule of halves?
A good way to kill you and your buddy? I'd guess its use 1/2 in and 1/2 out.. with no reserve.


6) What is rock bottom?
Abosulte lowest gas amount at the turn. For a 3rds dive its the first 1/3rd tank hit. Turn now, or your in major doodoo if something breaks.


7) What dives require only rock bottom?
Mayhaps a 6foot deep swimming pool. All dives require more gass planing than rock bottom.


Wonder how I scored.

 

[O-ring]

5) What is the rule of halves?

Aquatec is right...with deco gasses to cover your buddy in the event he loses a 70' bottle or an o2 bottle.

6) What is rock bottom?
The minimum amount of gas to get you and your buddy to the surface from your deepest depth including all stops, slow ascent, etc. In a deco situation, it is generally how much it takes to get off bottom and through deco (or to your first gas switch if you have a deco gas)

7) What dives require only rock bottom?
Dunno...I wouldn't cut it that close on any dive.

 

[Former FLL Now MSP Diver]

O-ring once bubbled...
Project Director
Millbrook Zebra Mussel Project (MZMP)

When did you get the new position?

Marc