Mares M1 RGBM

[leadweight]

Roak, I'm doing the deep stops now, just not getting credit for them. I think they had their origin with pearl divers or something like that. They felt better after the dive. Frankly, diving always makes me feel better.

What I suspect, after reading a thread about RGBM conservatism in Dr. Deco and other things, is that Suunto started with very short no-stop times and then further reduced them for short surface intervals and multi-day diving, possibly reverse profiles, but mainly through a series of reductions in the M-values.

I usually ease up on my Aladin when remaining no-stop gets down to 5 minutes or even a bit more. With the M1 it is likely that I will not back off so much becuse it is taking into account some of th ethings that the Aladin did not, thus reducing the need to outguess the meter.

That said, I have found that the menu system is easy to use, the buttons havea positive action (at least on land) and many of the Icons are too small to see without reading glasses. Fortunately, the layout of the display changes enough from mode to mode so that I can tell where I am without being able to read the icons.

One of the reasons I chose the M1 is their use of cheap and universally obtainable AAA bateries. Mares also made the battery change operation very easy, about as much effort as replacing the cells in the average dive light. The thing even comes with the batteries out.

Some of you have PM'ed me about where I bought it. Rather than give them a free plug, I will just say that it came from the best known and most obvious source of low price mail order dive gear.

 

[Genesis]

Be aware that one report I have on this "RGBM" computer is that it only will post the deep stops when you have ~5min of NST left or less - and not otherwise.

I, personally, prefer a "deco-style" ascent profile even when diving within the no-stop times.

I believe that all dives should be conducted this way - since I see very little reason not to. If gas supply is an issue for this then you need to be addressing your consumption anyway, because if you run that close to the "empty" mark you've got bigger things to worry about (like truly going OOA)

The whole "be back on the boat with 500psi left" thing is hogwash. You don't get credit for your 750psi in the tank when you reboard (well, I do, since I remix in my garage, but most people don't!) so why not use it to reduce your risk of a hit even further?

It will be interesting to see what kind of profiles the computer wants you to dive once you've actually used it... I will be looking for a real "in use" report!

 

[Charlie99]

Be aware that one report I have on this "RGBM" computer is that it only will post the deep stops when you have ~5min of NST left or less - and not otherwise.

It is hard to have a nice user interface that indicates recommended deep stops before they are truly required. IIRC some Uwatec computers try to do something like this with "level stops" for microbubble suppression, but most divers turn off the feature because it is just too confusing to use.

What I'd like is some way for me to tell the computer "I want to take xx minutes to ascend", and then have it distribute the time between deep stops and final hang in an optimum manner. I do this mentally myself, but being lazy, I'd prefer the computer to keep track of the time for me. When I do my mental guesses correctly, my Oceanic will just be going into the green (leading tissue about 85% of M value) when I start ascent from safety stop.

 

[Genesis]

Yeah, I think that's pretty much the deal Charlie....

But why not have a "recommended" ascent profile, but one that doesn't "violate" you if you ignore it?

For example, I do a 100' dive for 15 minutes on air. I'm near the NDL, but not over on my Suunto Vytec. As I begin my ascent, it could "recommend" a stop at 70' for 1 minute, then 1 minute for every 10' until 30', 2 minutes there, then the "safety stop" between 19 - 10', where it would show the recommended 3 minutes.

Now if I blow off the "recommended" stops, I may pay a penalty in repetitive dive times, but I do not "bend" the computer, as they are "recommended" stops rather than "required" stops.

I fail to see why this is difficult to program into the computer's logic...... or why it would be confusing.

Basically, the computer could offer me a "deco-like" profile for ascent that I could follow for best microbubble suppression and repetitive dive credit, or I could blow off those "recommendations" if I decided to and dive a traditional "M-value" type of profile.

I don't find the argument for a "true" RGBM implementation very compelling absent something like this. Indeed, folding something like VPlanner into a dive computer could provide this kind of thing too.

 

[leadweight]

Genesis, I believe you are correct about a deep stop being required only when the dive gets close to the no-stop limit. It might have even been that BRW sid something about it in Dr. Deco. However, no-stop limits (especially on air) are so short on contemporary computers at 100 to 120 feet that most dives to that depth will go below 5 minutes no-stop time.

Charlie, as far as the interface is concerned, the manual indicates that the deep stop signal covers the no-stop time remaining area. However, the manual also states "when th ediver approaches the deep stop depth, M1 sounds an audible alarm and displays the message "St 1min". I will find out if this means that the no-stop time is not obscured until the ascent is partially complete and the diver is about to make the stop, or as with the Aladin Smart series the level stop cuts in at depth leaving the diver without any indication of his remaining mandatory no-stop time prior to the ascent.

As an aside, I think the Smart series is definitely a not-for-me product. Rather expensive, has the weird level stop behavior, very difficult to operate out of the water, and requires a PC hookup to change essential settings. No wonder they only sold 6000 of them as of when the recall started. If Uwatec does not modernize their line with the features that people want, they will remain a niche player, amazing since they once had 85% of the market.

 

[Jai Bar]

FYI
what you describe is not a true RGBM computer. It is a modification of a 10 compartment (neo-haldanian model). RGBM models do not contain any "tissue compartments" or M-values.

 

[Genesis]

FYI
what you describe is not a true RGBM computer. It is a modification of a 10 compartment (neo-haldanian model). RGBM models do not contain any "tissue compartments" or M-values.

BRW claims otherwise.

I wish the marketing-speak would get put the f@#$ away on this stuff and we could get some straight talk from the manufacturers.

 

[DivesWithTurtles]

FYI
what you describe is not a true RGBM computer. It is a modification of a 10 compartment (neo-haldanian model). RGBM models do not contain any "tissue compartments" or M-values.

For reference: http://www.scubaboard.com/showpost.php?p=456714&postcount=19

-=[Gabe]=-

 

[Genesis]

That's still pretty fuzzy, and does not actually answer the question.

 

[Jai Bar]

I have read before Bruce's post on this board. It is fuzzy, but actually says that they (Suunto, and apparently Mares too) took a "neo-haldanian" model and modified it with some factors that change the Mvalues in order to approximate to RGBM.
There are some computers on the market that are real RGBM (instead of "Tissue Compartments" with half times they use surface tension of buble, ambient pressure, pressure inside bubble etc.)