Three dives in one day against the rules?

[Jasminka]

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.

FInally a sensible answer, not talking down different schools! I suppose that a resonable person would know that the instructor is the most important and not the school. This is exactly what I asked...I was wandering how can you plan a third dive if the give pressure groups and RNT after the first dive only.
But then, the "dive 2" cant give you the exact data to plan the third dive if you take into account that you've already been satured on the second dive and not 0 RNT? Computor can tell the difference, but can the tables? I am asking this because we only did calculations for the second repetitive dive and not the third.

 

[evil_xander]

OT, Jasminka, but could you please fill in some diving related info in your profile? No picture needed, thanks!

 

[mislav]

Personally I think you should keep an open mind and see how things go.

Exactly how I see this. Taking it easy, diving and minding my own business, smiling along the way...

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

Hm, if you know how to use tables how come you ask question about the basics?

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

Actually, the thread was whether CMAS had any rule against making three dives in one day as I was told at the club that it did.

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.

I dive using common sense and knowledge. I follow the rules. But, I don't follow nonsensical non-existent rules that someone makes on the spot or are a product of someone's lack of knowledge.

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

Agreed.

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.

Can't within that club since they have issued a new rulebook that forbids three dives in one day regardless of depth and bottom time and calls such diving "unsafe".

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

I'm glad to hear this, DAN is a great organization providing great support to divers worldwide and the least we can do is support it back as much as we can.

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.

Sorry Mike, no idea. I'm PADI and not CMAS and can't really comment on what revisions they have made over the years. I have yet to see the Croatian CMAS version, I am only familiar with the International (English) one.

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.

Honestly, I doubt this was on their minds when they started setting the rules. Besides, they have admitted to me personally that my diving skills are "super". Yep, that's a quote. Also, those rules are for all of them to follow, not only me. In a way, their rules make sense - most of them are unsafe and dangerous divers! Disorganized, dangling equipment, damaging reefs, silting, no buoyancy skills, no stamina, panicky... I could go on and on and have a proof and an example for everything I said here. Sure, some of them are competent divers, but once they start flaming PADI or limiting dives and then you witness firsthand how little they know... :shakehead

FInally a sensible answer, not talking down different schools!

Personally, I think CMAS is a great school and I have at least two good friends who are CMAS instructors. I have nothing but respect for these guys and I don't see anyone recently "talking down" CMAS - only the club in mention and its rules.

I suppose that a resonable person would know that the instructor is the most important and not the school.

Are you telling me you guys have a bad instructor then? Since many of you don't know the basics... what other conclusion does this lead us to?

Anyway, this has been debated many times before on SB. Some say yes, some say no - my personal view is that it's neither. It's the student. He who wants to learn will do so from the worst instructor and from the worst agency. Just as I did - although I was lucky to have several top notch instructors.

This is exactly what I asked...I was wandering how can you plan a third dive if the give pressure groups and RNT after the first dive only. But then, the "dive 2" cant give you the exact data to plan the third dive if you take into account that you've already been satured on the second dive and not 0 RNT? Computor can tell the difference, but can the tables? I am asking this because we only did calculations for the second repetitive dive and not the third.

Again, if you know how to use tables you should know the answer to this:
You do take into account the RNT from the second dive. What you have to do is simply calculate what group you're in after the second dive (with added RNT from the first), then calculate how long your surface interval is and what group you end up with this time. Depending on the group you are in and the planned depth of the next dive - you can safely plan the third or any consecutive dive using tables.

 

[Sideband]

FInally a sensible answer, not talking down different schools! I suppose that a resonable person would know that the instructor is the most important and not the school.

There are some reasonable people here that would argue that point with you.

This is exactly what I asked...I was wandering how can you plan a third dive if the give pressure groups and RNT after the first dive only.
But then, the "dive 2" cant give you the exact data to plan the third dive if you take into account that you've already been satured on the second dive and not 0 RNT?

Hopefully you would be FAR from saturated (saturation would require many many many hours of deco). The whole idea is pretty easy. Dive 1 you absorbe some nitrogen. During your sufrace interval you off gas some of that N2. What is left at the time of your second dive is your residual N2 which you account for by having a shorter NDL time. After dive 2 you have absorbed more N2. That, plus your residual from dive 1 is your total N2. You then off gas some more during the next surface interval. The N2 remaining determines your max dive time for a given depth. You do the dive, add the new N2 to your last residual and you have your new total N2. You off gas during a surface interval.....

Computor can tell the difference, but can the tables? I am asking this because we only did calculations for the second repetitive dive and not the third.

So, bad instructor or bad ""school"?

 

[Meng_Tze]

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

Gary D.

I wish I could do 3 or more dives/day.............. just not enough time in the day.

 

[Jasminka]

What I ask for is scientific proof, here is the answer I got from DAN:
I quote:
There is unfortunately no scientific data available as yet that can provide accurate information for multiple dives per day. In terms of general safety dive medicine professionals recommend that if you chose to dive aggressively that follow the recreational guidelines regarding no-decompression limits, use surface intervals that are longer than the minimum required and to stay well hydrated. The more dives that are done in the day the greater the potential fluid loss is. As far as covering the treatment for an aggressive diver we can only answer for DAN America. We would cover the expense regardless of the diver's profiles and diving style. If we can be any further assistance do not hesitate to contact DAN.
Divers Alert Network

Marty McCafferty, EMT-P DMT-A
DAN, Medical Information Specialist
Department of Anesthesiology
Duke University Medical Center
(919) 684-2948 ext. 286
(800) 446-2671 ext. 222
(919) 493-3040 Fax
E-mail: mmccafferty@dan.duke.edu

So are we happy now?

 

[mislav]

I wonder if you understand the answer you've got from DAN? It kind of proves our point...

 

[Gene_Hobbs]

Just to throw something else in the mix...

Lang, M.A. and R.D. Vann (eds.). 1991. Proceedings of the AAUS Repetitive Diving Workshop. Duke University, NC. 339 p.
RRR ID: 4243

Although diving is a relatively safe activity, all persons who dive must be aware that there is an inherent risk to this activity. Currently, the risk of decompression illness in the United States is estimated at 1-2 incidents per 1,000-2,000 dives for the commercial diving sector, 2 incidents per 10,000 dives for recreational diving activities and 1 incident in 100,000 dives for the scientific diving community.
Recreational Diving
Peter B. Bennett, Moderator

1. Scientific diving programs provide continuous training, recertification and dive site supervision, which helps maintain established safe diving protocols. Recreational divers, who may lack such direct supervision, need to be aware of their need to stay within established protocols, especially when making repetitive dives over multiple days, in which the risk of DCS may be higher.
2. It is recommended that attention of divers be directed with emphasis on the ancillary factors to decompression risk such as fitness to dive, adequate rest, hydration, body weight, age and especially rate of ascent which should not be more than 60 feet per minute.
3. Divers are encouraged to learn and remember the signs and symptoms of decompression illness and report them promptly so as to receive effective treatment as rapidly as possible to prevent residual injury.
4. The use of oxygen breathing on the surface, whenever possible via a demand regulator mask system, to insure the highest percentage of oxygen to the patient, is recommended while awaiting treatment if decompression illness is thought to be present. The use of 100% oxygen in the water while awaiting treatment is not recommended for recreational diving.
5. There is a strong need for more controlled data on the relationship of decompression illness to multi-level, multi-day diving, especially with the provision of baseline data. Such a study could be made from information gathered from closed groups such as certain island areas and liveaboard fleets where heavy recreational diving activities occur.
6. To help obtain information, dive computer manufacturers are encouraged to provide data loggers to computers so that a permanent record is available of dive depth, dive time, rate of ascent, etc. as close as every minute. This should be coupled with detailed accident reporting forms (e.g. DAN form) in the case of an accident.

and for those that want to do things in "reverse"...

Lang, M.A. & C.E. Lehner (eds) 2000. Proceedings of the AAUS Reverse Dive Profiles Workshop. Smithsonian Institution, Washington D.C. 295p.
RRR ID: 4244

 

[DiverBizz]

Well, I know that my OW instructor did our class and then another class after we were done. Hmmmm I wondered about the CESA drills with the students that could wear on you if they go too fast. CMAS is one I have not hear of what does it stand for?

 

[miketsp]

Well, I know that my OW instructor did our class and then another class after we were done. Hmmmm I wondered about the CESA drills with the students that could wear on you if they go too fast. CMAS is one I have not hear of what does it stand for?

http://www.cmas.org/

CMAS - Confédération Mondiale des Activités Subaquatiques