Dive Planning Thread

[b1gcountry]

There was a thread on AOW courses, where the topic of dive planning was discussed. I realize this has been discussed many times before, but I'm opening a new thread to move the discussion here...

Most dive instructors I know think gas management involves looking at your gauge every five minutes and aborting the dive at 500 psi. They honestly don't see any value in putting more effort into it than that ...

At the risk of going for seven years (LOL), Why do you suppose that is?

So at what point should divers be conducting more in-depth dive planning, and what should that planning be?

Please no comments on any of the training organizations, or classes being taught. I don't want to get into in which class this should be taught. I want someone interested in more advanced dives to get an idea of when they should be planning out more detailed dive plans.

Tom

 

[MXGratefulDiver]

Good topic, Tom ...

I believe it begins with the basics in OW, and goes more in-depth in AOW. OW should set the mindset and expectations ... and provide some basic rules of thumb. AOW should look more at the mechanics of "what can go wrong and how do we plan to deal with it".

The OW student has a lot on their plate, pretty much focusing their mental bandwidth on basic skills like buoyancy control and propulsion. Within the current training framework, there simply isn't time to go into detailed planning techniques. Nor is it particularly necessary for divers doing relatively simple, shallow dives.

The AOW student, on the other hand, is often taking the class for access to more aggressive dive profiles. By AOW, the student should be starting to get comfortable with basic skills ... and is ready to build on the foundation of what he or she was introduced to in OW. This is where we need to emphasize the importance of looking at your dives from the perspective of how much gas you NEED, rather than how much you'll end up with after it's over. This is where I really dig into the mechanics of gas consumption rates, and more importantly, emphasize that gas management is a fundamental part of pre-dive preparation.

This is also a great time ... since up till now most divers have been using rental tanks ... to show the student why, when they end up purchasing their own tanks, they may want to consider something bigger than an AL80 ... especially if they're going to be doing deeper dives.

Essentially, OW introduces you to skills, and gets you thinking in terms of doing things right.

AOW is a great place to add a layer of complexity to your planning and get you thinking about what to do when things go wrong.

... Bob (Grateful Diver)

 

[MikeFerrara]

There was a thread on AOW courses, where the topic of dive planning was discussed. I realize this has been discussed many times before, but I'm opening a new thread to move the discussion here...





So at what point should divers be conducting more in-depth dive planning, and what should that planning be?

Please no comments on any of the training organizations, or classes being taught. I don't want to get into in which class this should be taught. I want someone interested in more advanced dives to get an idea of when they should be planning out more detailed dive plans.

Tom

More in-depth than what?

I believe it begins with the basics in OW, and goes more in-depth in AOW. OW should set the mindset and expectations ... and provide some basic rules of thumb. AOW should look more at the mechanics of "what can go wrong and how do we plan to deal with it".

I mostly agree except that an entry level diver is being trained to dive so they need to know something of the mechanics of what can go wrong and how to deal with it. The same "theory" applies to gas management at the OW level.

The most basic case is a dive where you can surface anyplace. Each diver should reserve enough gas to conduct an ascent in the desired fashion while donating gas.

 

[jbd]

I agree with the comments by NWGratefulDiver but I also need to ask as Mike has done---More in depth than what??? What are we comparing to??? Are comparing the 40 foot reef diver to someone wanting to do a 165 foot dive with cave or wreck penetration???

FWIW gas management with an understanding of SAC rates should start in the OW course. By the time a person takes the AOW course they should have enough personal SAC rate info to plan and conduct dives based on that information during the AOW course. When a person takes a Master Scuba Diver course(NAUI) they should be able to say I want to do this dive(whatever its is) and work out how much gas it will take and what configuration of tanks they would need to do the dive they want. Maybe the standard AL80 will be enough. Maybe an AL80 plus a pony of some sort at 30 or 40 cf. Maybe the dive would require large doubles. The point is the person should be able, based on personal information, to determine what the correct gear is for the dive.

 

[TSandM]

I think the concept of "rock bottom" should be introduced in OW. The idea that you should always keep enough gas in your tank to get you and a buddy to the surface isn't that complicated, and some basic rule of thumb numbers could be provided to allow the new diver to know what he shouldn't go below in terms of pressure. It's not so much the math, as the way of THINKING.

By AOW, I think the concept of planning gas around the constraints of the dive should be mentioned. At this point, somebody may be thinking about doing some deeper dives, or some wreck dives off an anchored boat. Some of those dives (like the Spiegel Grove, for example) can get you into quite a bit of current, or very limited viz. For dives like that, being able to decide if you are dealing with an "all available air" dive, a "halves" dive, or a "thirds" dive, seems to me to be a useful set of concepts. In heavy current, being able to compare your actual gas consumption with your projected gas consumption can quickly allow you to revise your time estimates for your dive, so you don't get too far from the upline and have problems making it back. This would require that the diver have gotten a sense of his usual consumption rate at various depths.

Especially if you use "scuba math", this stuff isn't that hard to do. You can do it quickly during the dive plan, and you can check it underwater. I can even do it, and my thinking gets pretty muddled at 100 fsw. The problem isn't that it's too difficult. The problem is it isn't even discussed.

 

[Buoyant1]

I agree with the comments by NWGratefulDiver but I also need to ask as Mike has done---More in depth than what??? What are we comparing to??? Are comparing the 40 foot reef diver to someone wanting to do a 165 foot dive with cave or wreck penetration???

FWIW gas management with an understanding of SAC rates should start in the OW course. By the time a person takes the AOW course they should have enough personal SAC rate info to plan and conduct dives based on that information during the AOW course. When a person takes a Master Scuba Diver course(NAUI) they should be able to say I want to do this dive(whatever its is) and work out how much gas it will take and what configuration of tanks they would need to do the dive they want. Maybe the standard AL80 will be enough. Maybe an AL80 plus a pony of some sort at 30 or 40 cf. Maybe the dive would require large doubles. The point is the person should be able, based on personal information, to determine what the correct gear is for the dive.

Hmm...tough for new divers to worry about things like SAC since it would be WAY off the scale for them at first (until they settle in) Although teaching them how to calculate and use it would be something to teach from the beginning.

"Rock bottom" is also in that same picture

But teaching them how to evaluate the depth of their dive, and work out the tables for their absolute maximum bottom time should be something emphasized a bit more in the beginning.


By the same token, I think a lot of it has to do with the type of diving you are doing. If you are doing 20-50 ft dives on a boat with the charge "you have an hour, be back with at least 500psi" what's the point? I don't even need to do the math because I know that at those depth parameters with an 80 I can get 50-60 minutes (depending on current) and have enough gas left over to appease the DM. I just keep going until I either get tired, my buddy get's tired (or runs out of air) or the 60 minute go time.

Local diving it's with a 119, and usually ends when one of us get's tired, crampy, etc...

New divers shouldn't be doing dives where you need to calculate your time with a cylinder..but when you hit your AOW (or advanced dives for the sake of argument) you should be able to work out the basics for your needs for the dive. that should probably be a part of the required learning for AOW...at that point you should be a "responsible" diver!

 

[diverdowndh]

For me personally I started planning more when I got really comfortable with my equipment, etc. I am a self motivator and when I get into something I get into it 200% so every dive I make I try to improve or work on what I already have/know - the very reason I am also a DMC. For other divers? I would think it would be the point of the AOW class. That would be a pretty good indicator the diver wants to know and learn more.

 

[b1gcountry]

Refining my question a little...
What is the least amount of dive planning that you can teach a rank beginner in order for them to be capable of conducting a safe dive? You define the baseline here.

Building on this, What are the limits to your answer to the above question? What dive conditions would make the first approach dangerous?

Finally, what extra planning measures need to be taken once the above limits are reached?

 

[DIR-Atlanta]

What is the least amount of dive planning that you can teach a rank beginner in order for them to be capable of conducting a safe dive? You define the baseline here.

The Rule Thirds is pretty easy to teach, and is also very intuitive - one third of your gas to swim away from the entry point, one third to swim back, one third in reserve for you and your buddy. If you are back at the entry point with 1000+ PSI and feel comfortable using a couple hundred PSI just looking around before you surface, then that's fine too.

Other rules of thumb might include "start your ascent with no less than 600 PSI, or 100 PSI for each 10 feet of depth, whichever is greater". It's not as accurate as calculating Minimum Gas, but at least it gets the students thinking about reserve gas as a function of depth.

 

[diverdowndh]

Here is an idea - how about <gasp> checking with the tables on the depth/time that is given out on a predive briefing BEFORE diving? It is amazing to me how dependent other divers are on the DM - not that I've distrusted them, but knowing that it is ultimately my responsibiliy for my plan, I look just for reference. I would think more recently certified OW students would have their handy tables on the boat...