An age-old question: ways to 60m.

[old frogman]

Do I understand correctly that after TDI ANDP, there are two main ways to go deeper, down to 60 meters?

1. OC Trimix – Take a Trimix course (around 5 days), and then you're good to go. But each dive will cost you an extra ~$250 just for the helium.
2. CCR – Buy a CCR unit and complete MOD1, Helitrox, and Mixed Gas training (about 15 days total, spread out over time). After that, you're free to dive, and each dive costs around $50 for consumables.

Is that correct?

P.S.
I know about Extended range but I am not fill comfortable on air down to 50m....

If your depth limit is 60 metres. Another option, which is perhaps outside the DIR modernist mindset, is to go semi-closed circuit rebreather (constant mass flow gas delivery to counterlung). Some navies still use them because they are purely mechanical, simple, reliable and no electronics or sensors to fail. Also they can be deployed into action very quickly (in comparison to ECCR). So reliable navy divers use them without the need for OC bailout gas. They reduce the helium cost by a factor of 4 (compared to OC). Navies dive them on nitrox down to 54 metres. With the addition of some helium in the mix you can dive them to 60 metres. Some notable military models are as follows:
US Westinghouse MK 6 capable to 60 metres with helium in the mix. Predecessor of UBA MK 15/16
US Viper SC
French La Spirotechnique CRABE.
Italian OMG Azimuth
German Draeger 5400/Dolphin

Some SCR rebreathers were available on the civilian market in the late 1990s however they fell out of favour due to the ego of technical divers who wanted the deepest rebreather available, even though many never took them deep.

However, if you want to go to 60 metres you can pick up a second hand serviceable ECCR send it to an appropriate diving engineering workshop and have it converted to SCR. The main gas delivery to the counterlung components are as follows: 1st stage valve, constant mass flow valve and manual addition valve. The adjustable overpressure valve is required for the counterlung to vent off excess exhaled gas. Fit it with 2 x 5 ltrs gas cylinders with your choice of premixed gas.

For 60 metres you need a jet that delivers about 20 ltrs/min flow.

Interested to know if anyone has successfully gone down this path.

I am sure this will severely challenge the DIR mindset.

 

[Eric Sedletzky]

There is nothing wrong with people telling others how they are diving and sharing their experiences.
You have your agenda to push a certain way to do deep dives. That's fine that is your perspective.
Trimix diving might be fine for those who can afford on on OC.

The OP isnt really doing enough diving to warrant the cost of CCR.

For me all I need is enough gas whatever the mix is. Yes all of us are numpties for not following your advice on how to do deep dives. Of course we can just ignore posts where people hyperventilate and are lacking in social graces no matter how good their intention is.
You start to sound like a cult member. Do it this way or not at all.


View attachment 906520

WTF!!!!!!!

 

[Boarderguy]

For farks sakes. There are 21 pages here with multiple instances of numpties advocating that the OP does deep air. And you were the first to jump in on it on post 2 or 3.

And clean up your back yard.

He's not a new diver. Someone who is getting into the tech game and looking to expand their range is new to you? Ffs you're dense. Deep air may not be your jam, but it isn't the devil you and your ilk make it out to be.

I don't need to clean it up, that's what the kids are for.

 

[lermontov]

Jeez, look at my sac.

It gets bigger as I age.

thats your prostate

 

[lermontov]

So you think new divers are diving to 60m?

there will be more if they follow the advice of those advocating it as no big deal

 

[greatwhite1]

There is nothing wrong with people telling others how they are diving and sharing their experiences.
You have your agenda to push a certain way to do deep dives. That's fine that is your perspective.
Trimix diving might be fine for those who can afford it on OC.

The OP isnt really doing enough diving to warrant the cost of CCR.

For me all I need is enough gas whatever the mix is. Yes all of us are numpties for not following your advice on how to do deep dives. Of course we can just ignore posts where people hyperventilate and are lacking in social graces no matter how good their intention is.
You start to sound like a cult member. Do it this way or not at all.


View attachment 906520

All you need is enough gas for the dive? Now, that's the most stupid comment I have ever read.

 

[iliketopetsharks]

For me all I need is enough gas whatever the mix is.

LOL
Oxygen toxicity is just fearmongering, you'll be fine diving 100% O2 to 40 meters. Trust me bro.
/s

 

[iho]

If your depth limit is 60 metres. Another option, which is perhaps outside the DIR modernist mindset, is to go semi-closed circuit rebreather (constant mass flow gas delivery to counterlung). Some navies still use them because they are purely mechanical, simple, reliable and no electronics or sensors to fail. Also they can be deployed into action very quickly (in comparison to ECCR). So reliable navy divers use them without the need for OC bailout gas. They reduce the helium cost by a factor of 4 (compared to OC). Navies dive them on nitrox down to 54 metres. With the addition of some helium in the mix you can dive them to 60 metres. Some notable military models are as follows:
US Westinghouse MK 6 capable to 60 metres with helium in the mix. Predecessor of UBA MK 15/16
US Viper SC
French La Spirotechnique CRABE.
Italian OMG Azimuth
German Draeger 5400/Dolphin

Some SCR rebreathers were available on the civilian market in the late 1990s however they fell out of favour due to the ego of technical divers who wanted the deepest rebreather available, even though many never took them deep.

However, if you want to go to 60 metres you can pick up a second hand serviceable ECCR send it to an appropriate diving engineering workshop and have it converted to SCR. The main gas delivery to the counterlung components are as follows: 1st stage valve, constant mass flow valve and manual addition valve. The adjustable overpressure valve is required for the counterlung to vent off excess exhaled gas. Fit it with 2 x 5 ltrs gas cylinders with your choice of premixed gas.

For 60 metres you need a jet that delivers about 20 ltrs/min flow.

Interested to know if anyone has successfully gone down this path.

I am sure this will severely challenge the DIR mindset.

Might make sense to convert mCCR to that? Like Triton? Should be easier...

 

[greatwhite1]

LOL
Oxygen toxicity is just fearmongering, you'll be fine diving 100% O2 to 40 meters. Trust me bro.
/s

I can smell his waffles burning again!

 

[Celt]

Well, a post without the usual accusations here, bravo!

As an old diver, I remember the times when practically only air and thus air deep was the norm for sport divers. There were also accidents because divers struggled with the demands in combination with impairments associated with air deep. Nowadays, divers usually dive much shallower with air, so we older divers think there shouldn't be many accidents anymore. Unfortunately, that's not the case, and there must be reasons for that.
Speleo, as an instructor, you might be able to tell me how you prepare the students to deal with the requirements of dense air, CO2, high pPO2, and narcosis due to CO2, O2, and N2.
Or are these issues considered to be only avoidable through technology?
So what do you do to train the human body and mind for this?

Asking this on SB unfortunately rarely gets a response because the people with experience of deep air are personally attacked. A routine that works for me is to start the dive in the water with no mask breathing slowly and deeply till it’s about 6 BPM. I clear my mask and drop quickly, 2 to 3 minutes to 60m, I squint my eyes to kick in my night vision and get used to the loss of light. As the wreck appears I slow my descent and take a moment to relax and check time, depth and gas. The main side affect for me deep is tunnel vision so I move slowly and deliberately searching both sides. Dealing with gas density. Heavy work deep on air is very dangerous and can only be done in short spurt of 1 to 2 minutes, if you get out of breath you can not get it back without halving your depth, you will pass out and drown. When salvaging copper and brass we would clear an ingot, stop and bring our breathing under control and then put it in the cradle. Not for all the tea in china would I work deep on air at this stage but adults are adults and they make their own decisions. Maybe the reward is worth it for them. You might like to read “ The Oxygen Advantage by Patrick McKeown “