First dive at 40 meters - Newbies recreational

[Tribal]

Well. We stopped at 20 m and had fun. Then we stopped at 12 then at 5 where we had an extra cylinder. So, if my wife had had a problem, we would have had plenty of time to go straight to 5 m.

If you calculate the panic that at least one of you 2 would have after a gas loss, the time to solve that at 40m and the harder ascent while gas sharing as you are fairly new divers you wouldn’t have plenty of time. You would for sure be in deco after that aswell since you lose easily around 2 minutes at the bottom.

 

[Edward3c]

And

the 100 bar safety include the cylinder at 5 meters. I

You might want to rethink that. If the cylinder isn’t with you you can’t guarantee getting to it. You mentioned currents, they could drift you off so you can’t find it. Additionally, if there had been a gas failure as the 12m stop, an extra cylinder at 5m is useless.

It wasn’t my intention to be condescending, but to highlight areas you could do some research on.

 

[Raphus]

Thanks for posting your experience.
As far as i understand the stop at 20m was a deep stop.
The stops at 12 and 5m were stops not told by the computer, but you just did because you had air left. Right?

What kind of computer are you using?
And can you upload the dive profile?

Lots of advice was already given.

Most important (in my opinion) and something to improve on:
1. Dont use the tank at 5m in your gas calculation.
2. Never trust the DM.
3. 40m is no joke. I believe you, that you didnt feel narked. But you were 100%.
Dont ride the NDl at that depth. (tbh never ride the ndl).
4. Use your worst case sac and round it up for gas calculation. For example i have between 10l to 12l/min and just in rare cases it goes up to 14.
So i use 15 in mingas calculations. (doubled up to 30l/min in an emergency)

Then ofc dont do fin pivot and go to the deepest point first. But i think you already learned this one.

 

[Degenerate]

if you have a deco stop the it is a deco dive. You wrote your computer beeped to get you to do deco stops yes? You had to do a 2 min stop at 20m so that sir makes this a deco dive even if you say you only planned a dive not to exceed NDL limits. You say you had 1 min to NLD at 40m and struggled to ascend, while struggling you are finning and could have been in deco already but been back in NDL clock later as you ascended.

That massively depends on your dive computer though, and the settings it has.
You mention a 2 min stop at 20m which reminds me of a guy who accidentally ended up in deco on his Suunto Zoop, it called for some really strange deco stops and times, unreasonably deep and long ones.
One of the guys I dive most regularly with has a Suunto Vyper and it is a lot more conservative on NDL than my Shearwater with 70/90gf is.
On a dive his computer might start calling for deco while mine is still a long way out, does his dive become a deco dive because his extremely conservative computer says so or is it not a deco dive because my liberal one says it is not?
Following your computer blindly is not always the best course of action.

 

[Dody]

Thanks for posting your experience.
As far as i understand the stop at 20m was a deep stop.
The stops at 12 and 5m were stops not told by the computer, but you just did because you had air left. Right?

What kind of computer are you using?
And can you upload the dive profile?

Lots of advice was already given.

Most important (in my opinion) and something to improve on:
1. Dont use the tank at 5m in your gas calculation.
2. Never trust the DM.
3. 40m is no joke. I believe you, that you didnt feel narked. But you were 100%.
Dont ride the NDl at that depth. (tbh never ride the ndl).
4. Use your worst case sac and round it up for gas calculation. For example i have between 10l to 12l/min and just in rare cases it goes up to 14.
So i use 15 in mingas calculations. (doubled up to 30l/min in an emergency)

Then ofc dont do fin pivot and go to the deepest point first. But i think you already learned this one.

All stops were dictated by the computer. All 2 minutes stop. But for the 5 meters one, we decided to do 5 minutes instead of 2 just because this is what we always do.
I have an Aqualung 750. Used to have a 300 before. I will upload the dive profile on tuesday when I return from my week-end.
Good summary of the good advice I received today. I will add the pony and using the BCD to ascend (must overcome my concern to become a Polaris rocket).
I was reading my watch user’s manual of my computer and I feel puzzled. You can use different algorithms with very different results. For example, SSI NDL at 40 meters is 5 min but US navy is 10. And it is still 10 at 40.5 meters. So much for consistency.

 

[Dody]

All stops were dictated by the computer. All 2 minutes stop. But for the 5 meters one, we decided to do 5 minutes instead of 2 just because this is what we always do.
I have an Aqualung 750. Used to have a 300 before. I will upload the dive profile on tuesday when I return from my week-end.
Good summary of the good advice I received today. I will add the pony and using the BCD to ascend (must overcome my concern to become a Polaris rocket).
I was reading my watch user’s manual of my computer and I feel puzzled. You can use different algorithms with very different results. For example, SSI NDL at 40 meters is 5 min but US navy is 10. And it is still 10 at 40.5 meters. So much for consistency.

US navy NDL is in fact 8 minutes at 40,5. But it is only at 58 m that it is 5.

 

[David Novo]

I will add the pony and using the BCD to ascend (must overcome my concern to become a Polaris rocket).

Use your BCD to be as close to neutrally buoyant as possible. Change your breathing pattern to ascend or descend (do not hold your breath while ascending).

I was reading my watch user’s manual of my computer and I feel puzzled. You can use different algorithms with very different results. For example, SSI NDL at 40 meters is 5 min but US navy is 10. And it is still 10 at 40.5 meters. So much for consistency.

If you are doing dives to 40m with it, you better become familiar of how your dive computer works.

There are different decompression models based on different theories. Read "Deco for Divers" from Mark Powell if you want to understand it better.

 

[Blackcrusader]

My Cressi also had a deep safety stop as an option that comes turned on when first using the computer. It’s stated in the manual that it was an option that some diving philosophies prefer, so I turned it off.

However, this was after a couple of deep dives with an instructor that did what I now know from SB as Pyle stops, where we stopped halfway up the anchor line for 2 minutes (40-50 ft) and then again at 15 feet for the second safety stop,

Thanks I did ask was he doing Pyle stops but it likely was not understood by Dody.

 

[Blackcrusader]

I was reading my watch user’s manual of my computer and I feel puzzled. You can use different algorithms with very different results. For example, SSI NDL at 40 meters is 5 min but US navy is 10. And it is still 10 at 40.5 meters. So much for consistency.

Do not change the settings from the default atm. If you feel puzzled then you cannot understand why there are differences. You are perhaps not ready for this yet without further training. The reason dive computers for recreational divers have more conservative settings is to keep them safe. Learn to dive to your computer as it is. I think you are trying to be a good diver but are trying to squeeze in the experiences of others which are not your own. You are trying to rush things and I can say when I was a new dive like you I did the same thing. Take all the advice you can here as it is free. SB is like your I can ask questions and get answers. Sometimes the answers we will not like. There as no SB back in 1986 so I only had the BSAC club instructors, dive leaders and experienced divers I could ask at training sessions or at the club or on the boat.

I never rely on a DM the DM is a guide I have to dive to my own settings and monitor my own air and depth. I would take issue more with your DM that he allowed you to get into an unsafe dive situation as you are on a training dive and your first deep dive to 40m which you exceeded. You think your DM is a good diver because he is a DM. You think your instructor is a good instructor but where was your instructor on your training dive? Sipping a latte back at surface? Not with you on the dive that we know.

Did you tell your instructor you exceeded 40m depth and probably exceeded NDL when you struggled to ascend. If you were struggling to ascend why didn't your DM assist by putting some air into your BCD and giving you an assisted ascent? Reviewing the dive log with your instructor would be a good thing to do.

 

[Dody]

Thanks I did ask was he doing Pyle stops but it likely was not understood by the dody.

Dody I wrote that you did not use your BCD for its intended purpose. As this was your first dive to 40m if you did not add air you could be struggling to ascend simply because you did not have enough air in your BCD and were negatively buoyant which is why you were swimming at 45 degrees finning away to ascend. Maybe no down current maybe you just did not adjust your BCD pressure to make yourself neutrally buoyant. Narced and cannot think the situation clearly. You also wrote you did not add air when you should have and tried to swim up. As others noted you should be able to use your lungs to adjust depth if you are neutrally buoyant at any depth and adjusting amount of air in your BCD is part of that process.

As I wrote you waste a lot of air especially at depth when you swim and your thinking of 11l/min x 5 is so incorrect. 15l/m x 5 depth pressures x 2 for emergency x 2 to assist diver in distress out of air... so getting to that pony bottle that is nowhere near you won't save you.

Here I am at near 40m with a dive buddy from Taiwan he is CMAS 3 star and the DM guide I have done hundreds of dives with. The DM took my go pro to film us on the dive. I'm the fat bloke in the blue shorts with the snorkel. As you can see I can exhale to descend and when I inhale I an stop the descent using my lungs. Now for ascending again but one must be careful not to use full breath in and over expand your lungs. We got to depth quite quickly so we had the time to look at some gorgeous fans with a max depth of 40m. We did not exceed 40m and we did not exceed NDL and we started our ascent with 3 mins to NDL. Just because you plan max depth 40m does not mean you have to reach 40m anywhere between 35m to 40m is fine. As others wrote want to see a bigger number on your dive computer switch to feet. All of us are experienced divers. Like you I am a recreational diver.

Note that the DM is slightly below or at same depth with us. You can hear he has a rattle that is him advising us his dive computer is at 5 minutes to NDL so we have another 2 mins then ascend. The difference between your dive and mine, we got to the site in a time that allowed us to see what we wanted to see and not be scraping 1m to NDL. We did not exceed 40m in fact the deepest diver was the DM at 39m. We had a nice controlled slow ascent back to around 20m. You could say we rode the NDL where we do not let the NDL get to less than 2 minutes to any depth as we ascend where the wall opens up into a nice plateau that has lots of things to see on a very gentle slope so the edge of the wall up the slope goes from 20m to around 8m depth. Great place to bring OW divers only they cant go see the gorgonian coral fans.

We all use our BCD and breathing to control depth. We are swimming into a very slight current. All three divers are paying attention to their own DC and we planned the dive and dived the plan. Yes we are on AL 80 tanks with 210 bar start and if an emergency occurred as we are not in deco we need 4 mins or more to get to the surface without a safety stop.

I was neutrally buoyant at 40 meters. If there is one thing I do correctly is being neutrally buoyant at all times except ascending or descending fast. So I had air in my bcd as I added air regularly during the descent. I also constantly use respiration techniques to move up or down a few meters or fine-tune my buoyancy control. That’s how my SAC went down from over 20 to 11 in average. 20% of the time, I am not even finning just hovering.
For the rest, I got it.