certification limits and how they are considered now days....

[Bazzathemammoth]

Shirley common sense must prevail at some point. Just because you have a certificate that says X doesn’t necessarily mean you should do it. Dives below 30m/100ft quickly get more challenging.

Being experienced enough to know your limitations is critical. Otherwise it’s perfectly reasonable for a skipper to impose limits shallower than your worthless certification.

I agree with this. Unfortunately, common sense ain't common and it's easier for an op to say you need X to dive Y deep than for them to try and figure out if you are experienced enough to be aware of your own limitations.

I don't think my skills changed much (if at all) from doing AOW, but it magically gave me the ability to do way more interesting dives with ANY dive op here in NZ. It was a worthless cert to me from any other perspective.

If you don't like it, dive privately. I did that for a long time with my open water cert. There ain't no scuba police to arrest you for not following the "rules" (agencies recommendations).

One of my experienced (2000+ dives) dive buddies used me as an example of why cert doesn't mean much. He would dive with me over many of the dive instructors that he knew when I was "only" open water with not many dives. Once you factored in my boating, freediving, snorkelling, surfing and general outdoor experience I am more capable than my SCUBA training might indicate.

Oh and diving with him taught me way more than any course. It was fantastic, he taught me more about scuba and I taught him and his wife sailing. We had a great time!

 

[Wibble]

Reading about some of the arbitrary limits and requirements that appears to be imposed upon divers in Australia and other countries is interesting. Designed for the lowest common denominator and convenience for the dive police, not the tourist with the experience to dive safety well beyond the legal limits imposed.

 

[TMHeimer]

Reading about some of the arbitrary limits and requirements that appears to be imposed upon divers in Australia and other countries is interesting. Designed for the lowest common denominator and convenience for the dive police, not the tourist with the experience to dive safety well beyond the legal limits imposed.

Agree. I guess too many incidents at some point with OW divers getting in trouble resulting in Ops having to legally protect themselves. "No swimming when lifeguard off duty", "swim between the flags only" , 'red flags up, beach closed to swimming"-- doesn't matter if you are lifeguard yourself or even an olympic swimmer. Just the multitude of rules we have today (my friend said that to me circa 1988...).
Nova Scotia-- no signs. Park by the ocean and do whatever you want, Not enough people (or lawsuits) here so we get such freedoms. Once in a while "Swim at your own risk"-- doesn't that relieve toe gov't. of any legalities? If not, it should.

 

[Centrals]

My personal approach after qualification:
1. 18m for OW.
2. 30m for AOW. I believe my AOW training back in 1996 was allowed to 40m.
3. 30m+ for deep specialty. I did that course for MSD.
4. No planned decompression dive for recreational dive.

 

[McHugh]

I have the Ame feeling, when being certified with vdst, I was told I may dive up to the mod of normal air (21%;1.4 ppo2: 54 in theory) so the 40m limit for rec diving. But when being at a paid and SSI base I was told VDST*/CMAS* is the same as OWD and therefore i mustn't go deeper than 18m. When looking it up on the VDST page, the advice is bound to the age, and they recommend a maximum depth of 40 meters from the age of 16 (8-9:5m; 10-11:8m; 12-13:12m; 14-17:25m; 16-17 with an adult:40m; 18+:40m). In the same booklet the *-Diver is seen as equal to a PADI AOWD or a SSI Advanced Adventurer (see picture). In the end, it comes to experience and behavior (e.g. Trimm) when being submerged.
As a funfact: VDST requires a certain number of dives within 15-25meters before you are allowed to take the 2* course

 

[boulderjohn]

Just a summary of some key points....

• Dive agency depth standards are required for instructors on training dives only.
• Dive agencies suggest that you extend your training limits through further training and experience.
• No training agency has the legal authority to limit the diving you do on your own.
• Dive operators have the authority to limit diving done through their operation and can impose any limit they wish. They may limit divers to training limits if they choose.
• Local governments have the authority to limit diving done in their areas of control in any way they wish.

 

[wetb4igetinthewater]

There are hard laws, and they are inflexible laws, and they are absolute laws. They are called the "laws of physics," and they include a death penalty. Those are the laws you'd best obey.

Reminds me of a t-shirt I saw:
GRAVITY
OBEY THE LAW!

Shirley common sense must prevail at some point.

Okay, in all seriousness, what John said.

 

[dmaziuk]

“The 130-foot limit is an arbitrary depth originally adopted by the U.S. Navy because it gave Navy divers about 10 minutes of (no-deco) time on compressed air; going any deeper on air made no sense to the Navy because the time available to do useful work was simply too short,” writes Lawrence Martin in Scuba Diving Explained: Questions & Answers on Physiology and Medical Aspects."

Subsurface gives 3 minutes on ZH-L+GF75/85. IIRC there is a French agency that certifies to 60 msw based on just under 1.5 PPO2... that's the calculated numbers, as the above says IRL you don't get much time for anything down there. Likely none at all on Al80.

 

[Bazzathemammoth]

Subsurface gives 3 minutes on ZH-L+GF75/85. IIRC there is a French agency that certifies to 60 msw based on just under 1.5 PPO2... that's the calculated numbers, as the above says IRL you don't get much time for anything down there. Likely none at all on Al80.

They use ppo2 max of 1.6 for nitrox and decompression on back gas up to 10 mins as part of their recreational standard as well as the bounce dives to 60m (or was it 5 mins deco, something like that?).

 

[boulderjohn]

Subsurface gives 3 minutes on ZH-L+GF75/85. IIRC there is a French agency that certifies to 60 msw based on just under 1.5 PPO2... that's the calculated numbers, as the above says IRL you don't get much time for anything down there. Likely none at all on Al80.

I am not sure what the point is for the last few posts related to dive time at 130 feet. That depth limit for recreational diving, particularly on nitrox, shows 1) the difference between Navy divers and recreational divers and 2) the difference between table diving and computer diving.

1) A Navy diver going to any depth is there to accomplish a task, and that task will usually take time. A recreational diver going to a depth like 130 feet will likely be hoping to see a specific sight. That "task" may only take a minute or two.

2) With tables, a diver going to that depth, even if only for a minute or two, must begin the ascent upon reaching the maximum bottom time, which (with the descent time counting for it) may be only a few more minutes of diving. That's a very quick dive, and the planned sight at the bottom had better be worth it. A computer diver can do a multi-level dive, with that time at maximum depth being only a fraction of the total dive experience.

An example of these two differences coming together can be seen in a very popular Cozumel diving site, the Devil's throat. Divers enter a coral swim through at 95 feet, take a steep plunge to about 125 feet, and then begin the ascent. They are only deeper than 100 feet for a few minutes, and, yes, some people do that dive on air with AL 80s. I did it this past summer on nitrox and a steel 120. My maximum depth was 126 feet, and my total dive time was 83 minutes, with most of that time spent weaving through shallower coral formations. I was never even close to the NDL.