Redundancy- Waste of time?

Ben Field

Ben Field

All IMVHO obviously...
Possibly flammable question, sorry.

When I first got a rebreather I followed (like a sheep) the majority and got BOV, hoses to add gases, then added HUD when they appeared and so on.

Subsequently sold my rebreather and started from scratch, currently have just a single combined PPO2/computer, no SPG's, no offboard addition capbility, no HUD, no BOV. Just Unit on my back and bailout at my side, if it breaks in any minor way bailout and fix it back on the beach.

(Caveat- This fits my diving (open water, wreck etc) I understand if you are some cave nut then keeping on the loop is more of a priority so I am not talking about what I would term as Expedition level diving.)

I see alot of units now come with Everything, multiple monitors, CO2 this and that, backup everything, some even have multiple HUD's. All of this "bling" is very clever.

Now, call me a Luddite if you must (I'm not, I love tech) but have we obscured the purpose in adding functionality that for 99% of diving is entirely superfluous?
IIRC, the point was to go SCUBA diving.

Take the example of BOV's and CO2 monitors, good things and ubiquitous but primarily they serve to protect against one problem*, CO2 breakthrough, something that by observation only (no hard evidence) isn't very common... yet we are all excepting approximately £1000 increase in unit cost to cover this contingency.
(* I realise proper CO2 monitoring would protect against retention and overwork and would be "a good thing" this ^ is just an example, it does have flaws :-)

Ditto HUD's and secondary handsets, unless you add 3 more sensors with each they're essentially just two displays for the same data, short of having a whole secondary loop they don't protect the user from much while at the same time contributing to data overload. At the same time these extra features require extra care, extra battery's, extra preparation and servicing and without doubt cause extra concern if they don't behave.

Would anyone dare speculate on the difference in Actual safety compared to Perceived safety of having a very simple rebreather in contrast to a Fully Featured, bells and Whistles unit?
Is Redundancy misleading people at the consumer/recreational end of the market?
Are we as a group just layering solutions over issues and problems that might not be real issues?

Your thoughts please :-)
 
As ever, Ewan Rowell has this covered on the Inspiration List circa 2001...

"Poor weather on Friday, but I was gagging to get my much-improved
Inspiration wet for the first dive of the season, so got onto the Maid
Maggie a few hours early to prepare my unit while I waited for my new buddy
to turn up.

They'd teamed me up with some Inspiration user from Congleton in
Cheshire, who'd just moved down to Plymouth, so I was looking forward to
giving him the benefit of my experience.

The Inspiration calibrated perfectly as usual - 1.3 bar and steady as a
rock - those Zinc-Air cells certainly proving a wise buy.

All at once the skies cleared, the sun came out, the wind died, the water
turned calm and a noisy red motorbike pulled up on the quay.

The rider introduced himself as "Rich" and was obviously impressed at my
head-up display, oxygen and diluent mixing blocks allowing me to mix from
any of the six back-mounted cylinders, triple-redundant deco-computers I'd
plumbed in, and the quadruple-bladder wings I'd added.

"Do you really need all that stuff?" he asked.

"Listen sonny", I replied "I've been diving since you were in short
trousers, and this unit's been to the bottom of Stoney Cove on more than
one occasion. A basic unit like you've got may be OK for your kind of
diving, but when you start doing serious stuff, you'll need to improve on it."

We were first in the water.
A number of the group helped me to the side of the boat, but in their
enthusiasm accidentally pushed me over it.

It took only a few minutes to satisfy myself which of the three diluent
buttons on the left c/l was plumbed correctly for the target depth, and
which wing bladders were hooked up, but by that time I'd hit the wreck
(rather hard). As soon as I was sorted, I looked up and, seeing my buddy,
gave him the OK sign. I thought he was having a minor O2 hit, because he
was holding his stomach and seemed to be shaking uncontrollably, but he
soon gave me an OK sign and assured me he was fine, so we headed off. No
spikes - the handsets were reading a steady 1.3.

A couple of minutes later I noticed a gurgling sound and my WOB started to
increase.
I'm not sure where the leak started - the shock of hitting the wreck must
have loosened off one or more of my manual add buttons, or possibly a lead
from one of my computers may have caught on something.
I turned to indicate the problem to Rich.
He gave a signal back that I didn't recognise. Obviously one that's popular
up Manchester way.
At that moment I felt a wave of CO2 hit me and, sure enough, this was
confirmed by the klaxons and flashing lights of my CO2 alarm.
This quickly drained the master, which started giving a low battery alarm.
The cells were fine though - all steady on 1.3.

One of the great strengths of my system is that I have 17 different bailout
options and can choose whichever one is most suitable for the depth and
bailout scenario, however, I have to admit that I found myself a tad
stressed at this point so possibly selected a couple that weren't quite
perfect before switching the integrated mouthpiece to OC and breathing easy.

It seemed best to turn the dive as I no longer felt able to properly
nursemaid Rich. I signalled my intentions.
He made another of those strange signs in reply.

I'd noticed, after adding twin 12 litre offboard cylinders to the side of
the case, that my Buddy wing suddenly didn't have enough lift, but now even
four 80kg bladders didn't seem that much better. I had to pull myself up
the shot for the first ten metres until the expanding gas in the
counterlungs took over. Rich seemed to be having another of those oxygen
hits, and I felt bad about having to leave him as my buoyancy ran out of
control.

I was travelling quite fast when I hit the surface and would have dumped
some gas on the way, but my arms were pinned hard between full counterlungs
and wings, so was forced to just bob and wait to be picked up.

As I lost consciousness, I remembered I was using 10/50 heliair.

I'm told that Rich and the lads on the boat tried to pull me in using the
anchor (I suppose I'm rather heavy in full kit), which holed my scrubber
cannister. When the seawater hit the Lithium Hydroxide, there was an
almighty explosion, which lifted me into the boat, blew the mouthpiece away
from my face, and sprayed everyone else with frothy and very caustic liquid.

By the time I came conscious, they had all jumped into the water and I was
sitting on the deck alone.
My handsets were both reading a healthy 1.3.

All things considered, a successful dive, but maybe one or two more mods
required.
Only the correct attitude and a comprehensive training had averted a nasty
incident - ten quid well spent IMHO.

... and yet another dive without a single cell error, which is encouraging. "
 
I love the story. Too funny! :-)

As for tarting up the RB, in every sport in which you purchase equipment, there are those who buy "just what is needed to accomplish the task" and those who tart the thing up to the hilt. Whether fishing, fishing boats, motorcycles... you name it and you can probably cite examples and/or friends who have the minimal equipment and those who spend all their cash on "extras".

I think the RB simply falls into the same area. Some dive the unit pretty much "as purchased" and others can't stop adding bells and whistles. It's just the nature of the beast, IMO.
 
There may be an element of fashion but unlike wearing a silly jacket to fish in rebreather parts are typically chosen for some kind of functional or safety reason.
As I was alluding earlier, some of these accessories are possible causing excessive complexity and increasing the risk on simple dives- your fishing jacket is unlikely to make you more likely to get biten by a trout :-)
 
Ben, another flammable question but linked to your points right at the end of you OP. Is the equipment making up for the lack of consistent, high quality training?

Regards
 
I like the simple life, I'm quite happy diving a single 3 cell PPO2 monitor as the rebreather instrumentation on a mCCR where I can carry enough off board bail out to surface using my non plumbed in computer.
Although for deeper diving I am very tempted to run 4 cells, 3 to a hardwired shearwater Nerd and the 4th to a single cell Kiss PPO2 meter.
However I also enjoy diving the hCCR, rEvo 3 cells to the shearwater and a 4th cell to the 'dream.
 
For me the bits I've added were functional, making the unit or I a little more comfortable.

HUD - well, it came with the breather. But now I've had the use of one I think laziness in dragging paddles out would ensure I had one on any other units. If the controller/display was also my dive computer and strapped to my arm, not so bad - but lazy Starfish likes the HUD.

Case - again, it was cheaper to make a new case than it was to replace the two pony bottles I had with the exact ones to fit in the yellow box. And bashing around reefs chasing dinner in the surge I wanted something that could take a pounding. So stainless was the answer.

BOV - FUD decision. Instructor says get one before we do MOD2. Fine, got one at a good price. I now find (just coz it's easier) I will bail out for sanity breaths if I get any funny feelings whereas before on the DSV I would have stayed on the loop and kept an eye on whether funny feelings got worse. A simulated bailout at 50m and an idea of just how fast I go through gas if I start whaling on the reg in a CO2 hit has me very pleased with this purchase.

More purchases/improvements down the track? I will probably look at a temp stick conversion and probably a split sorb canister too, just coz I hate chucking kitty litter that's only half used.

All that said, I also have plans to make a TP2000 or variation thereof and that will have nothing but a button SPG on the first stage. Maybe a single cell in the loop connected to my NiTek if I can be bothered.
 
Is the question really about redundancy? I dive my rig with BO, so I have a redundant air source, but I have removed some of the bits from my setup that i feel I can do without.

After about one hundred hours with a BOV, I am now happily without. Of all the "safety items", I agonized over this one the most. For sure it was the most finicky bit of kit. Mostly it worked, but it required a fair bit of tlc in addition to the many failure points. Additionally, i do not find it easy to swap tanks by plug and ply via the QC 6, this is a two handed operation. I a m convinced to not have a reg in my mouth that I cannot breathe from. So BO gas routing is much easier.

I tried a stand. Great while sitting on the boat, glad to be shot of it. It felt like I was swimming with a chair on my back.

I ditched the spg's. I was running button gauges, but only the wee ones fit as I want them to, and they are unreliable. S o no gauges.

I am happy with three cells. I replace one every six months. At that time I run them all through a cell checker. I run them up to 100 percent O2 before dives.

One Shearwater connected via Fisher and a bottom timer. Bigger dives get bailout tables taped to the. Controller.

I have a HUD and like it. My unit is now a ECCR, after well over 100 hours as an MCCR, the HUD is in a better position now without the BOV, if it changes colour, I ****ed up.

For bigger dives I am now using a small redundant O2 bottle. This matches my suit bottle on the other side. It is plumbed in to the spare MAV on the exhale lung on my Meg.

My left side BO tank has a five foot hose to the second stage. I do not bungy it to me as I found this to be a nuesence with the otscl.

Now when I jump in, I am quick to be ready. I am carefully to have my BO reg to hand. I never am plumbed to a gas I cannot breath, and I find it easy to get out.

All I see the folks who insist on four or more cells getting for their troubles is more cell failures. They remind me of my first dive partner who festooned himself with second stages believing he would be safer.

The ADV on the Meg works well and I use the slider shut off to isolate the dil for most of the dive.

I have a drawer full of bits I have tried out. For me I am finding that less is more.

Peter
 
GLOC said:
Ben, another flammable question but linked to your points right at the end of you OP. Is the equipment making up for the lack of consistent, high quality training?

Regards
Click to expand...

No

Most trainig is prety good good but lacks focus in key areas because it defaults to the units design feetures rather than how a CCR (any CCR) should be dived

However all the bells and whistles do encourage unit dependancy in divers which is something the current training programs dont properly adress.

Saying "we told the student to always know his PP02" is IMHO a total cop out if reliance is on the unit to tell the diver whats going on.

ATB

Mark
 
Ben Field said:
Possibly flammable question, sorry.

When I first got a rebreather I followed (like a sheep) the majority and got BOV, hoses to add gases, then added HUD when they appeared and so on.

Subsequently sold my rebreather and started from scratch, currently have just a single combined PPO2/computer, no SPG's, no offboard addition capbility, no HUD, no BOV. Just Unit on my back and bailout at my side, if it breaks in any minor way bailout and fix it back on the beach.

(Caveat- This fits my diving (open water, wreck etc) I understand if you are some cave nut then keeping on the loop is more of a priority so I am not talking about what I would term as Expedition level diving.)

I see alot of units now come with Everything, multiple monitors, CO2 this and that, backup everything, some even have multiple HUD's. All of this "bling" is very clever.

Now, call me a Luddite if you must (I'm not, I love tech) but have we obscured the purpose in adding functionality that for 99% of diving is entirely superfluous?
IIRC, the point was to go SCUBA diving.

Take the example of BOV's and CO2 monitors, good things and ubiquitous but primarily they serve to protect against one problem*, CO2 breakthrough, something that by observation only (no hard evidence) isn't very common... yet we are all excepting approximately £1000 increase in unit cost to cover this contingency.
(* I realise proper CO2 monitoring would protect against retention and overwork and would be "a good thing" this ^ is just an example, it does have flaws :-)

Ditto HUD's and secondary handsets, unless you add 3 more sensors with each they're essentially just two displays for the same data, short of having a whole secondary loop they don't protect the user from much while at the same time contributing to data overload. At the same time these extra features require extra care, extra battery's, extra preparation and servicing and without doubt cause extra concern if they don't behave.

Would anyone dare speculate on the difference in Actual safety compared to Perceived safety of having a very simple rebreather in contrast to a Fully Featured, bells and Whistles unit?
Is Redundancy misleading people at the consumer/recreational end of the market?
Are we as a group just layering solutions over issues and problems that might not be real issues?

Your thoughts please :-)
Click to expand...



I beleive MCCR keeps us honest as CCR divers (I have gone back to diving a needle valve on my JJ running low set point)

I beleive three cells propely managed is more than enough to do a dive

I beleive two indipendedt PP02 displays showing each cells performance is all I need to control a CCR properly and safley

I beleive three large bailout cylinders is the maximum acceptable task loading for deep dives without surface suport

I beleive C02 hits are a valid concern and a BOV to a large off board gas sorce is the only viable responce to a full on C02 hit

I beleive HUDs are the only safe way to dive a CCR

I beleive the fewer electronics on a CCR the less likley it is to do something odd or just fail

I beleive the 10" spike on the stearing wheel is the best way to keep the driver alert at all times.




I am undecided about C02 monitors mainly because I dont think we have built a good one yet.


ATB

Mark
 
Thank you guys. Following the "simple is best" approach I have now removed my BOV, back to a DSV and emptied all my bailouts - they just add complications. I'm looking forward to my simple unencumbered 60m dive on Sunday without all the crap hanging off me. Ewan will be there, I will remind him of his dive report from way back when and offer to carry one or more of his bailouts if anything goes wrong!

:720icon:
 
Yes bailout is seriously over rated.

In over 1500 hours underwater on CCR i have only needed bailout on 3 dives so max 9 hours worth of diving required bailout out of 1500


OK if we are being pedantic id have died the fist time but hay statisticly Bailout is over rater :wave2:
 
What I like about these type of posts are that they are thought provoking and lead to some good discussions.
I come in the less is better camp also cheaper:-)
Andy
 
I'm in agreement with most everything being listed but not doing away with the BOV. Having had a CO2 hit it was good to know that all I needed to do was twist a knob and not have to take a reg. out of my mouth and insert a new one. Now most of my dives are 200 ft. are less so I am able to keep a breathable gas plugged into the BOV from surface to bottom without having to reconnect gases underwater.


Sent from my iPad using Tapatalk
 
Mark Chase said:
I beleive two indipendedt PP02 displays showing each cells performance is all I need to control a CCR properly and safley

I beleive HUDs are the only safe way to dive a CCR
Click to expand...

Mark, concur with you in all the other points, but not sure about these two quoted above. I dive a Kiss with a hardwired Predator.

Predator screen is highly visible and either if I am being towed by a dpv or finning I keep it almost always at sight. Besides, it flashes and make color changes if something goes wrong. Why should I need a HUD or secondary displays?
 
I feel guilty for doing this but I am still in awe of this unit for the amount of problems that have been solved, there are details in the details that even I had not thought of...

 
As Steve McQueen said to Dustin Hoffman when making Papillon, "throw all that shit out, man, keep it simple".

A robust unit with simple electronics beats the hell out of all the flashy lights and "features". Diving a stock Mk15 was an absolute joy. Switch it on, dive, green light good, red light bad. No bells, no whistles, no latest technology bullshit. I rue the day I replaced the Rev G pod with a HH and ended up with a "sophisticated" unit. The simplicity was fantastic, designed for people that wanted to think about the task rather than the unit.

Everyone should be made to dive a homebuild as a pre req to mod1. Teaches you what you need and not what you want.

I like having a redundant display but that might be from diving a Hammerhead for the last five years. It teaches you the value of a reliable, passive secondary...

Sent from my GT-I9300 using Tapatalk
 
Mark Chase said:
I beleive MCCR keeps us honest as CCR divers (I have gone back to diving a needle valve on my JJ running low set point)

I beleive three cells propely managed is more than enough to do a dive

I beleive two indipendedt PP02 displays showing each cells performance is all I need to control a CCR properly and safley

I beleive three large bailout cylinders is the maximum acceptable task loading for deep dives without surface suport

I beleive C02 hits are a valid concern and a BOV to a large off board gas sorce is the only viable responce to a full on C02 hit

I beleive HUDs are the only safe way to dive a CCR

I beleive the fewer electronics on a CCR the less likley it is to do something odd or just fail

I beleive the 10" spike on the stearing wheel is the best way to keep the driver alert at all times.




I am undecided about C02 monitors mainly because I dont think we have built a good one yet.


ATB

Mark
Click to expand...

Mark,

What needle valve are you running, where have you located it?


Sent from my iPhone using Tapatalk
 
garethingham said:
Mark,

What needle valve are you running, where have you located it?


Sent from my iPhone using Tapatalk
Click to expand...


I am using the Chris Kenedy (SP) one. Pelegan is fine as well but more expensive.


I simply replaced the JJs manual 02 inject with the needle valve.




ATB

Mark
 
Last edited:
andrespp said:
Mark, concur with you in all the other points, but not sure about these two quoted above. I dive a Kiss with a hardwired Predator.

Predator screen is highly visible and either if I am being towed by a dpv or finning I keep it almost always at sight. Besides, it flashes and make color changes if something goes wrong. Why should I need a HUD or secondary displays?
Click to expand...


If you have amazing hand set diciplin then your fine but for me I need my warnings right in front of my face.

I had a red flash on my HUD once and when I checked both hand sets they were both dead (inspo classic) since then I have always been a big HUD fan.

I have had several issues on my CCR in the last 10 years including hand set failures and several high and low PP02 events. ALL of them, were alerted to me by my HUD and not by the hand sets


When i dived a KISS I had a Persuit Hand set which was great but I also had the Shearwater HUD so if the hand set failed I could still stay on loop. Thats a big advantage on cave and deep dives and a HUD only cost me £600 which is cheep compaired to may other bits of dive kit.


ATB

Mark
 
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