My O2ptima Configuration

n2diving · 13th February 2007, 17:15

How I and My Sister Configure and Dive Our O2ptima's for Sport Diving.

1) I dive with a standard O2ptima, using either LP27s or more recently mostly HP13's. My sister uses a custom O2ptima that was cut down in size for her (what was to become a protogenitor for the FX model), and uses AL13's or rarely AL6's. We both normally use Normoxic Trimix 21/35 as our Dil. However, I have been experimenting with super rich (>70%) helium trimixes.

2) The standard over the shoulder compact SPG's have been removed. In their place are the small mini-spg's that screw directly into to HP port on the first stages.

3) The upstream oxygen injection tube that runs from the solenoid through the cartidge has been removed. This means that the cartridge must now be installed with it's center plug remaining in place.

4) The head has been drilled and VR3 cable has been installed to independently monitor a fourth oxygen sensor. The VR3 cable runs down the right arm and terminates in the wrist mounted VR3. The VR3 is 'inverted' with the buttons at the top and the VR3 configuration option to rotate the display 180 degrees has been enabled. (The reason for the right arm mounting is only because both my sister and I have monocular corrected vision, and our right eye is better for reading the display, otherwise we would have it on our left arm.)

5) Both handsets have had the wrist straps and bolt snaps removed, they are stowed in the special purpose Dive Rite waistbelt handset pockets. The secondary pocket is pushed as far back as possible on the divers right side. The position of the primary pocket differs between our rebreathers. On mine, the pocket is again pushed as far back as possible on the divers left side. On my sister, because she is very petite and the sidemount bailout obscures her access to the handset, she prefers the pocket is pushed forward to the front and just to her left of the buckle.

6) The HUD's are configured in PPO2 mode, where the actual PPO2 reading for each of three sensors is displayed in the HUD. The VR3's display the 4th sensor readings and also have xDec calcuations using VPM enabled.

7) I use standard counterlungs, my sister uses a customized set of counterlungs that have been cutdown in size. My sister threads her counterlungs on the harness and uses the supplied V strap. My counterlungs are not threaded and 'float free' secured only by the top and bottom clips. I have replaced the V strap with two separate clips that use custom adjustable straps and bungie loops mounted on belt slides.

8) We both dive with TransPacs. I use a Venture wing, my sister uses a customized Travel wing. The wings have a BC integrated Rite Source supplied by the diluent cylinder. The assembly screws have been reversed and placed very tightly into the frame, causing them to protrude in a manner similar to doubles bolts. We assemble with wingnuts using TransPac doubles mounting plates that have been partially flattened.

9) The TransPac waist belts on both our harnesses carry a Dive Rite clipper Pocket and pair of trama shears. The clipper pocket normally contains a slate and may contain other items such as a table or in the case of my sister - shells. We carry a lift bag in a sleeve attached to the base of the Transpac, and a reel clipped on the right side. Sometimes we have an extra lift bag tucked on to the bailout cylinder. My sister almost always enters the water with one or more cameras clipped to her harness.

10) We both sidemount our bailouts. I use the standard Dive Rite solution. My sister, because of her size, uses a custom made side mount solution. In less than 75 fsw max depth dives, with 27's or 13's we bailout to dil, and may or may not take an outboard bailout.. I usually do, she usually doesn't. Deeper, but within sport depths, she uses an AL13 and I use an AL19 as bailout. We have done very extensive bailout trials and are comfortable with these procedures and volumes as being adequate (note, we both have exceptionally low RMV's).

11) For assembly and disassembly, post assembly checks, pre-dive checks and pre-breathe we use detailed checklists developed by me with input and review from several sources.

12) We both dive our units by manually adding O2 and keeping ahead of any automatic addition by the electronics. My sister usually sets 0.4 prior to entry on her primary and just leaves it there for the entire dive, manually maintaining a PO2 of 1.2 or perhaps 1.0 for long shallow dives. I usually set 0.7 prior to entry and change to 1.0 or 1.2 on the bottom, then manually keep ahead of the electronics. Thus she never touches or looks at either handset in the water, and I only touch the primary once. My sister tends to prefer the HUD for monitoring her PO2, I tend to prefer the VR3, but we do crosscheck one against the other occassionally. On ascent we both usually try to maintain 1.4 or higher.

Comments, observations and suggestions are welcome...

Also, some of my sister's videos contain some 'incidental' shots of me swimming in my configuration... see the wreck videos in particular at "http://www.fillexpress.com/video/"

RAL · 13th February 2007, 17:49

Quote: (Originally Posted by n2diving)

How I and My Sister Configure and Dive Our O2ptima's for Sport Diving.

10) We both sidemount our bailouts. I use the standard Dive Rite solution. My sister, because of her size, uses a custom made side mount solution. In less than 75 fsw max depth dives, with 27's or 13's we bailout to dil, and may or may not take an outboard bailout.. I usually do, she usually doesn't. Deeper, but within sport depths, she uses an AL13 and I use an AL19 as bailout. We have done very extensive bailout trials and are comfortable with these procedures and volumes as being adequate (note, we both have exceptionally low RMV's).

"

You may find that your RMV under calm conditions is a bit less than when things have gone south fast & hard. IMHO those small bottles may not be good for much more than a couple deep breaths and a long scream.

RAL

n2diving · 13th February 2007, 19:40

Quote: (Originally Posted by RAL)

You may find that your RMV under calm conditions is a bit less than when things have gone south fast & hard. IMHO those small bottles may not be good for much more than a couple deep breaths and a long scream.

RAL

As you point out, in stressful situations RMV can and does increase, and increase dramatically when the diver has not been trained to control their RMV. I'm familiar with our RMV's values under a range of conditions, including some exceptionally unfavorable conditions.

We have done the work and can state that the bailouts we carry are a great deal more than a 'couple of deep breaths'. This is not based on assumptions or conjecture.

We have each done literally dozens of test bailouts, including some hard swimming bailouts, plus one genuine emergency bailout and have confidence that the configurations we have chosen are adequate for the dives we are doing. Both of us also practice bailouts regularly. Obviously, more bailout is always better, but we do adjust our configurations based on our dive and the conditions. We have carefully documented the volumes required and they are adequate. Keep in mind that this is for our recreational sport diving under a set of very specific conditions. We are not recommending them for others, and I am certain our bailout configurations would be found inadequate for (and by) many other divers.

zmcave · 14th February 2007, 00:36

thanks for sharing. some questions:

how do you feel the super rich helium content has helped with WOB on sport dives?

why did you took out the premix rod? from what you wrote I understand that both of you fly the unit manually. Having the rod or not doesn't really change a lot in terms where the O2 is injected, usually manually on the exale CL.

Zé.

***ScubaDadMiami*** · 14th February 2007, 00:57

I am also curious about the premix rod removal. Would you explain more about why you did this, and what the results of doing so are?

Also, what have you found that was better, different by replacing the v-strap for the counterlungs, instead attaching via the clips to the waist?

sensor330 · 14th February 2007, 02:02

[quote=n2diving;96125]

12) Thus she never touches or looks at either handset in the water, and I only touch the primary once. [quote]

IMO I think she is playing with fire if she doesnt look at either handset during the dive. Maybe a little bit of a grey area but to me cross checking both handsets and the HUD go hand in hand with "Always know your PO2".

I had my primary handset pack it in. It was not reading the same as the secondary and I'm not talking about being out by .1 it was a considerable amount more.

Scott

Jordan · 14th February 2007, 03:13

[quote=sensor330;96233][quote=n2diving;96125]

12) Thus she never touches or looks at either handset in the water, and I only touch the primary once.

Quote:

IMO I think she is playing with fire if she doesnt look at either handset during the dive. Maybe a little bit of a grey area but to me cross checking both handsets and the HUD go hand in hand with "Always know your PO2".

I had my primary handset pack it in. It was not reading the same as the secondary and I'm not talking about being out by .1 it was a considerable amount more.

Scott

That caught my eye strange initially, as well. Then I thought a bit and I guess their rational would be that they are still checking 2 independant PO2 displays....they trust their HUD to be working as the first, and monitor the computer att'd to the 4th cell, in this case VR3's (that should be changing soon to a new toy, however!) as their other.

***ScubaDadMiami*** · 14th February 2007, 13:04

Quote: (Originally Posted by Jordan)

VR3's (that should be changing soon to a new toy, however!) . . . .

Toy? What new toy?

n2diving · 14th February 2007, 14:12

Premix Rod: As pointed out, the premix rod provides very little benefit in our situation because we inject the O2 in the exhalation CL. Thus for us it adds complexitity with little or no perceived benefit. Since increased complexity incurs increased risk, I elected to remove it because its absence makes cartridge loading easier. I'm not recommending it's removal, and I don't know Dive Rite's official position on removal (or even if they have a position). I do know we are not the only ones to have done so.

Primary Monitoring: It's unclear to me how not monitoring the primary handset in our configuration could lead to a situation where we did not know our PO2. The typical configuration does require the diver to compare the primary display to the secondary HUD. However, we are monitoring PO2's via four sensors, three via the HUD of the secondary and one completely independent sensor via the VR3, none of which are dependent on operation of the primary. I suppose the primary could fail in two ways: one such that it fires the solenoid and causes a high PO2 or the other such that it does not fire the solenoid and causes a low PO2. In our case, failure of the primary such that a low PO2 is caused is unlikely since we don't rely upon the primary to maintain PO2 and such a failure would go unnoticed. A high PO2 would be noticed by our monitoring the four sensors from two other independent sources as well as the sound of the solenoid firing, which would be abnormal.

The risk would seem to be an unnoticed failure of the 'backup' function of the primary. We do check the operation of the primary correctly maintaining setpoint prior to entry. To me, it seems we have adequate redundancy without incurring additional burden of monitoring the two handset displays directly during the dive. However, I welcome further evaluation of the risks.

Helium Rich Mixtures: The WOB in the O2ptima is already so good that I have seen only minor improvements for super rich mixtures vs 21/35 in recreational depths. The primary reason for the experimentation was examine how much the flying after diving time could be shortened by replacing nitrogen with helium.

Crazyduck · 14th February 2007, 14:41

Couple of questions if I could.

1. So you have no bailout tank- I understand this.
Do you have a second stage attached to the Diluent tank?
Or do you consider the adv suitable for bailout?

2. Are you going to just use the plastic plug for the scrubber or do you plan to eventually make a delrin insert?

3. Have you considered diving without a full cover?
Mount both tanks to a backplate and using the top two loops off the backplate (were you attach the shoulder harnesses) for attachment points for the scrubber.
Just curious.

There seems to be a lot going on with the electronics.
You have two handsets, a VR3 and you are flying the unit manually above setpoint. While I understand you are using the electronics as a parachute.

4. What is the decay rate for the between the injection at recreational depth?

5. Would it be easier to add a hose with (Kiss style gas addition) with a laser cut orifice and a ball valve? That way you have a constant gas addition and you maintain the factory oxygen addition system separate. This has been done with other units.

Thanks for your time.
Regards, Andrew

13th February 2007, 17:15	#1 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 271	My O2ptima Configuration How I and My Sister Configure and Dive Our O2ptima's for Sport Diving. 1) I dive with a standard O2ptima, using either LP27s or more recently mostly HP13's. My sister uses a custom O2ptima that was cut down in size for her (what was to become a protogenitor for the FX model), and uses AL13's or rarely AL6's. We both normally use Normoxic Trimix 21/35 as our Dil. However, I have been experimenting with super rich (>70%) helium trimixes. 2) The standard over the shoulder compact SPG's have been removed. In their place are the small mini-spg's that screw directly into to HP port on the first stages. 3) The upstream oxygen injection tube that runs from the solenoid through the cartidge has been removed. This means that the cartridge must now be installed with it's center plug remaining in place. 4) The head has been drilled and VR3 cable has been installed to independently monitor a fourth oxygen sensor. The VR3 cable runs down the right arm and terminates in the wrist mounted VR3. The VR3 is 'inverted' with the buttons at the top and the VR3 configuration option to rotate the display 180 degrees has been enabled. (The reason for the right arm mounting is only because both my sister and I have monocular corrected vision, and our right eye is better for reading the display, otherwise we would have it on our left arm.) 5) Both handsets have had the wrist straps and bolt snaps removed, they are stowed in the special purpose Dive Rite waistbelt handset pockets. The secondary pocket is pushed as far back as possible on the divers right side. The position of the primary pocket differs between our rebreathers. On mine, the pocket is again pushed as far back as possible on the divers left side. On my sister, because she is very petite and the sidemount bailout obscures her access to the handset, she prefers the pocket is pushed forward to the front and just to her left of the buckle. 6) The HUD's are configured in PPO2 mode, where the actual PPO2 reading for each of three sensors is displayed in the HUD. The VR3's display the 4th sensor readings and also have xDec calcuations using VPM enabled. 7) I use standard counterlungs, my sister uses a customized set of counterlungs that have been cutdown in size. My sister threads her counterlungs on the harness and uses the supplied V strap. My counterlungs are not threaded and 'float free' secured only by the top and bottom clips. I have replaced the V strap with two separate clips that use custom adjustable straps and bungie loops mounted on belt slides. 8) We both dive with TransPacs. I use a Venture wing, my sister uses a customized Travel wing. The wings have a BC integrated Rite Source supplied by the diluent cylinder. The assembly screws have been reversed and placed very tightly into the frame, causing them to protrude in a manner similar to doubles bolts. We assemble with wingnuts using TransPac doubles mounting plates that have been partially flattened. 9) The TransPac waist belts on both our harnesses carry a Dive Rite clipper Pocket and pair of trama shears. The clipper pocket normally contains a slate and may contain other items such as a table or in the case of my sister - shells. We carry a lift bag in a sleeve attached to the base of the Transpac, and a reel clipped on the right side. Sometimes we have an extra lift bag tucked on to the bailout cylinder. My sister almost always enters the water with one or more cameras clipped to her harness. 10) We both sidemount our bailouts. I use the standard Dive Rite solution. My sister, because of her size, uses a custom made side mount solution. In less than 75 fsw max depth dives, with 27's or 13's we bailout to dil, and may or may not take an outboard bailout.. I usually do, she usually doesn't. Deeper, but within sport depths, she uses an AL13 and I use an AL19 as bailout. We have done very extensive bailout trials and are comfortable with these procedures and volumes as being adequate (note, we both have exceptionally low RMV's). 11) For assembly and disassembly, post assembly checks, pre-dive checks and pre-breathe we use detailed checklists developed by me with input and review from several sources. 12) We both dive our units by manually adding O2 and keeping ahead of any automatic addition by the electronics. My sister usually sets 0.4 prior to entry on her primary and just leaves it there for the entire dive, manually maintaining a PO2 of 1.2 or perhaps 1.0 for long shallow dives. I usually set 0.7 prior to entry and change to 1.0 or 1.2 on the bottom, then manually keep ahead of the electronics. Thus she never touches or looks at either handset in the water, and I only touch the primary once. My sister tends to prefer the HUD for monitoring her PO2, I tend to prefer the VR3, but we do crosscheck one against the other occassionally. On ascent we both usually try to maintain 1.4 or higher. Comments, observations and suggestions are welcome... Also, some of my sister's videos contain some 'incidental' shots of me swimming in my configuration... see the wreck videos in particular at "http://www.fillexpress.com/video/" Last edited by n2diving : 13th February 2007 at 17:30.
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13th February 2007, 17:49	#2 (permalink)
RAL Longbottom Time Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jan 2006 Location: North Florida Posts: 389	Re: My O2ptima Configuration Quote: (Originally Posted by n2diving) How I and My Sister Configure and Dive Our O2ptima's for Sport Diving. 10) We both sidemount our bailouts. I use the standard Dive Rite solution. My sister, because of her size, uses a custom made side mount solution. In less than 75 fsw max depth dives, with 27's or 13's we bailout to dil, and may or may not take an outboard bailout.. I usually do, she usually doesn't. Deeper, but within sport depths, she uses an AL13 and I use an AL19 as bailout. We have done very extensive bailout trials and are comfortable with these procedures and volumes as being adequate (note, we both have exceptionally low RMV's). " You may find that your RMV under calm conditions is a bit less than when things have gone south fast & hard. IMHO those small bottles may not be good for much more than a couple deep breaths and a long scream. RAL __________________ The sea does not care about you.
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13th February 2007, 19:40	#3 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 271	Re: My O2ptima Configuration Quote: (Originally Posted by RAL) You may find that your RMV under calm conditions is a bit less than when things have gone south fast & hard. IMHO those small bottles may not be good for much more than a couple deep breaths and a long scream. RAL As you point out, in stressful situations RMV can and does increase, and increase dramatically when the diver has not been trained to control their RMV. I'm familiar with our RMV's values under a range of conditions, including some exceptionally unfavorable conditions. We have done the work and can state that the bailouts we carry are a great deal more than a 'couple of deep breaths'. This is not based on assumptions or conjecture. We have each done literally dozens of test bailouts, including some hard swimming bailouts, plus one genuine emergency bailout and have confidence that the configurations we have chosen are adequate for the dives we are doing. Both of us also practice bailouts regularly. Obviously, more bailout is always better, but we do adjust our configurations based on our dive and the conditions. We have carefully documented the volumes required and they are adequate. Keep in mind that this is for our recreational sport diving under a set of very specific conditions. We are not recommending them for others, and I am certain our bailout configurations would be found inadequate for (and by) many other divers. Last edited by n2diving : 13th February 2007 at 21:34.
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14th February 2007, 00:36	#4 (permalink)
zmcave www.rebreather.com.br Current Rebreather/s: Optima Dolphin Other Rebreather/s: Optima Dolphin Join Date: Apr 2006 Location: Brazil Posts: 186	Re: My O2ptima Configuration thanks for sharing. some questions: how do you feel the super rich helium content has helped with WOB on sport dives? why did you took out the premix rod? from what you wrote I understand that both of you fly the unit manually. Having the rod or not doesn't really change a lot in terms where the O2 is injected, usually manually on the exale CL. Zé.
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14th February 2007, 00:57	#5 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,136	Re: My O2ptima Configuration I am also curious about the premix rod removal. Would you explain more about why you did this, and what the results of doing so are? Also, what have you found that was better, different by replacing the v-strap for the counterlungs, instead attaching via the clips to the waist? __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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14th February 2007, 02:02	#6 (permalink)
sensor330 Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Not Bought Yet Inspiration Classic Join Date: Feb 2005 Location: Victoria, British Columbia, Canada Posts: 581	Re: My O2ptima Configuration [quote=n2diving;96125] 12) Thus she never touches or looks at either handset in the water, and I only touch the primary once. [quote] IMO I think she is playing with fire if she doesnt look at either handset during the dive. Maybe a little bit of a grey area but to me cross checking both handsets and the HUD go hand in hand with "Always know your PO2". I had my primary handset pack it in. It was not reading the same as the secondary and I'm not talking about being out by .1 it was a considerable amount more. Scott
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14th February 2007, 03:13	#7 (permalink)
Jordan EBT called me stroppy! Current Rebreather/s: Optima Other Rebreather/s: Join Date: May 2005 Location: Garner, NC Posts: 226	Re: My O2ptima Configuration [quote=sensor330;96233][quote=n2diving;96125] 12) Thus she never touches or looks at either handset in the water, and I only touch the primary once. Quote: IMO I think she is playing with fire if she doesnt look at either handset during the dive. Maybe a little bit of a grey area but to me cross checking both handsets and the HUD go hand in hand with "Always know your PO2". I had my primary handset pack it in. It was not reading the same as the secondary and I'm not talking about being out by .1 it was a considerable amount more. Scott That caught my eye strange initially, as well. Then I thought a bit and I guess their rational would be that they are still checking 2 independant PO2 displays....they trust their HUD to be working as the first, and monitor the computer att'd to the 4th cell, in this case VR3's (that should be changing soon to a new toy, however!) as their other. __________________ Is it clear? No. Well, let's go anyways. "Those who would sacrifice a little freedom for a little order, will lose both, and deserve neither." Thomas Jefferson
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14th February 2007, 13:04	#8 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,136	Re: My O2ptima Configuration Quote: (Originally Posted by Jordan) VR3's (that should be changing soon to a new toy, however!) . . . . Toy? What new toy? __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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14th February 2007, 14:12	#9 (permalink)
n2diving Custom Title Allowed! Current Rebreather/s: Optima Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Feb 2005 Location: Florida, USA Posts: 271	Re: My O2ptima Configuration Premix Rod: As pointed out, the premix rod provides very little benefit in our situation because we inject the O2 in the exhalation CL. Thus for us it adds complexitity with little or no perceived benefit. Since increased complexity incurs increased risk, I elected to remove it because its absence makes cartridge loading easier. I'm not recommending it's removal, and I don't know Dive Rite's official position on removal (or even if they have a position). I do know we are not the only ones to have done so. Primary Monitoring: It's unclear to me how not monitoring the primary handset in our configuration could lead to a situation where we did not know our PO2. The typical configuration does require the diver to compare the primary display to the secondary HUD. However, we are monitoring PO2's via four sensors, three via the HUD of the secondary and one completely independent sensor via the VR3, none of which are dependent on operation of the primary. I suppose the primary could fail in two ways: one such that it fires the solenoid and causes a high PO2 or the other such that it does not fire the solenoid and causes a low PO2. In our case, failure of the primary such that a low PO2 is caused is unlikely since we don't rely upon the primary to maintain PO2 and such a failure would go unnoticed. A high PO2 would be noticed by our monitoring the four sensors from two other independent sources as well as the sound of the solenoid firing, which would be abnormal. The risk would seem to be an unnoticed failure of the 'backup' function of the primary. We do check the operation of the primary correctly maintaining setpoint prior to entry. To me, it seems we have adequate redundancy without incurring additional burden of monitoring the two handset displays directly during the dive. However, I welcome further evaluation of the risks. Helium Rich Mixtures: The WOB in the O2ptima is already so good that I have seen only minor improvements for super rich mixtures vs 21/35 in recreational depths. The primary reason for the experimentation was examine how much the flying after diving time could be shortened by replacing nitrogen with helium. Last edited by n2diving : 14th February 2007 at 14:48.
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14th February 2007, 14:41	#10 (permalink)
Crazyduck Underwater Mechanic Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Mar 2005 Location: TEXAS, Dallas/ Ft.Worth Posts: 712	Re: My O2ptima Configuration Couple of questions if I could. 1. So you have no bailout tank- I understand this. Do you have a second stage attached to the Diluent tank? Or do you consider the adv suitable for bailout? 2. Are you going to just use the plastic plug for the scrubber or do you plan to eventually make a delrin insert? 3. Have you considered diving without a full cover? Mount both tanks to a backplate and using the top two loops off the backplate (were you attach the shoulder harnesses) for attachment points for the scrubber. Just curious. There seems to be a lot going on with the electronics. You have two handsets, a VR3 and you are flying the unit manually above setpoint. While I understand you are using the electronics as a parachute. 4. What is the decay rate for the between the injection at recreational depth? 5. Would it be easier to add a hose with (Kiss style gas addition) with a laser cut orifice and a ball valve? That way you have a constant gas addition and you maintain the factory oxygen addition system separate. This has been done with other units. Thanks for your time. Regards, Andrew __________________ Howdy Senor- What’s Happening! Rob Davie April 2005- Presently in a state of transition from Open Circuit to Closed Circuit. "You will not be punished for your anger; you will be punished by it." - Buddha.
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