How much risk was I at for DCS?

[supercritical]

@supergaijin: To clarify:
- I was taught that 'Total dive time' is the same as 'Bottom time' (it can be really misleading, methinks.)

- There was no group. Just me and the divemaster.

 

[chrpai]

I was taught that 'Total dive time' is the same as 'Bottom time' (it can be really misleading, methinks.)

Bottom time does not include ascent and decompression time. Total dive time does. This assumes a proper ascent rate and proper safety stop depth. Otherwise it becomes a multilevel dive with additional bottom time.

Here's a good thread: ( first few posts at least )

http://www.scubaboard.com/forums/ne...ring-diving/56290-bottom-time-definition.html

 

[supercritical]

That means that in my post, 'bottom time' should be relabeled 'dive time' for minimal confusion.

I've looked in my PADI Open Water manual, it defines 'bottom time' as:
"Bottom time is the total time in minutes from the beginning of descent until the beginning of final ascent to the surface or safety stop. (Note, for convenience, many divers use the time they leave for the surface until the time they return to it as bottom time. This is more conservative than the true definition of bottom time, and acceptable.)"
I went with the latter definition.

 

[chrpai]

(Note, for convenience, many divers use the time they leave for the surface until the time they return to it as bottom time. This is more conservative than the true definition of bottom time, and acceptable.)"

I don't have a problem with that statement provided that the diver understands the difference and knows they are doing it. Of course that means when you are on a 90' dive you are heading for the surface around 20 minutes instead of 25 minutes to account for your ascent and safety stop time.

There is still a difference between the two terms and the DM that taught you what you wrote previously didn't understand that.

And once you understand all this you get a computer so you get the conservatism and the advantages of multilevel.

 

[supercritical]

Either my instructor didn't tell me or I forgot.
Edit: More likely I forgot.

 

[Chilly_Dipper]

Back in December, I was making my 15th dive in Barracuda Lake, Coron. The divemaster took me down to 26.4 metres depth; twice my certification. .

26m ~ 85 feet.... PADI OW cert is 'good' to 60' you were 15 feet past that. No where near 2X the OW cert depth (2x60=120'). The question remains how long you were at that depth, which is what would be required to determine your risk of DCS.

That being said based on your post you were well beyond your comfort zone for diving, so you should not have followed the DM to that depth.

---------- Post added April 13th, 2013 at 11:45 PM ----------

@supergaijin: To clarify:
- I was taught that 'Total dive time' is the same as 'Bottom time' (it can be really misleading, methinks.)

- There was no group. Just me and the divemaster.

Without a computer you have to assume your maximum depth is were you spent the entire dive. This can result in extremely conservative bottom times, which is why most divers opt in for a computer to get maximum bottom time since they calculate your NDL on the fly. Personally I have done 2 hour dives with maximum depths @ 30m without ever going anywhere near decompression limits since my average depth was 10m for the majority of the dive.

 

[currier]

OP - As others have already pointed out, you conducted a multilevel dive that lasted 40 mins., not a dive to 26m for 40 mins.

When I was doing my OW and AOW I was given a neat device called the eRDPml (electronic RDP multilevel). It is essentially a calculator that crunches numbers such as (varying) depth x (varying) time = pressure group. I found it to be an extraordinarily useful tool to assist me while I began to understand the 'how & why' of introductory SCUBA.

For the pros - are these still given to students? do you like to make use of them when, say, planning or debriefing multilevel dives beyond OW certification?

 

[SailNaked]

The problem with calculating a dive with very acurate formulas bassed on guesses for your particular physiology and dive profile is that you can get results that do not match reality. you did not get DCS and any estimate on the probable likelyhood of your being bent in this situation is better put in your diary under "risked my life today, saw a shark and almost got bent" have fun with it, free your literary side.

please do not take this as a flame or other internet term for an not being an empathetic reply, I really do care, just not enough information to draw any reasonable conclusion on the OP.

 

[supercritical]

I don't want anyone to lose any sleep over this, as this topic was resolved a couple of pages ago.
@Chilly_Dipper: My certification is PADI Junior Open Water Diver. Max depth is 12 metres.
@currier: Yes, that's true (the multilevel part). What also worried me was the depth; what would have happened if something went pear-shaped (I'm a paranoid guy by nature.)
@SailNaked: I'll take that as 'not very much risk at all'. Didn't even see a barracuda, however.

 

[Hatul]

As others have noted, you really need to get your own dive computer. One diver using tables and another computer just is not going to work.