I've been away from diving for a decade. What major discoveries have occurred in dive medicine and decompression theory since I left?

[ancient diver]

March 2012 published date! There's nothing more recent than this?

rx7diver

How about this one?

Manned validation of a US Navy Diving Manual, Revision 7, VVal-79 schedule for short bottom time, deep air decompression diving - PMC

The US Navy air decompression table was promulgated in 2008, and a revised version, calculated with the VVal-79 Thalmann algorithm, was promulgated in 2016. The Swedish Armed Forces conducted a laboratory dive trial using the 2008 air decompression ...

pmc.ncbi.nlm.nih.gov

 

[Johnoly]

I'm so confused,

This will help make it easy for you to understand ............

(it was a great presentation to be there)

 

[Wibble]

I think you pretty much "inherit" a particular decompression algorithm when you buy your dive computer. Different manufacturers use different algorithms.

Not nowadays. You know which algorithm you use (Buhlmann + GF) and you buy a computer that supports that. Even Suunto offers Buhlmann+GF on their "top of the range" computer as nobody wants their proprietary algorithms.

Since there aren't any agreed upon standards, its pretty much up to software programs and the dive computer manufacturer's decisions on algorithms. As usual, if you have a preference, caveat emptor.

It really is Buhlmann all the way now.

If you use tables instead of a computer, you inherit the algorithms used to develop the tables. NOAA, PADI, NAUI, CMAS

You train on tables, but you dive on computers and planners such as MultiDeco.

Actually nobody trains on tables any longer, unless it's a slide for exercises.

Nobody dives nor plans a dive using tables -- it's not the 1990s! Even bottom timers have gone out of fashion (except for some Ratio Deco laggards -- like Monty Python's People's Popular Front Of Judea)

Dives are planned using MultiDeco or the many other dive planners. You may write the dive plan on a slate for the first couple of dives after training, but you soon stop doing that and use the computerS--you'll have two computers for deeper dives, one as a backup. Practically speaking, you'd know your maximum dive time allowed and will dive using the computer's TTS (time to surface) calculation. (add the current runtime to the TTS for the projected dive time). When it gets close to your allowed time, you ascend for your deco.

It seems to me that a great deal of the discusion is driven by the technical diving, deep and planned decompression diving community which has gone to Buhlmann because you can tailor or optimise the model's gradient factors to fit your planned dive profile.

Actually, you're right. The very definition of technical diving is doing decompression or overhead diving.

The recreational NDL-ers may well still use tables to train. But they too all have computers to tell them when their NDL time is up; if they've not already ascended due to low gas or max dive time.


The ScubaBoard caveat... Of course some of you use tables all the time. Good on you. The rest of us use computers as they're good at those kinds of calculations (except it appears the new Apeks thing).

 

[flymolo]

I think tables and planners are synonymous when it comes to planning tech dives.

Plenty of people are still using pragmatic deco so I’m not sure why you think we’ve all gone to two shearwaters and just riding the computer up.

 

[NothingClever]

As usual, the USN used a different algorythm, tested with actual divers

I work with a DSO who’s headed up to the NEDU for a currency dive. I’m not going to share what his mix, depth, BT and TDT are…it’s insane.

 

[EE-JIT]

Not nowadays. You know which algorithm you use (Buhlmann + GF) and you buy a computer that supports that. Even Suunto offers Buhlmann+GF on their "top of the range" computer as nobody wants their proprietary algorithms.


It really is Buhlmann all the way now.


You train on tables, but you dive on computers and planners such as MultiDeco.

Actually nobody trains on tables any longer, unless it's a slide for exercises.

Nobody dives nor plans a dive using tables -- it's not the 1990s! Even bottom timers have gone out of fashion (except for some Ratio Deco laggards -- like Monty Python's People's Popular Front Of Judea)

Dives are planned using MultiDeco or the many other dive planners. You may write the dive plan on a slate for the first couple of dives after training, but you soon stop doing that and use the computerS--you'll have two computers for deeper dives, one as a backup. Practically speaking, you'd know your maximum dive time allowed and will dive using the computer's TTS (time to surface) calculation. (add the current runtime to the TTS for the projected dive time). When it gets close to your allowed time, you ascend for your deco.


Actually, you're right. The very definition of technical diving is doing decompression or overhead diving.

The recreational NDL-ers may well still use tables to train. But they too all have computers to tell them when their NDL time is up; if they've not already ascended due to low gas or max dive time.


The ScubaBoard caveat... Of course some of you use tables all the time. Good on you. The rest of us use computers as they're good at those kinds of calculations (except it appears the new Apeks thing).

if you dont do a plan, how do you do your Deco and gas planning? Is this a common approach?

 

[Blackcrusader]

if you dont do a plan, how do you do your Deco and gas planning? Is this a common approach?

I've not done a dive plan for NDL diving in the last ten years. In Maldives atm.. even on deep dives where the guides do deco of say 6 - 10 minutes it's up to the divers to decide to first. go deep, second, exceed NDL, third undersstand if they have enough gas.

Some of the divers won't do longer dive times due to their gas consumption but even on the deep dives and short deco I was still coming up with 100 bar on most dives of around 50 minutes. On several dives I was pushing low NDL on my perdix using 45/95 and I could hear quite a few divers DC's audio alerts.

Perdix AI of course has no Audio alert. I got one for my dive buddy to go along with his oceanic which he brings along as his backup.

He has a whole lot of learning to do on GF factors. GF99 Surf GF and other recent things the Perdix has in OC TEC mode.

 

[Edward3c]

See the thread title. Last thing I remember, before aforementioned ten year coma, was the study showing that Pyle stops tended to skew outcomes towards DCS. Now, I come back and nobody's using VPM-B or RGBM, and we're all doing Buhlmann again, so clearly something happened. Did we answer any big questions? Did we knock down any big hypotheses? Did we see any new pathologies? Why is Rubicon Foundation still down? Haven't they been down for a decade now? I'm so confused, so please confuse me better. Thanks.

On the medical front Immersion Pulmonary Oedema (IPO) has come to the fore.

 

[Wibble]

I think tables and planners are synonymous when it comes to planning tech dives.

Really?!? Technical divers using tables to plan their dives?

They would use the various planners such as MultiDeco, especially for planning different gases, runtimes, multi-level diving, optimising bailout timings, planning gas failures, CNS & POT optimisation, etc.

With rebreathers now dominating technical diving, especially deep diving, there's a lot more planning involved and tables simply don't cut the mustard. For example optimising bailout gases for speed of deco and keeping costs low, tables simply don't give you the gas loading to run a different ascent profile from that you'd have on your nitrox mixing machine, i..e. CCR fixed PPO2 setpoint switching to OC with variable PPO2 with depth.

Plenty of people are still using pragmatic deco so I’m not sure why you think we’ve all gone to two shearwaters and just riding the computer up.

Rule #1: If something's important, have a backup. If it's vital, have two backups (e.g. lights in caves).

It's very rare to see a technical diver with only one dive computer; it's not a nice prospect to run your deco with no dive computer because it died and there's no backup.

 

[flymolo]

Rule #1: If something's important, have a backup. If it's vital, have two backups (e.g. lights in caves).

It's very rare to see a technical diver with only one dive computer; it's not a nice prospect to run your deco with no dive computer because it died and there's no backup.

I run my planned deco and use my computer as a backup.

I do wear a simple wristwatch computer which I use as a stopwatch for timing my ascents and deco stops.

It’s just a different mindset