Three dives in one day against the rules?

[mislav]

DAN reports its member getting bends: 16 dives in a week on the last day of diving 3 dives to around 35, 25, 29 metres for about 40-50 minutes.

And this has to do with what exactly? Did you know that you can get bent even doing one single dive? DCS depends on a large number of factors - from sawtooth diving profiles to taking hot showers. I find it funny that I seem to be among the few that understand this in that club.

I also find it funny that you should throw DAN report at me since me and my buddy also seem to be the only direct DAN members in that club.

I was also wondering how do you plan your third and fourth dive if the table only show you the groups for the second consecutive dive?

Don't you know how to use the dive tables? You CAN plan repetitive DIVES with both PADI and CMAS tables. There are other tables as well, but I won't go into that since we're talking PADI and CMAS here. There's also such a thing as the RDP Wheel for multilevel dive planning. Then, there are computers - you can also use them to plan your repetitive dives.

Anyway, here's the breakdown of that day:

1st dive: time 13:28; bottom time 38 minutes; depth 22 meters
2nd dive: time 19:05; bottom time 33 minutes; depth 18 meters
3rd dive: time 21:57; bottom time 43 minutes; depth 11 meters

According to square profile PADI tables I'm out of NDL on the first dive, but in reality - this was a multilevel dive with only 1 minute spent below 20 meters. During most of the dive the depth was just 7-8 meters. I'll use max NDL time for PADI tables:

Thus, after the 1st dive I end up in group "S". Add surface interval and RNT to this and after the 2nd dive I end up in group "O". Again, one SI and RNT later and the third dive (the night dive) leaves me in group "N". Wow, I'm alive!

But, you say CMAS tables are better than PADI? Ok, here's where it gets interesting. First, let me point out that it clearly says CMAS tables are used for repetitive DIVES. Not one dive, but plural. If you haven't got CMAS tables let me point out this link for you: CMAS dive tables pdf. Check the page 11 - it clearly states "DIVES" with an "S".

Back to calculations:

According to CMAS tables, after the first dive I ended up with the group "F". After the surface interval I'm group "A". Adding RNT to the second dive and I'm back to group "F". Surface interval drops me down to group "A" one more time before the third dive after which I find myself in the group "E". At this point I'm done diving for the day and look what it says for group "E" on CMAS tables: "After 4 hrs my RNT is 0!" Again - I'm alive and bubble free the next day!

Incidentally, CMAS tables use Buehlmann algorithm which is also the one my Aladin uses but wasn't diving on it because I gave it to another club member to use. I dove using my other computer - Stinger which is even more conservative (and uses Haldane algorithm, but that's irrelevant) and I was well within limits of it as well.

 

[MauiScubaSteve]

If you do not know how to plan your 3rd and 4th dives with the tables, please buy a computer and learn how to use the plan function. All US Open Water instruction except SDI teaches table use for 3rd dives (SDI uses computers). PADi OW exam could be passed even missing all the table questions. Do we have a winner?

Jasminka, is there any information on the health and fitness of the bent member as well as info on surface intervals for the final day and was the problem before or after da plane?

 

[dbulmer]

Mislav,

Since you're new to that club I strongly suspect that the club members are checking you out over a number of dives to ascertain your skill level and whether they like you or not.

Since they don't know you, they may be being conservative to begin with and may relax their rules as they see you progress.

In club environments you often have a range of abilities from novice to instructor - there may well be people far more qualified than you who can comment on deco but they adopt club rules for club dives but dive differently outside the club environment. Personally I think you should keep an open mind and see how things go.

 

[Jasminka]

I do have a computer and I know how to use the tables.

It seems to me that this discussion is more about what CMAS or PADI allows or suggests, while it should be about the safety.

I think it is our free will to choose how to dive, you can obey the "rules" to avoid the problems or you don't have to. You can also do deep dives with air.

If you dont like the way somebody dives, don't dive with that person.

I am perfectly fine doing 2 dives a day. They already take most of my day.
So if, you want to do your three or four dives, go ahead.

Also, Mislav, you are not an only DAN member in the club:14:

p.s. the lady had bents right after the dive...after 44 hours she took the plane and it got worse..

 

[Jasminka]

If you do not know how to plan your 3rd and 4th dives with the tables, please buy a computer and learn how to use the plan function. All US Open Water instruction except SDI teaches table use for 3rd dives (SDI uses computers). PADi OW exam could be passed even missing all the table questions. Do we have a winner?

Jasminka, is there any information on the health and fitness of the bent member as well as info on surface intervals for the final day and was the problem before or after da plane?

44, in shape, said the report, felt the bent as soon as she got out of the water. felt ok after a while, no porblem, after 44 hours took the plane and it came back and got worse...
Who knows, maybe she had Fanta the day before like that diver training to break the record...

 

[miketsp]

..snip..

But, you say CMAS tables are better than PADI? Ok, here's where it gets interesting. First, let me point out that it clearly says CMAS tables are used for repetitive DIVES. Not one dive, but plural. If you haven't got CMAS tables let me point out this link for you: CMAS dive tables pdf. Check the page 11 - it clearly states "DIVES" with an "S".
..snip..

I really do not understand the pdf above.

The pdf above with a set of dive tables dated May 2000 looks like a highly censored and padded version of the "CMAS" tables I received when I got back into diving at the end of 2001 and did a CMAS refresher course.
While the table generally looks similar, the pdf table is not as extense with the longer bottom times for most of the deeper dives being eliminated and the tables for 54m, 57m, 60m and 63m have been totally eliminated. In general the 3m stops are all padded compared to my 2001 table.

The instructor that gave me my set of tables told me that my set is the latest version fully revised around the year 2000 and he showed me a set of older CMAS tables, supposed to based on the US Navy tables, which were much more aggressive.
And yet the pdf above carries very old copyright markings from 1986 and 1993.
So how is it that an older table is less aggressive than my revised table from 2001?

I suspect that one of the problems is that various national agencies are affiliated to CMAS, but each publish their own material under the CMAS logotype.

Regarding the 2 dive limit for CMAS, I believe that some confusion also comes from the labelling of the CMAS table (at least the one I have).
Sheet 1 is labelled "dive 1" and sheet 2 is labelled "dive 2". The instructor was at pains to explain that "dive 2" has to be interpreted as "repetitive dive" and used cyclically for dives 2, 3, 4 etc.

 

[Sylvain]

PADi OW exam could be passed even missing all the table questions. Do we have a winner?

da plane?

Correct me if I am wrong but all agency that I have work for NAUI PADI ACUC req you to have 100% on dive table during the exam??????

 

[Gary D.]

Out in the working world you hope that you only have three dives in a day.

Gary D.

 

[beester]

Mislav,

Since you're new to that club I strongly suspect that the club members are checking you out over a number of dives to ascertain your skill level and whether they like you or not.

Since they don't know you, they may be being conservative to begin with and may relax their rules as they see you progress.

In club environments you often have a range of abilities from novice to instructor - there may well be people far more qualified than you who can comment on deco but they adopt club rules for club dives but dive differently outside the club environment. Personally I think you should keep an open mind and see how things go.

I believe this is sound advice! This is the same course of action that would be taken I believe in my club. First check out the new guy... see how he reacts and behaves underwater before deciding on his skill level. I don't think they would take a new guy on north sea wreckdives if they didn't know him... no matter his certification level or federation. Maybe after a few dives you'll get a friendly nod and you'll be able to 'unofficially' dive more then 2 times a day. I still state however that in Belgium (CMAS) 3 or more dives a day are absolutely possible.

 

[glendivesalot]

The SSI standards are no more than 3 TRAINING dives in one day. You can make as many dives in a day as you want, given proper SI's. I have done six several times on liveaboards around the glove. It's easy to do, given the right mixes of Nitrox and getting in some surface intervals.