Use a Computer or BT?

[packrat12]

I guess I will wade into this pool. When I was reading that line in my manual on the Shearwater, I lMAO. Went to my wife and child, they also L<Their>AO. I LOVE my Petrel and prefer it over any other computer I have used or seen. At $1,800, what I expect is a good product. I have NEVER seen a bug-free product at any cost. My Petrel costed nowhere near $1,800 either. It is a niche product used by tech divers and some rec divers. There probably are no more than 5 computers made for serious tech diving to choose from. It is very well made product and has a great reputation which should last a long time. As a tech diver, a DC will always be used in redundancy with another method to surface, e.g. timer/computer etc.. If it boggles you that they would announce that, then you probably would not be ready for tech diving anyway. Shearwater probably has one of the finest customer support reputations in the business. I saw this on a cave country t-shirt which says it all: Tek Diving (Noun): The art of Vague Assumption; Based on Debatable Figures From Quasi-Reliable Instrumentation; Performed with Equipment of Problematical Accuracy; By Persons of Doubtful Reliability and Questionable Mentality.

 

[Lorenzoid]

We can disagree, then. In my view, $1800 (and that's an exaggeration of the price by a factor of two) is still a consumer-grade product. Maybe if I were to buy a $20,000 aerospace-grade computer I would expect the likelihood of a bug to be infinitesimally small. I don't see "too many competing products out there"--I see products from manufacturers who apparently haven't given the issue of their disclaimer, potential bugs, and perhaps other issues, as much thought as Shearwater. I suppose the fact that I'm a lawyer and former computer engineer has something to do with why I'm enamored with their candor. Yeah, I'm biased. Anyway, this was an interesting side-topic. I suspect we will never know what Shearwater's thinking was.

 

[Nasser]

When Neil Armstrong and Buzz Aldrin where getting ready to land on the moon... during the last few minutes of their descent they encountered a bug in their computer navigation system. There where alarms going off everywhere and the system was so overloaded that it could not process all the information. As a result, the computer was guiding them straight to a large crater filled with boulders the size of trucks. Armstrong disengaged the system and manually guided the lunar module to a safer area where they safely landed with only a few seconds of fuel remaining.

This was with a computer that was state-of -the art for it's time, cost millions of dollars, and was designed by some of the greatest engineering and scientific minds of that era. Sure by todays standards a pocket calculator is more powerful than what they had, but it was ultimately Armstrong and Aldrin's technical training and experience that averted almost certain disaster. I think if they had put complete faith in their computer system and expected it to be completely "bug free" without the option to manually override the system then they would probably not have been ready to make that historical voyage... let alone succeed.

Just a thought.

 

[EFX]

its a Canadian thing..... humor them or they might stop sending us good beer.....

I should have known better. They expected me to drink the beer before reading the disclaimer.

---------- Post added June 11th, 2014 at 08:31 PM ----------

Well, we've had some fun with the disclaimer -- no? Since threads can often take a life of their own I want to post a disclaimer of my own.

First, to Shearwater. I meant no malice to the Petra product or implied that it was in any way deficient in its capabilities. My "shctich" was only with the language of the disclaimer itself. In regards to bugs I prefer to see their acknowledgment as an exception rather than a rule. I would have no hesitation to plunk down $100 in cold hard cash to bet that you did everything reasonably possible to ferret out and correct bugs. I would consider purchasing your product.

To my loyal respondants. I completely agree that backups are required. This is irrelevant to the language of the disclaimer. The use of a backup, as a mitigation to buggy software, does not excuse Shearwater of eliminating all such bugs. Finally, I have a brain (at least when I'm not drinking Canadian beer) and realize that the disclaimer is not an admission of negligence, but the possibility of bugs due to the sheer complexity and nature of software development as others have posted. Despite what you infer from the disclaimer read the rest of the manual. It is well written and informative.

 

[Dr. Lecter]

My issue is not with the disclaimer; Of course they need a disclaimer we live in a litagacious society. But there is a difference between saying there is a bug and there might be a bug. Shearwater's rank candor is simply not necessary. The implication is one of neglect. It's also conceivable that the software is bug free however improbale that may be so why eliminate that possiblity. How 'bout rewriting it like this:

"This computer may have bugs. Although we prerform exhaustive tests in and out of the water to remove bugs in the software,
it is possible certain bugs may remain. Please report any issues you have and we will do our best to fix them."

Except based on everything we (and more importantly, SW) knows about dive computers, "may have" is false. SW doesn't do marketing, or overly legalistic warnings - they do upfront disclosure of the limits of their gear, written in plain language. The implication of neglect would require a real possibility of eliminating all bugs through ordinary (or even extra-ordinary) diligence. That possibility, realistically speaking, is zero.

The bull legal version of the disclaimer would have "may have" in deference to Marketing and hinging on the fact that it's humanly impossible to say for absolute certain that this isn't the first DC created without even a single bug.

The use of a backup, as a mitigation to buggy software, does not excuse Shearwater of eliminating all such bugs.

Now it's time for you to call Legal. Nobody, even SW, has an obligation to eliminate all bugs -- they have an obligation to exercise ordinary care in finding and eliminating bugs. While what's a reasonble level of diligence in building a technical DC is likely quite high, it's nowhere near requiring them to do what you suggest is "not excuse[d]." Which is good, because that's an impossible standard. Hence the language.

 

[kr2y5]

I always find it curious how many people print such limited tables for their diving. 2 contingency tables is quite a small range of potential eventualities (deeper, shallower, shorter, longer, varying degrees of each of those variables). Also curious is that it appears that people re-do this process over and over.

How many tables do you carry for a typical dive, and how many possible dive profiles / deco schedules do they cover?

 

[PfcAJ]

Last week I did a dive planned for an hour at 170. I brought laminated tables for 160-210 with bottom times ranging from 30mins to 90mins.

So one side will have "160" with stop times for 30min, 40min, etc. The other sides has 170'. Then another laminated sheet has 180 and 190. And so forth.

 

[Dr. Lecter]

Last week I did a dive planned for an hour at 170. I brought laminated tables for 160-210 with bottom times ranging from 30mins to 90mins.

So one side will have "160" with stop times for 30min, 40min, etc. The other sides has 170'. Then another laminated sheet has 180 and 190. And so forth.

Don't forget lost gas(es) figures for each and every depth/time combo. With 2-3 deco mixes, you're going to need a bigger wetnotes I think this kind of contingency planning is a great reason to use computers within a hard plan...there's no point in having tables for a contingency for which you lack sufficient gas so cut one backup for 90 minutes at 210', take a computer or two, and go dive. Basic BT puck in a pocket with the table in case things go completely sideways.

It may just be that I hate printing/writing out tables.

 

[jadairiii]

Some of you may not be old enough to remember but there was a deco program called DECOM. You could cut and print tables like AJ is talking about. Would create .rtf (.rft??) document. Straight Buhlmann tables.

Simple.

 

[PfcAJ]

Don't forget lost gas(es) figures for each and every depth/time combo. With 2-3 deco mixes, you're going to need a bigger wetnotes I think this kind of contingency planning is a great reason to use computers within a hard plan...there's no point in having tables for a contingency for which you lack sufficient gas so cut one backup for 90 minutes at 210', take a computer or two, and go dive. Basic BT puck in a pocket with the table in case things go completely sideways.

It may just be that I hate printing/writing out tables.

lost deco gas is pretty simple. 1.5x the time and share your buddy's deco gas. I don't really see a need for special tables. Ymmv.