DCS Incident - Salient lessons to be learned

[MB NZ]

vPlanner... assumes a square profile.

yes, that is a major limitation of v-planner and similar software.

If the victim's computer really said this was a no-deco dive (I'm not all that certain about that aspect), it sounds like a really good reason to not ride computers on deep dives.

the dives described are well within the realms of "recreational" diving and could be completed within NDL on most recreational dive computers. while it is entirely possible to get yourself in to a world of pain on a 29 metre dive, i would not consider this "deep diving", although this is a somewhat subjective term.

 

[Centrals]

While it's nice to share the story, I think you missed the point.

You did a 25m dive for 40 minutes on air. vPlanner shows this as requiring almost 20 minutes of deco, which you didn't do.

The surprising part isn't that Fred got bent, but that nobody else was bent along with him.

Also, I can't imagine relying on my credit card for SCUBA insurance. That's what DAN is for. Buy a plan without a depth limit and it won't be a problem.

flots.

I have no idea what the DAN Prefer Plan in USA covered. But DAN Prefer Plan(Asia Pacific) for unlimited depth is for diver with appropriate certification ONLY. There is no point for a recreational diver to purchase even the Master Plan(50m) because they are not certified to dive beyond recreational limit(30-40m).
A 25m dive with 40 mins bottom time is certainly a deco dive. But a total dive time of 40mins with 25m max is another story.

---------- Post added September 20th, 2014 at 07:06 AM ----------

vPlanner calls for a bunch of deco, and assumes a square profile.

How would you plan a non-deco multilevel dive on V Planner with 25m max and surface after total of 40mins?

 

[flots am]

How would you plan a non-deco multilevel dive on V Planner with 25m max and surface after total of 40mins?

With the right gas. Nitrox 36 in this case.M ----------

yes, that is a major limitation of v-planner and similar software.

The software is fine. It's the diver that was bent.

flots

edit:

vPlanner does multilevel dives just fine; however you need to have planned the dive before splashing, which would give you the opportunity to make sure you have a good dive plan (no deco if that's what you're planning), a good safety margin and enough gas.

If you're just going to dive until the computer beeps and says "go up," you're essentially trusting your life that it will be able to create and modify a plan on-the-fly that will get you back to the surface safely, not bent and not out of gas.

 

[Centrals]

With the right gas. Nitrox 36 in this case.M ----------

What is the V-Planner non-deco dive profile for EAN 21 at 25m max and total dive time of 40mins?
Please don't tell me that your V-Planner cannot plan multi-level non deco dive!!

 

[Dr. Lecter]

I have no idea what the DAN Prefer Plan in USA covered. But DAN Prefer Plan(Asia Pacific) for unlimited depth is for diver with appropriate certification ONLY. There is no point for a recreational diver to purchase even the Master Plan(50m) because they are not certified to dive beyond recreational limit(30-40m).
A 25m dive with 40 mins bottom time is certainly a deco dive. But a total dive time of 40mins with 25m max is another story.

That's right, you don't. So you might want to caveat your post with something about how none of those limits apply to DAN USA plans. For DAN USA, the basic el cheapo plan will cover an incident occuring as part of any non-commercial/professional dive planned to 130' regardless of whether you're certified for OW or whatever past that. The other two DAN USA plans will cover an incident occuring as part of any non-commercial/professional dive planned to any depth whatsoever, regardless of what you're certified for. If you're certified to OW only, hold a Master or Preferred DAN USA plan, and get bent on a trimix deco dive to 100m, you would still be covered.

However, nobody should take some guy on the internet's word for this stuff. Buy insurance, read the coverage limits cover to cover, and ask the insurance company to clarify limits if you're not sure what they mean.

 

[raftingtigger]

Diving Dubai, thanks for the write up. I see the following lessons:

1. DCS can happen even if the computer or software says you probably will be safe. Everyone's physiology is different, and even varies day-to-day. An undeserved hit should make the diver consider evaluation for a PFO.

2. If you suspect DCS put the victim on as high an O2 percent as you can for as long as you can. Kudo's to the OP's wife.

3. Using nitrox with air "tables" can give you an extra margin of safety, but see point #1 above.

4. Carry and know your dive insurance limitations.

 

[Jim Lapenta]

The free version of v planner will not let you do some dive profiles. I have always had the full version and you can indeed plan all kinds of weird multi level profiles on it. Deco and non deco. It's actually quite easy to do once you know how.

 

[Centrals]

However, nobody should take some guy on the internet's word for this stuff. Buy insurance, read the coverage limits cover to cover, and ask the insurance company to clarify limits if you're not sure what they mean.

Indeed! Read the small print.
And even for an organization like DAN would have different coverage for different region.

 

[Seymour Fisch]

Even without planning software, it sounds as if this dive might have been on the edge of NDL. From the original post, it sounded as if the dive was basically a descent to the wreck between 18m and 29m, hanging around down there as long as possible, then slow ascent, safety stop, ascent to surface. If you take that as a square profile to 24m, let's see... that's about 80 FSW. Iirc, on my PADI RDP, that's a NDL of 30 minutes. With the quoted 40 minutes total dive time, subtract 3 minutes for the safety stop, and 3 minutes for a 10m/minute ascent rate, and you're still 4 minutes over the NDL. Assuming the true profiles were slightly more conservative, and with various computer algorithms, I could imagine all of their computers indicating that they were within NDL, but I'd guess that everyone would have been very close to the edge. Throw in some dehydration, fatigue, individual differences, and just bad luck (e.g., a few too many microbubbles just happen to run into each other in an inconvenient location), and the odds of someone getting bent go way up.

Kudos to Dubai Diver's wife, and a big thanks to Dubai Diver and everyone else for these threads. As a new diver, I learn so much from all of this. Wishing "Fred" a speedy and full recovery!

 

[MB NZ]

The software is fine. It's the diver that was bent.

the software that you use cannot manage multi-level dives. while this may be fine, it is a limitation. v-planner is just another tool, just like a dive table or dive computer. all have advantages and disadvantages and all can get you bent, there are no certainties in this game.