Shearwater coming out with new DC?

[dmaziuk]

I don't do any kind of serious underwater work--I just dive and look at the pretty fishes.

Have you ever looked away, looked back, and the pretty fish that was just there a moment ago was gone and took a while to find again -- if at all? I expect that is why you'd want the spg on your wrist in your field of view together with the camera, gun, or whatever.

 

[RonR]

Although you technically can use electromagnetic waves underwater, in practice it requires mile-long antennae. Or did last I looked. So I'm not sure what sort of RF they'd be using.

Oceanic and others use very low frequency RF. Data rates required are low, and the range is short, particularly in salt water. The required antennas are small and typically printed on the PCB. Liquivision, alone at this point, uses ultrasound, which can travel much further underwater, but has its own set of technical challenges they had to solve re. discriminating from background noise. This technology enables them to do direction finding and monitor buddies at a much greater distance.

-Ron

 

[Stoo]

SB has really changed over the last several years, many more dogmatic posters with questionable experience and expertise.

Like every other thing in the world... For every "offensive poster", there's at least three "offended" ones... ;-)

 

[clownfishsydney]

I am really amazed that so many people seem to think that you can blow off required decompression and then safely dive again the same day or the next day. There is a good reason why some computers lock you out if you do not do the required decompression. If you think you know better than the computer, then do not use the computer. By the way, my current computer (HW OSTC 2N) and my wife's (Predator) do not lock you out, but we certainly did not buy them for this feature.

 

[AJ]

There is a good reason why some computers lock you out if you do not do the required decompression. If you think you know better than the computer, then do not use the computer.

That's what I did. But I don't think I know better than my computer. Computers can fail and they do. That's why I trusted my Petrel instead of my Suunto when my D4i locked me out. Computers can and will fail. I am contemplating now buying a second Petrel or Perdix because I trust Shearwater.

My point is: keep thinking for yourself what is the truth. Don't rely ever solely on what a computer is telling you. Not even if it is a Shearwater.

 

[uncfnp]

I am really amazed that so many people seem to think that you can blow off required decompression and then safely dive again the same day or the next day. There is a good reason why some computers lock you out if you do not do the required decompression. If you think you know better than the computer, then do not use the computer. By the way, my current computer (HW OSTC 2N) and my wife's (Predator) do not lock you out, but we certainly did not buy them for this feature.

Who said that it was ok to "blow off required decompression"? Some said there was a mistake in setting the decompression settings on a backup computer, diving two computers, and the diver elected to continue diving the primary computer. You believe this is dangerous?

Others have noted that many recreational computers have a lockout feature not present on the Shearwaters or as you noted the HW OSTC 2N. Why is that? Why do some manufactures assume there is a thinking diver attached to the dive computer and others do not? Is it a rec vs tech feature?

Do I think I know better then my computer? Sometimes. I think I am in control of my dive and that the dive computer is one, admittedly important, component of my dive plan. Do you blindly follow your dive computer?

 

[Sevenrider860]

Suunto computers lock the algorithm and go into gauge mode when you skip a stop for more than three minutes. They then keep the algorithm locked for 48 hours. The Atomic Aquatics Cobalt goes into a DECO Violation mode but still displays a stop schedule with the caveat that it may not be valid. It then locks the decompression algorithm for 24 hours. The Hollis DG03 goes into a variation of violation modes depending on the condition and will do it's best to provide a stop schedule as long as the stops are 60Ft or shollower. Any of the DG03 violation modes will require a 24 hour surface interval.


These are all generally considered recreational computers. They all have a section in the manual that talks about omitted decompression stops and the impact of violating the schedule. The Cobalt and DG03 at least try to give the diver a plan to the surface after a deco violation, the Suunto just gives you the big middle finger after 3 minutes and says your on your own. I personaly am not too concerned with an algorithm lockout on a recreational computer, although I think 48 hours is excessive. If the violation occured on a backup computer because a mistake was made in the settings, it now no longer matches the primary computer as far as tissue saturation calculations are is concerned anyway.


The user manuals for my two technical oriented computers (Liquivision XEO and Shearwater Petrel) do not have a section about omitted decompression at all. That topic is not even a point for discussion. The manual for Recreational mode on the Petrel has a small section that says there is no lockout, just a clear indication that the schedule was violated...you may want to seek help.


There IS a distinction between technical oriented computers and recreational computers because there are a lot a "non-thinking" divers out there. These divers likely need a piece of gear that says "Hey dummy, after that last dive you need to sit it out in the penalty box for a while." The technical oriented computers continue to run the algorithm because the targeted users should know it is just a mathematical algorithm anyway, and if they omit a required stop or stops they are dealing with it topside or will certainly factor what occured into their future dive planning.


For me personally, I never want a computer to lock me out on a technical dive, simply recalculate, recalculate, and recalculate as I ascend. There is likely a reason I blew through that stop. For a recreational dive and a recreational dive computer, I really don't care if the computer locks the decompression algorithm after a violation. It is easy to dive the computer's profile to avoid violations. If it locked because of my mistake, like I set a mix wrong (air instead of 36%), and chose to ignore the stop, then it is not calculating my tissue saturation correctly anyhow and it was my decision to violate the schedule.

I like the Shearwater way of handling deco violations for MY diving. I really like the idea of an algorithm lockout for other divers I have been exposed to over the years.

--- RonR clarified the behavior of the Cobalt in this thread. It does not lock the algorithm, it just keeps the violation visible for 24 hours. The computer can be dived again with this warning and it the algorithm will continue to operate. Thank you Ron!

 

[lowviz]

...//... There IS a distinction between technical oriented computers and recreational computers because there are a lot a "non-thinking" divers out there. These divers likely need a piece of gear that says "Hey dummy, after that last dive you need to sit it out in the penalty box for a while."

Agreed.

...//... For me personally, I never want a computer to lock me out on a technical dive, simply recalculate, recalculate, and recalculate as I ascend. There is likely a reason I blew through that stop.

But that can only happen on a technical dive?

...//... I like the Shearwater way of handling deco violations for MY diving.

...//... I really like the idea of an algorithm lockout for other divers I have been exposed to over the years.

There is my issue with what you posted.

Those divers would be on the lower side of the Bell curve and (for them) I would agree with everything that you have posted.

However, a Shearwater recreational offering would most assuredly be aimed at the other side of the same Bell curve. Nothing would be broken by such an offering. Right now, today, you can’t stop anyone from buying too much dive computer.

I support freedom of choice in what is available for me to purchase and stiff competition to keep everyone honest while providing a rich set of choices. I still see a lack of a good DC for the "tech minded" solid recreational-only diver. The best option today is to buy a tech DC and dive it rec. I’ve been won over in this thread when it comes to AI. I doubt that I would use it, but why deny others a choice that many intelligent recreational divers seem to really want? And why not lighten up on the nanny whining and complaining coming from your wrist for this same group of divers?

A lock-out is fine, just move it over a few notches so that it agrees with what you know to be true in the tech world.

 

[Lorenzoid]

I would have no objection if Shearwater could incorporate wireless AI without increasing the price of the computer and could guarantee that a diver who doesn't want AI can set the computer to a mode in which AI is invisible. Oh yeah, and guarantee that the AI feature is so walled off from the rest of the computer that it cannot adversely affect any other function.

 

[RonR]

<snip> The Atomic Aquatics Cobalt goes into a DECO Violation mode but still displays a stop schedule with the caveat that it may not be valid. It then locks the decompression algorithm for 24 hours. <snip>

Just to clarify how the Cobalt handles missed deco stops:

• We display a big yellow banner saying that there has been missed deco, the schedule might not be valid, but attempt to recalculate a best path to the surface.
• That warning will continue to display for 24 hours, and there is a warning screen whenever you enter dive mode for the next 24 hours.
• We don&#8217;t lock out the algorithm, and we allow the diver to decide if the violation was a relatively trivial one or something that should be taken seriously. Continued diving is allowed with the warning, and the algorithm continues to operate. So if the Cobalt were being used for a backup, and were more conservative than your primary, you could follow the other computer without any kind of lock out. Apart from the warning screen and banner, the Cobalt continues to function normally on subsequent dives.
• We don&#8217;t use a fixed time limit to determine what constitutes a missed stop, but an algorithm that takes into account the stop depth, time away from the stop, distance away from the stop, and the overall schedule.

Stop depths are somewhat arbitrary, and as a for-instance missing part of a short 80 ft stop might just result in recalculating a schedule that had a little more time at the 60 ft stop. You will still get a warning, but the Cobalt continues to calculate. In an extreme instance the algorithm might not be able to provide a stop that is shallower than your current depth, and will want to send you back down. Probably in that scenario there are some bigger problems, like being out of gas or having an equipment malfunction that are driving the situation.


Essentially we warn, but leave the decision up to the diver.

-Ron