Hello From Tulsa! 3rd dive = Decompression Camber

[undRH2OdivR]

first I wouldn;t say 110 for 20 is way over the limits.. Its over for padi tables, but US navy tables allow 110 for 20 surfacing as a "G" diver.. On many deco programs (0% conservatism) if you put in 110 for 20 , most come up with around 3 minutes of deco, so if a safety stop was completed, this would have beenok also..

Dehydration raisesthe risk significantly.. What was the exact profile for the dives that caused problems afterwards?

I would say way over the Padi limits. The Padi RDP does not even have a table for the 1st dive to 110ft for 20min. so he has already exceeded his limits. And I don't think he was diving to the US Navy tables ( if any tables at all). How does one calculate a first dive to these depths using the RDP ( Padi )? What would be your surface interval?

 

[ekiledjian]

Hello Everyone! My name is Matt, and have only 3 dive under my belt. Me, my wife, son and 21yo nephew went to Grand Cayman August 2004 and had a blast despite what sounds like a horrible vacation. We made the best of all situations.

[ SOME TEXT REMOVED ]

Sorry, for the long letter but I’m sure you don’t have anything better to do! LOL

Thanks for listening,
Matt

P.S. here are some picts from my trip.
http://www.mattrandolph.com/cayman/

I see that you where diving wihtout a wetsuit. Why? I usually dive in hot water destinations but always wear a 3mm full body to protect me from inadvertently being stung by something.

Better luck next time


Edward
Canada

 

[DI_Guy]

Hi there Matt and a sincere welcome to the SB, I am sincerely glad that you are OK. As many have commented, you did put yourself a great risk. I tend to blame the dive operator and the DM for not verifying your past experience. My daughter lives in the Cayman Islands and the DM took her to 103' on her 12th dive as an OW diver. I was upset about that. I hope that this is not the NORM for the CI dive operators. BTW nice pics. I've been to the CI and it brought back memories. Learn from the people here. Great people, Great chats, & Great info...

Al (in Canada)

 

[Kim]

I would say way over the Padi limits. The Padi RDP does not even have a table for the 1st dive to 110ft for 20min. so he has already exceeded his limits. And I don't think he was diving to the US Navy tables ( if any tables at all). How does one calculate a first dive to these depths using the RDP ( Padi )? What would be your surface interval?

This is not really about the tables. Decompression theory is exactly that - theory. No-one knows the facts, they just have a bunch of theory plus experience to formulate probabilities. Mostly those probabilities keep us all safe - if we play by the rules. Some tables such as PADI's are intentionally made to stay safely within the perceived limits. Other tables attempt to closer approach the boundary of reality. Make no mistake here, a seizure at depth or bubble formation in your blood and muscle tissue at the surface is a very real reality and not to be taken lightly. This is why we have tables AND training.
In this case training was obviously exceeded and ANY tables would have been impossible to use because there was no sure documentation of depth and time - just a large amount of 'about' and 'I think'.

Let's not bicker about which set of tables says what - let's try to keep everyone safe.

 

[Rick Inman]

Dive depths and locations:
1. 20ft lake
2. 20ft lake
3. 20ft lake
4. 20ft lake

Can one of you PADI instructors tell me, isn't there a minimum depth that has to be reached during OW training dives before someone is PADI certified?

This whole thing just sounds like what I've seen on the few tropical dive boats I've been on, meaning, using one of the three methods of vacation dive planning:

1) Jump in and see what your computer says during the dive

2) Jump in and see what someone else's computer says during the dive

3) Jump in and follow the DM ("Trust Me" dive)

Happens every day. We're just talking about it because Matt got hit and wanted to tell us all about it.

 

[mwpowell]

It seems to be rather clear that 'exact' profiles are not available as the diver isn't sure about anything. I hope that at the very least this experience has taught him that diving like this is just plain stupid.

Yep, that is exactly the lesson to be learned from this.

Matt,

When you dive in Cozumel, take the time to check your NDL before jumping in the water. Monitor your depth and time throughout the dive. Since you now have an indication that you are susceptible to DCS, you should plan on ending the dive way before you hit the NDL. Your dive plan doesn't need to be complicated.

Here's an example of how you could do your dive plan in Cozumel.

DM: "Here we are at reef X. The max depth is going to be 60 feet. We want you all to return to the boat with at least 750 psi."

Diver: Checks PADI OW table. For 60 feet the NDL is 55 min (adjust if this is a repetive dive). I don't have a lot of experience at this depth, and with the experience I do have I got bent. I better play it safe and spend no more than 45 min on this dive. I'm starting the dive with 3000 psi, so when I hit 2000 psi I'm gonna start my ascent. I'm gonna do a safety stop at 15 feet for at least 5 min, where I plan on practicing my bouyancy skills while looking at all the poretty reef creatures below. I should surface with at least 1000 psi in my tank.


Regards,

Mike

 

[miketsp]

Can one of you PADI instructors tell me, isn't there a minimum depth that has to be reached during OW training dives before someone is PADI certified?

This whole thing just sounds like what I've seen on the few tropical dive boats I've been on, meaning, using one of the three methods of vacation dive planning:

1) Jump in and see what your computer says during the dive

2) Jump in and see what someone else's computer says during the dive

3) Jump in and follow the DM ("Trust Me" dive)

Happens every day. We're just talking about it because Matt got hit and wanted to tell us all about it.

Rick,
I think many readers will interpret that you are objecting to all 3 options. While I agree that (2) & (3) are to be avoided, number 1 is acceptable given the following conditions:
a) the computer is known to be reliable and conservative,
b) the diver is familiar with what the tables would give at this depth,
c) the practice of "riding the computer NDL" is avoided,
d) each diver in the buddy pair has his own,
e) the divers have done some gas planning for the dive or know how to calculate their rock-bottom on the fly.

I don't want to get into a computer/tables discussion. There are enough of those on SB already.
Just making the point that thousands of dives are done on this basis every day.

 

[RonFrank]

Matt,

The past is the past, and you are LUCKY! I'm also new to diving. Based on what I've read I am surprised by a few things:

1) No understanding of what depth the OW cert suggests (60ft BTW).
2) No dive plan.
3) No idea of how deep you were.
4) No idea how long you were down.

The concepts of danger at depth, plan the dive - dive the plan, and monitor your air/BT/depth on a constant basis were VERY clear in the material, and repeated in the classroom, and on every dive by the instructors from my OW. We also did a bit more than 20 ft (35 on the last dive) and that was at altitude.

Just because you are with a group, does not guaranty save diving.

I'm not here to be your mommy, or flame, or spank you for things in the past. I would however suggest you take some time to watch the video's and re-read the OW material on dive planning, and DCS.

People here are generally a friendly bunch, but they take safe diving VERY seriously, so understand that the comments are ment as constructive.

Since you have been hit once by DCS, I would suggest you read some of the accounts on it. One chamber ride means you did not get hit bad. The next time, it could be MUCH worst, and COZ is famous for deep wall dives, so you need to be careful.

You made quite a "SLASH" upon arrival!!

Ron

I didn't use someone else computer. After the dive and I started getting symtoms on the boat, one of the other divers checked his computer to see how deep we actually went. And I don't feel like I dove out of my control. At no time did I feel out of control.

After reviewing my dive dive table, it looks like I should have followed the "emergency decompression" rule. It says "If a no decompression limit is exceeded by no more than 5 minutes, an 8 minute decompression stop at 15ft is mandatory." I did not do the 8 minute decompression stop.

 

[eponym]

Can one of you PADI instructors tell me, isn't there a minimum depth that has to be reached during OW training dives before someone is PADI certified?

I'm SSI, not PADI, but the standards allow training dives to be quite shallow. The WRSTC standards define an OW Scuba Training Dive as being "at least 15 minutes at depths between 15 and 60 feet."

Optimum training IMO will work down to 50-60 feet on the fifth and last checkout dive (which appears to have been skipped in Matt's training) if the students are capable and the conditions are good. Making OW dives shorter or shallower than optimum is allowed under the standards, if conditions and safety concerns so dictate.

But the depth of your training dives defines your competency, which is why 60 feet is given as the maximum depth a new OW diver is qualified for. I'd guess that if Matt continues to dive, he'll someday look back on progressing directly from checkouts at 20 feet to 100 feet as a mistake. I'd say when planning your first dive trip, choose a location that offers good dives in the 30-60 foot range so you can have a great time without being tempted to dive beyond your competency.

-Bryan

PS Welcome to SB, Matt! Glad you're okay.

 

[Rick Inman]

Rick,
I think many readers will interpret that you are objecting to all 3 options. While I agree that (2) & (3) are to be avoided, number 1 is acceptable given the following conditions:
a) the computer is known to be reliable and conservative,
b) the diver is familiar with what the tables would give at this depth,
c) the practice of "riding the computer NDL" is avoided,
d) each diver in the buddy pair has his own,
e) the divers have done some gas planning for the dive or know how to calculate their rock-bottom on the fly.

I don't want to get into a computer/tables discussion. There are enough of those on SB already.
Just making the point that thousands of dives are done on this basis every day.

If a diver is doing your "E", then thry'er NOT doing my "#1".