Deco plan nothing matches. VR3? V-Planner? Tables?

[carlthecat]

Here is my problem. I am doing some dive planning and when I try to plan a dive to 150 feet for 25 minutes on air I get a bunch of different plans. For example, here is the dive plan for tables, V-Planner, and VR3 with different configurations.

IANTD / US Navy Air Decompression Tables (C-3302B)
20 feet – 7 minutes
10 feet – 20 minutes

IANTD / Bühlmann Air NDL & Deco w/Optional 75% Accelerated Deco (C3501)
40 feet – 3 minutes
30 feet – 4 minutes
20 feet – 4 minutes
10 feet – 22 minutes

V-Planner (safety = 0 or nominal) VPM-B or VPM-B/E
80 feet – 40 seconds
70 feet – 2 minutes
60 feet – 2 minute
50 feet – 3 minutes
40 feet – 5 minutes
30 feet – 7 minutes
20 feet – 10 minutes
10 feet – 19 minutes

V-Planner (safety = 1) VPM-B or VPM-B/E
80 feet – 40 seconds
70 feet – 2 minutes
60 feet – 3 minute
50 feet – 3 minutes
40 feet – 5 minutes
30 feet – 8 minutes
20 feet – 11 minutes
10 feet – 21 minutes

V-Planner (safety = 2) VPM-B or VPM-B/E
80 feet – 40 seconds
70 feet – 2 minutes
60 feet – 3 minute
50 feet – 4 minutes
40 feet – 5 minutes
30 feet – 8 minutes
20 feet – 13 minutes
10 feet – 22 minutes

VR-3 (with safety = 0)
95 feet – 2 minutes
68 feet – 2 minutes
40 feet – 1 minute
30 feet – 4 minutes
20 feet – 10 minutes
10 feet – 28 minutes

VR-3 (with safety = 1)
95 feet – 2 minutes
67 feet – 2 minutes
40 feet – 1 minute
30 feet – 6 minutes
20 feet – 12 minutes
10 feet – 32 minutes

VR-3 (with safety = 2)
100 feet – 2 minutes
75 feet – 2 minutes
50 feet – 1 minute
40 feet – 1 minute
30 feet – 7 minutes
20 feet – 15 minutes
10 feet – 35 minutes

Obviously, I will follow my dive computer first, but what happens if my dive computer fails in the middle of a deco-plan? I may or may not remember what the deco schedule was. Sure I could write it down right before I start the deco, but I would like something easier. So, to get to the top without getting bent, I turn to the tables or a printout from V-Planner and it doesn’t match the VR3 algorithm. So I will have to wing-it and do the best to add the necessary conservatism to get to the surface safe. If the computer fails before the deco-plan and I stayed within the bounds of the dive, then I can just follow the tables without problem. I know all these planners use different algorithms, but since they are all adjustable, how can I get something close to the VR3? Any ideas?

I just want stuff to match. I would love something to match the VR3. I don’t want to buy the VR3 dive planning software because I am fond of V-Planner. I also don’t want to upgrade the VR3 to the V1 Upgrade (VPM-B/E) model yet. Is there anyway to get some more agreeable deco plans without either of the 2 previous solutions?

Right now, I would follow the micro-bubble stops on the VR3 and then if there are problems with the computer I would follow the Bühlmann tables (second in the list).

Any help on getting these different planning tools to agree will be greatly appreciated.

Thanks to all who reply in kind.

Carl the Cat

 

[Rick Murchison]

Pick a Plan.
Use it.
Personally I like VPlanner, but nothing will guarantee your safety.
Rick

 

[rjack321]

Contingency planning should have been covered in your deco class. You have had one right?

 

[ScubaMilo]

Do you really want to follow that computer generated plan blindly?
When you took your deco training they should have covered dive planing.
In the event that this was not covered, You may want to find another instructor.
Deco tables and computer programs are someone's interpretation of different deco theory's!
Therefore they will vary.
Remembering your deco plan should not be that much to ask.
Good Luck to you.

 

[carlthecat]

Yes. I have had a deco class. But contingency plans cover when you go past the parameters of the original dive plan, not when the computer malfunctions and you are left following a different deco plan than the computer presented.

My contingency is the deco plan for a dive that is target depth + 20 feet and target time + 10 minutes.

Also, dive planning was covered in my classes and I understand it fully, however I still want my dive computer and any other deco planning source to match. Another reason for wanting something to match my dive computer, that I didnt mention before but should have, is to verify the deco plan. If the computer says "this" and my table or V-planner says "that" and "this" is exactly or pretty close to "that" then the deco schedule is verified since the chances for both to be off and agree is very, very low. This would address ScubaMilo's concerns about following the computer blindly.

It seems I am going to just have to say F-it and either make tables using the VR3 or spend the money to upgrade to the V1 -VPM-B/E algorithm so it will match (or at least resemble) V-Planner.

If anyone else has anthing to add, please feel free.

Thanks for your responses.

Carl the Cat

 

[mattroz]

why don't you sell that expensive computer and buy a bottom timer. then make your plan on V-planner and follow your plan?

what am i missing here?

 

[wedivebc]

Do you really want to follow that computer generated plan blindly?
When you took your deco training they should have covered dive planing.
In the event that this was not covered, You may want to find another instructor.
Deco tables and computer programs are someone's interpretation of different deco theory's!
Therefore they will vary.
Remembering your deco plan should not be that much to ask.
Good Luck to you.

You know people take courses and then after a while they don't use the information they need a little help with a certain point. I really get tired of this "get a new instructor" mentality when someone forgets or missed a key point of training. Why don't people take responsability for their training. It is the instructor's responsabilty to teach. It is the individuals responsability to learn.

 

[wedivebc]

Yes. I have had a deco class. But contingency plans cover when you go past the parameters of the original dive plan, not when the computer malfunctions and you are left following a different deco plan than the computer presented.

My contingency is the deco plan for a dive that is target depth + 20 feet and target time + 10 minutes.

Also, dive planning was covered in my classes and I understand it fully, however I still want my dive computer and any other deco planning source to match. Another reason for wanting something to match my dive computer, that I didnt mention before but should have, is to verify the deco plan. If the computer says "this" and my table or V-planner says "that" and "this" is exactly or pretty close to "that" then the deco schedule is verified since the chances for both to be off and agree is very, very low. This would address ScubaMilo's concerns about following the computer blindly.

It seems I am going to just have to say F-it and either make tables using the VR3 or spend the money to upgrade to the V1 -VPM-B/E algorithm so it will match (or at least resemble) V-Planner.

If anyone else has anthing to add, please feel free.

Thanks for your responses.

Carl the Cat

One other option would be to use the Buhlmann version of GAP. It is a free download and uses gradient factor which you can tweak to match your VR3.

BTW: I cover lost tables/computer contingencies in my tech training. Excess depth/ run time should not happen if you are paying attention.

 

[carlthecat]

Thanks Dave. You gave me a feasible option and I appreciate it. I am going to take a look at GAP. Uncle Rick was helpful as well.

It is hard to believe that posting a question regarding trying to get the VR3 and a table or output from a dive planning software suite to match would make me suspect and generate questions of doubt. I am 100% confident in my abilities to plan dives. I already have a plan for getting to the surface if the computer goes down at any point of the dive. Furthermore, I am 100% sure I can safely ascend if my computer broke, my wrist slate fell off, and a fish ate my dive tables. Maybe I wasn’t completely clear on my intentions regarding this thread. When I wrote:

Obviously, I will follow my dive computer first, but what happens if my dive computer fails in the middle of a deco-plan?

That sounds like a question that will make people doubt I know what I am talking about. But if you look at it in its entirety the question is part of a narration:

Obviously, I will follow my dive computer first, but what happens if my dive computer fails in the middle of a deco-plan? I may or may not remember what the deco schedule was. Sure I could write it down right before I start the deco, but I would like something easier. So, to get to the top without getting bent, I turn to the tables or a printout from V-Planner and it doesn’t match the VR3 algorithm. So I will have to wing-it and do the best to add the necessary conservatism to get to the surface safe.

I guess the word “wing-it” doesn’t sound confident and may add to the skepticism. Maybe I should have written “adjust the deco” in lieu of “wing-it”. Anyway I look at it, I wasn’t being clear to everyone.

The original theme of this thread was to see if anyone came up with a way to make the VR3 match backup dive tables or the output from dive planning software. A simple question that required a “yes, do this…” or a “not that I am aware of” response. I wanted to know if someone had an answer so I could start my verification / research there instead of starting from scratch. Anyway, I will start experimenting and when I am done, I will post the results on how close I can get a backup source to match the VR3 for any that are interested.

Thanks for your responses.

 

[grazie42]

cant you simulate your "planned dive" on the VR3 and just write the stops on your slate? (I´ve never used one so forgive my ignorance)...if all you want is the schedule that the comp provides?

you´ve stated that you "dive your plan" so it sounds as if its doable...