Are dive computers making bad divers?

[Akimbo]

A one compartment decompression computer!

You have just described the perfect decompression computer for saturation diving! Only the slowest tissues drive the calculations.

Seriously, this meter probably "emulates" several of the faster tissue compartments that drive most of the recreational dives even today. It is really sort of clever, build a prototype and run a bunch of small chamber tests that, when averaged, drive the graphics design of the custom gauge face. No batteries or software upgrades required.

Considering that the alternative was to have one of these on the boat and dive with an umbilical, the SOS meter was not a bad option:

Here's a good article if anyone is interested.

Vintagescubadiving.com

vintagescubadiving.com

 

[BlueTrin]

@Akimbo that’s a really cool article.

 

[dmaziuk]

You have just described the perfect decompression computer for saturation diving! Only the slowest tissues drive the calculations.

Assuming the safe ascent rate is known to take care of the fastest TC, and you don't stay down long enough to load the slow ones, you should be able to get away with only 2-3 TCs in your model. It may have higher DCS risk for sub-optimal profiles, but as bend-o-matic demonstrated, on average it could do just fine.

 

[Akimbo]

It may have higher DCS risk for sub-optimal profiles, but as bend-o-matic demonstrated, on average it could do just fine.

I forget how many tissues were routinely calculated in that era for Navy tables, but it was nothing like today. Even the John Scott Haldane's original tables were calculated based on educated guesses at a handful of different tissue rates and adjusted by the results of chamber tests.

Some of the theoretical work on very slow tissues was done by the US Navy starting in the late 1930s, which set the foundation for Doctors George Bond and Walter Mazzone to calculate saturation decompression tables for Project Genesis. All the calculations were done by Dr Mazzone with a slide rule and paper.

Dr Albert A. Bühlmann's work on the tables for Hannes Keller's 1,000' Dive in 1960, and test dives leading up to it, was the basis for the Bühlmann decompression algorithms used by most computers today. The naming convention of algorithms, for example, ZH-L16, is based on Zürich (ZH), limits (L) and the number of tissue compartments or M-value sets used.

The SOS meter was more of a brute force solution. Fashion a pressure gauge face that emulates the tables that work and call it good. Very few divers in the 1960s even knew tissue compartments existed, which tables were based on, except a few that worked at navy experimental diving units in the US and Europe.

 

[wetb4igetinthewater]

You have just described the perfect decompression computer for saturation diving! Only the slowest tissues drive the calculations.

Seriously, this meter probably "emulates" several of the faster tissue compartments that drive most of the recreational dives even today. It is really sort of clever, build a prototype and run a bunch of small chamber tests that, when averaged, drive the graphics design of the custom gauge face. No batteries or software upgrades required.

Considering that the alternative was to have one of these on the boat and dive with an umbilical, the SOS meter was not a bad option:

View attachment 731455​

Here's a good article if anyone is interested.

Vintagescubadiving.com

vintagescubadiving.com

I would like to buy one of those for my future dive center as a historical item and conversation piece. One of the things I plan to have is movie/social nights where we watch a dive related movie, chat to get to know one another, and be able to talk about the history of diving.
On a separate note, when it comes to embedded computing, the capabilities of microcontrollers that are used in dive computers today has made similar leaps as smartphones, tablets, desktop/notebook computers. I don't know what microcontroller is used in Shearwaters, but the Deep 6 Excursion does use a 32-bit TI arm chip that is quite capable. Also what has improved by leaps is the development tools, knowledge being shared on the internet, and expertise of firmware developers.

The dev environments of say the Keil compiler for the 8051, as good as it was for the 1990s, is absolutely nothing to what is available to developers today for various ARM chips.

People's experiences of more than 10 years ago simply isn't relevant to the latest offerings.

 

[Akimbo]

I would like to buy one of those for my future dive center as a historical item

They come up on eBay all the time.

Scubapro Vintage Decompression Meter Scuba Pro Diving Dive Gauge | eBay

Find many great new & used options and get the best deals for Scubapro Vintage Decompression Meter Scuba Pro Diving Dive Gauge at the best online prices at eBay! Free shipping for many products!

www.ebay.com

The originals came with plastic bodies and the stainless came along in the late 1960s.

 

[wetb4igetinthewater]

They come up on eBay all the time.

Scubapro Vintage Decompression Meter Scuba Pro Diving Dive Gauge | eBay

Find many great new & used options and get the best deals for Scubapro Vintage Decompression Meter Scuba Pro Diving Dive Gauge at the best online prices at eBay! Free shipping for many products!

www.ebay.com

The originals came with plastic bodies and the stainless came along in the late 1960s.

got my eye on one in good condition right now

 

[Akimbo]

got my eye on one in good condition right now

I haven't thought of this until now but there is a chance it will still actually work. It would be interesting to wear one next to your PDC and compare them. I don't think I have ever seen anyone try that.

 

[wetb4igetinthewater]

I haven't thought of this until now but there is a chance it will still actually work. It would be interesting to wear one next to your PDC and compare them. I don't think I have ever seen anyone try that.

Does it have a CCR mode?

 

[Akimbo]

Does it have a CCR mode?

Sure, at 21% N2O2.