Please explain (teach me)

[Bubbletrubble]

I'm curious but what brand and model is that dive computer?

Your second dive profile was most conservative. I can't understand why the computer would prescribe a 5-minutes stop unless that's what the computer was automatically programmed to do - 5-minutes stop versus 3-minutes stop.

RTee initially brought this up. I'll expand on it a little...

Suunto dive computers may convert the "recommended" shallow safety stop from 3 minutes to a "mandatory" safety stop of 3 minutes or longer (5 min.?) if the ascent rate exceeded the Suunto-specified "maximum" rate (39 ft/min) instantaneously or 33 ft/min "continuously." The duration of the shallow safety stop is determined by the severity of the ascent rate violation.

It's certainly possible that the OP is confusing "stop" terminology: "recommended" safety stop vs. "mandatory" safety stop vs. "deco" stop. The most likely explanation of what happened is that the OP accidentally caused an ascent rate violation which resulted in a 5 min. "mandatory" safety stop. This was caused by suboptimal buoyancy control or raising the computer through the water column too quickly to read it. With some computers, it's also possible to cause an ascent rate violation simply by moving a wrist-mounted computer too quickly, particularly if it's attached to an arm/wrist that's being used to lift and exhaust gas from the BCD corrugated hose.

When it comes to operating a dive computer, it's always advisable to read the manual before using it.

Hope this helps...

 

[ben_wilson3301]

Safety stops are just that, for safety. Deco stops are mandatory, but both the tables and your computer are giving us NO Decompression limits. Any stop would then be just a safety stop unless you go over your limit and are no longer within your NO Decompression limits. In which case your computer would freak out, put you into deco and not let you dive for 24hrs in most cases.

 

[ianr33]

And yes, NetDoc; my PDC said to do stop at 15 feet for 5 minutes. My dive (last dive) went like this:

I very much doubt that is a DECO stop.

Every computer I have ever used has deco stops at 10 foot levels. i.e 10,20.30 etc.
Also,if it was a deco stop then when it first appears it will be for one minute.Not 5.

To the OP, what type of computer do you use?

 

[ozorowsky]

I use the aeris elite T3 computer.

I pulled the log software last night and yes there was one point when it said my ascent was 39ft/min vs 30ft/min

 

[Bubbletrubble]

I use the aeris elite T3 computer.

I pulled the log software last night and yes there was one point when it said my ascent was 39ft/min vs 30ft/min

Please let us know what your computer instruction manual says with regard to "recommended" safety stop vs. "mandatory" safety stop vs. "deco" stop. The manual should talk about how it deals with ascent rate violations, too.

Also, it might be helpful to let us know what personal adjustment setting you used to designate the level of conservatism for your dives in question.

 

[ozorowsky]

Please let us know what your computer instruction manual says with regard to "recommended" safety stop vs. "mandatory" safety stop vs. "deco" stop.

Also, it might be helpful to let us know what personal adjustment setting you used to designate the level of conservatism for your dives in question.

The aeris manual is very confusing. You can set the stop depths; but by default it is 15 ft.

As far as personal adj setting; I don't really have one I have concervative on or off; conservative is on

 

[fnfalman]

I use the aeris elite T3 computer.

I pulled the log software last night and yes there was one point when it said my ascent was 39ft/min vs 30ft/min

I have the same computer. It had never given me anything more than 3-minutes safety stops and I KNOW that I've gone faster than 39-ft/min a couple of times (CESA practice).

The safety stop is set at 15-ft but usually kicks in at around 20-ft. The only "conservative" setting is if one were to manually set the altitude level higher than the actual altitude.

 

[Thalassamania]

Probably none of those things.

There are two types of stops: obligated and optional (Safety).

Violating either of those will not necessarily give you DCS. However, doing them does not completely keep you safe from them either. There are many factors that affect DCS including ascent rate, breathing rate, temperature, hydration, sickness, elevation and so on. Its up to you to dive in a reasonable manner and mitigate those risk factors by decreasing your dive time (conservancy) or not diving until things are normal.

If you miss an optional stop, there is nothing to be done. You can continue to dive normally.

If you miss an obligatory stop, then you should stay out of the water for 24-48 hours and monitor yourself for symptoms of DCS. Call DAN and get to a hospital/hyperbaric chamber if you are suspicious.

Signs and Symptoms of DCS

Let's face it, walking up a hill requires "decompression." The accepted usage of "decompression stop" and "safety stop" has to do with the prediction of a model that you will bend as a result of a direct ascent to the surface at the approved rate of ascent in the former situation and that you will not in the latter case.

Unfortunately, many classes (past and present) never train diving with a PDC. They might say, "Read your manual" and that's about it.

Today's divers are increasingly using this capable and versatile tool to plan and execute their dives. Their use and how to avoid their abuse should be an integral part of every class. Many see this as "dumbing" down the class, I see it as showing due diligence in teaching them how to use a great tool.

I agree with you completely. Unfortunately many instructors are using dive computers as a way to minimize (and even eliminate) a subject that takes them too long to get across.

I have no problem with computer only courses (that when well done equip the new diver with a way to use a valuable tool, but leave them unprepared for when something goes wrong with their computer), but such courses don't really save any teaching time.

 

[fnfalman]

I just re-read the Elite T3's manual. There are only two stops: safety and deco. Safety stops are optional and you won't be penalized for it by the computer. Deco stops are mandatory and if you were to violate the deco stop (i.e. skip it or not following the depth/timer or both), the computer will lock out for 24-hrs before it will work again. There are no mandatory safety stop versus optional safety stops.

 

[The Chairman]

If we start really dumbing down the classes, will they serve Brawndo for the refreshment.

Brawndo. It's what Divers crave!

Its got electrolytes! The movie is a study of subtlety.