Computers that don't lock out tangent.
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It is actually really hard to get into this situation, basically you will probably have a ceiling of 3m and need to wait until either a few minutes after your buddy’s computer is clear or until you have to surface due to no gas.
The real circumstances are when a diver fails to understand they are in deco and simply surfaces without realising there is a problem. That diver benefits from being prevented in diving again and having the issue drawn to their attention.
To illustrate how completely bogus the assertions made on SB are: I took a Zoop on my final normoxic qualifying dive to 60m. It was set to air and I was using 40% and 70% for deco gases which it had no idea about. Here people would be telling you to expect it to bend at 20 odd metres what with all those RGBM deep stops being skipped, in fact it bent with a ceiling of 7m when I moved up to my 6m stop. Really the question is do you have enough gas to do the necessary deco or not? No computer will give you more gas.
As to being locked out while teaching, no amount of stupid ascents will bend a Suunto. Even practicing CBLs with people for the first time and taking too many goes to get it will not lock them out. The only way is to have a real stop and ignore it. Tbone can’t know this because he doesn’t dive them.
The two proper annoyances are beeping fast ascent alerts and getting stuck in gauge mode.
check post #22 from @tbone1004, had one of his AIs get locked out doing CESAs.
And while I accept you and @Diving Dubai 's assertion that it is difficult to do it does not change my position that a computer should never lock out; that programmed behavior is unacceptable for the reasons I have outlined.
And I agree on the guage mode locks, I outlined an example in this thread of that happening to my daughter.
You have two different conversations going on, lock out during a dive and lock out after surfacing. @tbone1004 ’s post sounds like it was after the dive.
No one likes a 24 or 48 hour lock out, but then also over simplify the issue. Just using the DSAT RDP as an example, the tables will “wash out” after a 6 hour surface interval, but “time to fly” guidelines are 12 hours,18 hours, or longer depending on the recent dive history. Clearly washing out the algorithm is not thought to be the same as completely clearing all tissue compartments.
A computer algorithm that recognizes there are limits to what can be predicted and/or calculated is completely understandable. One that does not have such limits is neither better or worse - just different, and another aspect of “less conservative.” You make choices on how extreme or conservative your dive profile is, and you make the same choice when you buy a computer.
If you choose to dive a profile (or repetitive profile) that is outside the operating design parameters of a given dive computer, and even outside the contingency parameters, why are you surprised if it basically says “forget this, I didn’t sign up for this.”
The same is true if accidentally diving in gauge mode. The algorithm is accounting for everything that happened in the last 24 hours or longer, and you are expecting it to knowingly ignore dives that it does know happened.
I dismiss tbone’s unsupported, third hand claims. I don’t believe it is true. I am of the opinion I could attach a Zoop to 20m of rope and a lump of lead and repeatedly throw it overboard and recover it all day long and it would be fine.
I suspect you have not been exposed to enough divers who clearly have no idea what the numbers on their computers mean. In general they don’t realise there is a problem unless it is made extremely clear. Turning red isn’t enough. Since they are going to get out of the water regardless the behaviour while above the stop doesn’t matter. It is preventing them getting back in that is important.
As for the computer being in charge, it is not, the diver decides to do what it suggests, the computer cannot make you go up or down or provide more gas.
If you think you know better than the people making computers why do you use one at all?
Wow, pretty over the top response there. You accuse tbone of lying and accuse me of being too inexperienced to have a valid opinion, all without any evidence of either assertion. Pretty outlandish behavior.
Jackd342 made a reasonable point earlier about differentiating between lock outs after a return to surface vs a lockout underwater, that differentiation has merit.
And as to your point on computers I chose a computer that does not lock me out for me.
RonR
Contributor
I’ll just offer some observations from the sidelines:
Violation/ no violation is binary. The real world of decompression is analog.
When a deco violation occurs, all that means is that for the particular settings and the particular algorithm, at that point the computer determines the risk level has passed over some threshold, set by the manufacturer and/ or the algorithm as acceptable for their market.
This doesn’t mean that the computer has gone “tilt”, overrun anything, or lost its ability to calculate a revised schedule. If any of the available conservatism settings (in our case these include age, workload, risk level) were set differently, or if the spacing between stops were set to a different value, or if the computer included additional risk level options (as, effectively, Buhlmann with GF does) the computer might deliver a result that is below the risk level selected and not show a violation.
A revised schedule might include additional time at shallower stops. Obviously, in the case of an extreme violation, the shallowest possible stop might end up being below the diver’s current depth. We can calculate these schedules consistent with the algorithm to a point, but the risk level increases with with the scale of the violations. We do warn, post dive for 24 hours, with a prominent and unavoidable page that must be acknowledged to reach the dive screen, but leave it up to the diver to determine how they handle any violation- re-descent, continuing diving, or seeking aid.
That's just our approach for our intended customers. Locking out post dive after a violation is not an unreasonable approach, but it's not our choice. I find it hard to understand how locking up during a dive improves diver safety under any circumstances.
-Ron
Violation/ no violation is binary. The real world of decompression is analog.
When a deco violation occurs, all that means is that for the particular settings and the particular algorithm, at that point the computer determines the risk level has passed over some threshold, set by the manufacturer and/ or the algorithm as acceptable for their market.
This doesn’t mean that the computer has gone “tilt”, overrun anything, or lost its ability to calculate a revised schedule. If any of the available conservatism settings (in our case these include age, workload, risk level) were set differently, or if the spacing between stops were set to a different value, or if the computer included additional risk level options (as, effectively, Buhlmann with GF does) the computer might deliver a result that is below the risk level selected and not show a violation.
A revised schedule might include additional time at shallower stops. Obviously, in the case of an extreme violation, the shallowest possible stop might end up being below the diver’s current depth. We can calculate these schedules consistent with the algorithm to a point, but the risk level increases with with the scale of the violations. We do warn, post dive for 24 hours, with a prominent and unavoidable page that must be acknowledged to reach the dive screen, but leave it up to the diver to determine how they handle any violation- re-descent, continuing diving, or seeking aid.
That's just our approach for our intended customers. Locking out post dive after a violation is not an unreasonable approach, but it's not our choice. I find it hard to understand how locking up during a dive improves diver safety under any circumstances.
-Ron
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@KenGordon how is it third hand if I was there when it happened? No I didn't see his computer during that dive, but I know he was diving the same profiles I was, my Shearwater on 50/70 was nowhere close to NDL, and his Suunto locked out. What caused it, I don't know and frankly don't care because I would never dive a Suunto, but the fact that they can do it, is something that is a 100% deal breaker for me when choosing a dive computer. No, it doesn't matter for the vast majority of people, but when teaching, I can't afford to have a computer decide to lock me out for any reason, ever.
Doesn't mean it didn't either. We assume that under normal circumstances those "garden variety" violations will not push a device out of bounds, but we can't actually know without knowing the exact circumstances and the exact code running inside the computer in question at the point when violation occured.
If you missed a mandatory deco stop and are continuing on your dive because you know better, then you obviously don't need no stinking computer. Why should the computer keep computing when it's obviously not needed? A computer, locked or not, is useless at this point, so who cares if tries to figure out exactly how bent you are or goes playing Global Thermonuclear War with itself from here on.
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