Deep6 Excursion - Repetitive Dives, Surface Intervals, Residual Nitrogen and Dive Planning

[tursiops]

I know anything else would be mad, but has anyone checked that this IS the ACTUAL behaviour of this particular computer?

Yes.

 

[dmaziuk]

There are many places where the SI will be less than an hour. It is good to be able to plan. There may be a significant difference between half an hour and 45 min

And then there are local lakes here with soft squishy bottom just around no-limit depth, where you leave your computer at home so the muck does not gunk up sensor openings. I agree that it's a feature that could be useful sometimes -- and it's trivial to program, except for the interface on 1- or 2-button devices with good old segmented LCD screens.

 

[lowwall]

For me, the biggest problem is that you do not know your stop time until you hit the stop depth. This is a very unusual way to handle deco.

I would assume this was a deliberate design choice to keep divers who had violated NDL from deciding "Hey, I've got more than enough gas for that long of a stop, I can stay here a bit longer."

The other possibility, and these are by no means mutually exclusive, is that the designers decided that users would mostly violate NDL through inattention. When the diver finally did get around to looking at the computer, the designers wanted to give a clear indication of how long the violation had been going on.

Perhaps this makes more sense if you consider the origin of this device as the Crest CR4. It was designed in Taiwan to serve the Asian casual diving market which "features" minimal training and guided dives with tight limits. Given this, the deco design choices are completely reasonable. BTW, this is why you get some odd displays such as fractional feet when you choose imperial units, it's built in metric and the imperial displays are straight conversions.

Deep 6 decided to make a branded version of the CR4 to serve the US recreational market because it fills a sizeable gap in current offerings. It's an inexpensive nitrox capable, watch-sized dive computer that uses a standard Buhlmann algorithm and has Bluetooth download capability.

Now, IMO, where Deep 6 could have done better is in customizing the software, both the device firmware and the logging app, and updating the manual for the US market. I know they were planning on doing this and I assume they are still working on it, but nothing has come out yet other than making downloads work (at least for some people) with the Crest logging app.

I can live with the design quirks given the price I paid (Deep 6 sold the first batch at a discount). However, I'm not so sure there aren't better options at the current price. At least until Deep 6 finishes its promised upgrades.

 

[scubadada]

I guess if you accept the fact that it is NOT a deco computer, and only provides the info you need to get you back safely if you should violate NDL, then everything is fine.
After all, that is how it is marketed.

OK, this is the only computer (Crest CR-4, Genesis Centauri, Deep 6 Excursion) that handles deco that way. All rec computers I know of give you stop time. This is also designed to get you to the surface safely. So, I still say, it handles deco in an unusual way.

 

[wetb4igetinthewater]

OK, this is the only computer (Crest CR -4, Genesis Centauri, Deep 6 Excursion) that hsndles deco that way. All rec computers I know of give you stop time. This is also designed to get you to the surface safely. So, I still say, it handles deco in an unusual way.

What would be your preferred way?

 

[tursiops]

OK, this is the only computer (Crest CR -4, Genesis Centauri, Deep 6 Excursion) that hsndles deco that way. All rec computers I know of give you stop time. This is also designed to get you to the surface safely. So, I still say, it handles deco in an unusual way.

I do not disagree. But I'm adding that I think that is not bad.

 

[lowwall]

This is going to border on philosophy, but... When I run into something that looks odd to me, I usually try to figure out why it's done that way. Working this out often helps me understand other details about the product/process/custom/culture I'm looking at.

In my experience, if you go through this process you will see that designers/people generally make rational choices given their initial assumptions.
Even where factors like laziness/short-sightedness/building to a price results in a sub-optimal solution, you can typically understand the thinking that led to this. The really big problems occur where those initial assumptions are flawed. People have an unfortunate tendency to accept just about anything as a bedrock principle if they are indoctrinated early enough or are caught at a vulnerable time. Once accepted, these principles are remarkably resistant to change, no matter how much evidence is provided to the contrary.

I'm talking about, umm, Ratio Deco of course. Or maybe Apple UI designers. Any resemblance to followers of certain religious, economic, or political practices is purely coincidental.

 

[dmaziuk]

What would be your preferred way?

"Principle of the least surprise". The problem is, one has to wonder what else they didn't know about software design when they wrote this computer's firmware.

 

[tursiops]

"Principle of the least surprise". The problem is, one has to wonder what else they didn't know about software design when they wrote this computer's firmware.

That "principle" sounds like a sure way to be a follower rather than a leader.

 

[wetb4igetinthewater]

"Principle of the least surprise". The problem is, one has to wonder what else they didn't know about software design when they wrote this computer's firmware.

That is, unfortunately, a common problem in the software industry. Some companies without the resources do an abysmal job. But keep your hopes up, there is always a chance that the firmware is upgraded to provide a much more intuitive interface