I want to murder my computer and feed it to the fishies!

[ianr33]

Hi Dubois,
Seems I owe you and your computer an apology. It,and the planning software, obviously has the capability to plan a complex dive in advance. Guess you learn something every day!

I usually plan with GF 30/85 and sanity check the results with VPM+2 (Computer is set to 30/85) so the numbers are very close to your example with GF30/80

The important point here (that we obviously agree on) is a diver needs to be able to predict what his computer is going to do on a dive before he gets into the water.
Cheers!

 

[Hatul]

This is exactly the point they are trying to get across to you. If you don't understand the differences in what the computers are telling you, and why, then you probably need to learn more about deco theory. The best way to do that is with an instructor or a mentor who is well versed in it. Learning from some random guy on the internet is not the way to do it, because you don't have any way to assess if they know any more about it than you do.

While the same may hold true in person as well, at least you are able to make a more personal assessment of them.

Sorry but I found your post patronizing and condescending and does not address the questions.

Adam

 

[Hatul]

Don't know about your Mares computer, but if it has a simulator mode you can do deep deco dives in the comfort of your desk. I do that sometimes with my Suunto Vyper. If it has that mode it's very useful because you can check out exactly what's happening with the deep stops, and how the deco time can increase with a slow ascent, and perhaps solve the puzzle of the increasing deco time at 10 feet.

In Suunto parlance there is a depth called the floor. Below the floor the tissues absorb nitrogen and increase the decompression obligation. Above the floor the decompression starts. If you spend more time below the floor your decompression obligation will increase and this would explain your increasing deco time. My Vyper informs me that I'm below the floor with an upward arrow and blinking total ascent time. Above the floor the arrow disappears and the total ascent time no longer blinks. Perhaps the Mares has similar functions.

The question of whether missing the deep stop increases your deco time can also be answered with the simulator if it has one.

Adam

 

[iztok]

Sorry but I found your post patronizing and condescending and does not address the questions.

t
Actually it is neither. It tells the OP to get a good knowledgeable instructor and/or mentor. It was clear that OP doesn't understand the basics. You now, the theoretical tissues, their M values, etc.

Sure trial and error is great way to build a complex system and complex set of knowledge, however the critical problem is that not only mistakes have to be made, it is very hard to make the good mistakes. If one doesn't understand why slow ascent might prolong the decompression time instead of shortening it the simulator method will not explain that it will just tell you the same thing what was observed. It will not tell you that perhaps a slower tissue compartment might now became a controlling compartment and thus drastically increased the deco obligation.

Sure the question of missed deep stop increasing deco time can be answered with the simulator. It will tell you if time got increased or not, but it will not be able to explain why it happened. This is where good instructor/mentor and books will come in. Your advice to the OP is basically teaching one "what to think" and not encouraging one "how to think". Sure "tides go in, tides go out" is a good observation point but it is important to understand why it is so and by observing tide simulation one doesn't get that info.

 

[kotik]

Actually it is neither. It tells the OP to get a good knowledgeable instructor and/or mentor. It was clear that OP doesn't understand the basics. You now, the theoretical tissues, their M values, etc.

Agreed.

Iztok,

You said earlier that her plan to "dive until we had 20 minutes of decompression and then surface" wasn't a plan. I will respectfully disagree with that-- it's sort-of a plan, very similar to "dive until we have 700 psi and then surface". It's a recreational style plan applied to an overhead environment, the sort of planning that goes into the great majority of dives that we read about in little newspaper articles from time to time.

Hatul,

Knowing how to play with your computer at the comfort of your desk doesn't prepare someone to safely dive in an overhead.

The original poster exposed quite a few gaps in basic knowledge of the hazards of the environment she's entering. It would be irresponsible to recognize this and then respond saying nothing about it, but pretend instead that all she needs to know can be found in a paragraph in the computer's manual. Cave Diver and the others have no duty to just play along-- in fact I would say there is actually a duty to speak out against her foolishness, for the sake of people who read the thread as well as Melanie's. To simply answer her question while ignoring the glaring issue lends validity to what she's doing. To do it publicly where someone impressionable might follow the same broken thinking is bad citizenship in my opinion.

You aren't an instructor, Adam, technical or otherwise, or you wouldn't be giving Melanie or anyone else encouragement to do this sort of diving with complete disregard for the training required. You should not present your advice on how to do what she's asking without the qualification to do so.

--Eric

 

[Slamfire]

Don't know about your Mares computer, but if it has a simulator mode you can do deep deco dives in the comfort of your desk.

I don't have the M1 desktop software but I have Puck's desktop software. Pucks are a more recent model than the discontinued M1. I have to say that the Puck desktop software is not very strong at all. It's cumbersome, buggy, and you don't get basic easy information like the average depth for a dive. I almost always end up exporting the depth readings to Excel and analyzing dives in Excel. Hence the reason for me asking Dubois if he's made any progress reverse engineering an interface software.

Puck software does have a simulator mode, but it has very poor usability. In my opinion it's so poor that it's just not worth using it. In order to use it you have to start with an existing dive in your log and set that dive to "Simulator Mode". This will allow you to move any depth reading point up or down the water column. I don't think you can add or delete data points, therefore you are stuck with the same overall runtime as the original existing dive you started with. The other problem is that you have to move all data points in an existing dive in order to conform to the profile you want to simulate. In a short 45 mins dive that means moving 135 data points. Deco dives tend to be longer and a 80 min dive is almost 250 points. I just don't have time, inclination or patience to be clicking and moving data points 250 times. It just so much easier to run a profile through MV-Plan or V-planner. And finally, if you hit save after you made your modifications in the simulator mode, I think you'll overwrite your existing real dive and lose it.

In short, for me that simulator mode is useless.

 

[Tortuga68]

You aren't an instructor, Adam, technical or otherwise, or you wouldn't be giving Melanie or anyone else encouragement to do this sort of diving with complete disregard for the training required. You should not present your advice on how to do what she's asking without the qualification to do so

The number of posts on scubaboard in particular and the internet in general would drop dramatically if everyone heeded that advice. Which could either be a good thing or a bad thing depending on how you look at it

 

[Hatul]

If the M1 has no simulator function DiveNav has PC dive simulators for various computers and even if there is not one for the M1 I bet all the Mares use similar or the same algorithm, so you could just try one of the simulators close to the M1.

As far as the wisdom of the dive, she did not ask for advice about it and many of those that criticized provided no attempt at answering her question. It's fine to offer advice after answering her questions, but harping about it over and over is a bit too much and is likely not to be productive.

Adam

 

[melanie.]

Thanks Adam

I looked into the simulator mode on my computer some more. (It doesn't work on desktop software). I was able to simulate a deco dive. Couple things I found

Skipping a deep stop does not increase deco obligation (That is if it is even allowing me to skip it, pressing the button to ascend as quickly as possible but how long it was at the depth is hard to figure out)

There is no warning on upcoming deep stops

Deco obligation still adds up even while ascending until it reaches approx 50 feet. - Yes even if it is done faster then 33ft/min. (ie the little bar on the side comes on, too many bars and it is uncontrolled ascent). Also, scanning the profile of the actual dive in question, it looks like I wasn't going extremely slow. The first bar showed on approx every second point so to me that seems that on average I was going up right around the rate it wanted, so as to not show a fast ascent. Interesting since using V-planner for the same depth, it shows that offgassing starts at approx 90 feet.


If it goes to a stop at 20 feet, I can no longer see how much I will have to do after at 10 feet. However I am able to see how many minutes it has planned to ascend so a little simple math and I get the gist of it.

Deco at 10 feet still does not count down reliably. Ie 12 minutes to clear 10, 25 mins to clear 22. No matter what profile I fooled with it always took longer. Considering that time cleared almost as well at 20 feet why am I trying so hard to be at 10?

Knowing how to play with your computer at the comfort of your desk doesn't prepare someone to safely dive in an overhead.

You are right. But the things with overhead is that it really is simple. If I do it wrong I can kill or seriously injure myself.

Every single one of my dives here have an overhead environment. The purpose of the dive in question was to explore what my computer does in real world situations.


Thanks for all the help

 

[Garth]

My story with mares puck rgbm is about someone I didn't know and who I wasn't diving with. I dove the oriskany with a planned run time of 84 minutes. I got out of the water after staying an extra 2 minutes at 20ft making my dive 86 minutes.
The recreational diver using your computer went a little deep and ended up with 30 minutes of deco on his second dive with the same situation you talk about, only when he turned the dive he had 8 minutes of deco. By the time he went through half of it he would have died because he exhausted his aluminum 80. The divemaster was nice enough to share his sling bottle (al 40) which saved his life by 20 minutes. How did this happen? Well the captain was pissed.. I wasn't impressed by the diver but was thankful for the DM.