What setpoint for 100m+ diving do you use?

rogeringebo · 13th February 2008, 03:07

Hi Mike!
I know you have a lot of experience in deep CCR diving.
What have you learned over the years when it comes to planning the dive, working out bailout, safety factors, algorithms and so on?
Where do you put your po2 on the bottom phase on a dive like this?
It would be interesting to hear about your lessons learned if you would like to share them.

Roger

Drmike · 13th February 2008, 03:17

High inspired ppHe and high retained CO2 are contributors to O2 tox

On deep dives does running high ppo2s at depth offer any significant deco advantage? - increasingly (As you go deeper) no

on deep dives you are using high ppHe and likely enjoying higher retained CO2 (due to a) rapid descents, b) higher gas densities c) respiratory issues associated with high ambient pressures, wob ect) Do you really want to be breathing high PPO2s during times of high ppHE and higher CO2? especially when the higher ppo2 offers little to no deco advantage?

Getting down to depth is often a time of exertion. do you really want to be breathing high ppO2 at depth during times of high exertion??

How long does it take to reach depth? Not long if doing typical bounce dive

Fast descent speeds with high setpoint is recipe for ppop2 overshoot during descent (especially if using rich dil) as well as poor lung ventilation

What I do is split the dive into sections and determine empirically the optimum setopiont for each stage:

The 1st draft using v-planner is done by temp setting a deco baseline of setpoint 1.3 from start of bottom time up to 6m then O2. (ignoring for time being CNS)

Now I plug in different setpoints for descent and see how that affects deco time. 99% of the time (with anything but the very slowest descents, or if cave) the start and descent ppo2 has no effect on deco so Id start with a low one - say 1.0. This also prevents spiking of poo2 on descent and helps minimise O2 tix risk (see above)

Now (assuming descent setpoint of 1.0 1.3 for ascent and O2 at 6m) I look at the bottom setpoint. I plug in different bottom ppo2s to see effect on deco. Depending on depth and BT high ppo2s often add little to nothing to deco (I consider a 30min reduction in deco nothing when balanced against O2 risk)

Lets say bottom time is relatively short as we are deep increasingly hiher setpionts offer min to non deco advanteg so perhaps a setpoint of 1.1 is reasonable.

Now I look at ascent.

Usually what I do is split the ascent into sections and play around with increasing setpoint at various depths in stages to find optimum depth/setpoint increase. No point (for eg) running 1.3 from 100m upwards if I can get sane deco time running say 1.1 up to 60m, 1.2 to 30m and 1.3 from 20m - as way of example)

By way of quick example:

same dive but one with optimized setpoint switching:-

Dec to 110m (5:30) Diluents 7/70 1.30 SetPoint, 20m/min descent.
Dec to 125m (6:15) Diluent 7/70 1.30 SetPoint, 20m/min descent.
Dec to 150m (7:55) Diluent 7/70 1.30 SetPoint, 15m/min descent.
Level 150m 12:05 (20:00) Diluent 7/70 1.30 SetPoint, 36m ead, 39m end
Asc to 126m (22:24) Diluent 7/70 1.30 SetPoint, -10m/min ascent.
Stop at 120m 1:06 (23:30) Diluent 7/70 1.30 SetPoint, 26m ead, 32m end
Stop at 114m 1:00 (24:30) Diluent 7/70 1.30 SetPoint, 24m ead, 30m end
Stop at 108m 1:30 (26:00) Diluent 7/70 1.30 SetPoint, 23m ead, 29m end
Stop at 102m 1:30 (27:30) Diluent 7/70 1.30 SetPoint, 21m ead, 27m end
Stop at 96m 1:30 (29:00) Diluent 7/70 1.30 SetPoint, 19m ead, 26m end
Stop at 90m 2:00 (31:00) Diluent 7/70 1.30 SetPoint, 17m ead, 24m end
Stop at 84m 2:30 (33:30) Diluent 7/70 1.30 SetPoint, 15m ead, 23m end
Stop at 78m 2:30 (36:00) Diluent 7/70 1.30 SetPoint, 13m ead, 21m end
Stop at 72m 3:30 (39:30) Diluent 7/70 1.30 SetPoint, 11m ead, 20m end
Stop at 66m 3:30 (43:00) Diluent 7/70 1.30 SetPoint, 9m ead, 19m end
Stop at 60m 5:30 (48:30) Diluent 7/70 1.30 SetPoint, 8m ead, 17m end
Stop at 54m 5:00 (53:30) Diluent 7/70 1.30 SetPoint, 6m ead, 16m end
Stop at 48m 7:30 (61:00) Diluent 7/70 1.30 SetPoint, 4m ead, 14m end
Stop at 42m 9:00 (70:00) Diluent 7/70 1.30 SetPoint, 2m ead, 13m end
Stop at 36m 11:00 (81:00) Diluent 7/70 1.30 SetPoint, 0m ead, 11m end
Stop at 30m 15:30 (96:30) Diluent 7/70 1.30 SetPoint, 0m ead, 10m end
Stop at 24m 22:30 (119:00) Diluent 7/70 1.30 SetPoint, 0m ead, 8m end
Stop at 18m 35:30 (154:30) Diluent 7/70 1.30 SetPoint, 0m ead, 7m end
Stop at 12m 61:30 (216:00) Diluent 7/70 1.30 SetPoint, 0m ead, 5m end
Stop at 6m 110:30 (326:30) Oxygen 1.58 ppO2, 0m ead
Surface (327:06) Oxygen -10m/min ascent.
Off gassing starts at 129.5m
OTU's this dive: 530
CNS Total: 283.2%
2617.0 ltr Oxygen
2617 ltr OC TOTAL

Dec to 110m (5:30) Diluent 7/70 1.00 SetPoint, 20m/min descent.
Dec to 125m (6:15) Diluent 7/70 1.00 SetPoint, 20m/min descent.
Dec to 150m (7:55) Diluent 7/70 1.00 SetPoint, 15m/min descent.
Level 150m 12:05 (20:00) Diluent 7/70 1.10 SetPoint, 36m ead, 38m end
Asc to 126m (22:24) Diluent 7/70 1.20 SetPoint, -10m/min ascent.
Stop at 120m 1:06 (23:30) Diluent 7/70 1.20 SetPoint, 27m ead, 31m end
Stop at 114m 1:00 (24:30) Diluent 7/70 1.20 SetPoint, 25m ead, 30m end
Stop at 108m 1:30 (26:00) Diluent 7/70 1.20 SetPoint, 23m ead, 28m end
Stop at 102m 2:00 (28:00) Diluent 7/70 1.20 SetPoint, 21m ead, 27m end
Stop at 96m 1:30 (29:30) Diluent 7/70 1.20 SetPoint, 19m ead, 25m end
Stop at 90m 2:30 (32:00) Diluent 7/70 1.20 SetPoint, 17m ead, 24m end
Stop at 84m 2:30 (34:30) Diluent 7/70 1.20 SetPoint, 15m ead, 22m end
Stop at 78m 3:00 (37:30) Diluent 7/70 1.20 SetPoint, 13m ead, 21m end
Stop at 72m 3:30 (41:00) Diluent 7/70 1.20 SetPoint, 12m ead, 19m end
Stop at 66m 4:30 (45:30) Diluent 7/70 1.20 SetPoint, 10m ead, 18m end
Stop at 60m 5:00 (50:30) Diluent 7/70 1.30 SetPoint, 8m ead, 17m end
Stop at 54m 6:00 (56:30) Diluent 7/70 1.30 SetPoint, 6m ead, 16m end
Stop at 48m 7:30 (64:00) Diluent 7/70 1.30 SetPoint, 4m ead, 14m end
Stop at 42m 9:30 (73:30) Diluent 7/70 1.30 SetPoint, 2m ead, 13m end
Stop at 36m 11:30 (85:00) Diluent 7/70 1.30 SetPoint, 0m ead, 11m end
Stop at 30m 16:30 (101:30) Diluent 7/70 1.30 SetPoint, 0m ead, 10m end
Stop at 24m 23:30 (125:00) Diluent 7/70 1.30 SetPoint, 0m ead, 8m end
Stop at 18m 37:00 (162:00) Diluent 7/70 1.30 SetPoint, 0m ead, 7m end
Stop at 12m 65:30 (227:30) Diluent 7/70 1.30 SetPoint, 0m ead, 5m end
Stop at 6m 125:30 (353:00) Diluent 7/70 1.45 SetPoint, 0m ead, 5m end
Surface (353:36) Diluent 7/70 -10m/min ascent.
Off gassing starts at 132.1m
OTU's this dive: 540
CNS Total: 212.1%

Optimised setpoint switching gives me similar run times but with setpoint switching I am on much lower (safer) ppo2 at depth I dont fry my lungs on 1.6 during deco thety remain efficenr for offgassing and overall reduction in CNS (if you think that means anything)

Id rather have 30m longer deco for a drop in setpoint of just 0.1 at the bottom than not.

Drmike · 13th February 2008, 03:32

Quote: (Originally Posted by rogeringebo)

Hi Mike!
I know you have a lot of experience in deep CCR diving.
What have you learned over the years when it comes to planning the dive, working out bailout, safety factors, algorithms and so on?
Where do you put your po2 on the bottom phase on a dive like this?
It would be interesting to hear about your lessons learned if you would like to share them.

Roger

Hi Roger,

I am conservative.

My approach is 'anything that is unknown is great risk' 'long deco is not a risk'

I can 'manage' deco to make it safe (enough gas, hydrated, habitat etc) but you cant 'manage' the unknowns - so to me they are a greater risk and need to be illiminated or I have to be very conservative with them.

To me O2 tox and CO2 are biggest unknowns and risks

CO2 I manage by diving a unit with great wob, use of scooter and knowing my limits

O2 tox (and efficent lung off gassing) I manage by being very conservative with ppo2s and considering what Im doing when im breathing them (high ppo2 during resting deco is infinitely safer than medium high poo2 during working part of dive)

I dont run unecessary high PPO2s. I take the time to determine if the benefit (slightly shorter run times) outweigh the unknown risk (possible death)

Often theres no advantage to running high ppo2s at depth. Where we need increasingly high ppo2s is during ascent but there is a possible disadvantage as we are on high He mixes and exerting at depth - both contributors to toxing.

Theres still so much we dont know for sure about this stuff. I stay on the loop when possible and dont do air breaks even on 8+hr long dives because I dont take high ppo2s. YMMV

For deco I blindly follow VPM VR3 for all dives regardless of depth and duration (2 VR3 and tables as back up) What works-works

For bailout, you dont have enough. thats what Ive learnt

Best method is to carefully calculate exactly how much bail gas you need then double it - you may then be close . people planning RMV <30 at bottom are deluding the sh1t out of themselves

Big dives im using bail gas and bail Rebreather for added safety and because if you use a realistic bottom RMV its a silly number of stage tanks

For planning; i plan the dive using v-planner, I execute it using VPM VR3. If I bail I bail following Vr3 and likely blow some of the deep stops

Gilles · 13th February 2008, 03:55

Quote: (Originally Posted by Drmike)

if you dont know what your talking about - why talk?

So I can get auto email replies to my PDA. Is that such a bother for you?

mattmexico · 13th February 2008, 03:56

yo

On the described 120 meter - 400 foot dive I did not do air breaks but have done so before and after. Feeling is you can do very high CNS exposure well over 100 % and be safe if you do air - low po2 breaks.

Matt

rogeringebo · 13th February 2008, 04:15

[quote=Drmike;168492]Hi Roger,

I am conservative.

My approach is 'anything that is unknown is great risk' 'long deco is not a risk'

I can 'manage' deco to make it safe (enough gas, hydrated, habitat etc) but you cant 'manage' the unknowns - so to me they are a greater risk and need to be illiminated or I have to be very conservative with them.

To me O2 tox and CO2 are biggest unknowns and risks

CO2 I manage by diving a unit with great wob, use of scooter and knowing my limits

Hi Mike!
Well said!
Manage what can be managed and avoid even getting close to what is harder to predict.
My buddy toxed and woke up on the boat in his underwear.
Luckily his buddy saved the day and now enjoy a lifetime of free Helium I would guess

Thank you for taking time to explain you thoughts!
Real life experience is invaluable.

Cheers
Rodge

Drmike · 13th February 2008, 04:19

Quote: (Originally Posted by rogeringebo)

My buddy toxed and woke up on the boat in his underwear.

Ive taken toxic substances and woken up on a boat without my underwear

does that count?

Drmike · 13th February 2008, 04:25

Quote: (Originally Posted by Gilles)

So I can get auto email replies to my PDA. Is that such a bother for you?

no bother for me - I feel just as loved and wanted without recieving emails from strangers to my PDA and I try not to offer advice on subjects I have no knowledge on - but thats just me

Drmike · 13th February 2008, 04:40

Quote: (Originally Posted by mattmexico)

yo

On the described 120 meter - 400 foot dive I did not do air breaks but have done so before and after. Feeling is you can do very high CNS exposure well over 100 % and be safe if you do air - low po2 breaks.

Matt

Hey Matt,

Yes air breaks lower risk of toxing and help maintain lung off gassing ability.

Personally I suspect the way we look at CNS is wrong. I wonder if it is really as cumulative as its presented.

I believe its the instantaneous ppo2 and the situation at that time that is far more critical. I can imagine a circumstance where someone with a CNS of 50% toxes because they are swimming hard with high ppHe and high setpoint, where as someone with a CNS of 200% sat on deco doing nothing with same setpoint is safer.

My point is I don't really worry about the CNS (as its traditionally measured) I concern myself with what my ppo2 is at a given time and given circumstance. There may well be a cumulative effect - but I suspect this is masked by the fact we are usually well into restful deco by the time the CNS creeps that high.

I don't like doing final stop on 1.6 as I find I feel like I'm suffocating after a while - air breaks temp relieve this feeling for me. But if i deco out on 1.4+ I feel no sense of choking up and as Im on on a lower setpoint I suspect the lungs are less effected, risk of toxing is reduced (exponentially for small changes in ppoo2)

for the deep dives im doing, often the advantage of decoing out on 1.6 over 1.45 is negliable to non existant

(Personally on a big dive Id rather to an extra 45mins of deco with setpoint 1.45 than deco out on 1.6 faster)

Gilles · 13th February 2008, 04:40

My sincere apologies to those who feel I polluted this thread!

13th February 2008, 03:07	#21 (permalink)
rogeringebo Done with bubbles Current Rebreather/s: Pelagian Other Rebreather/s: Megalodon Classic Kiss Pelagian Join Date: Sep 2005 Location: Stockholm Sweden Posts: 672	Re: What setpoint for 100m+ diving do you use? Hi Mike! I know you have a lot of experience in deep CCR diving. What have you learned over the years when it comes to planning the dive, working out bailout, safety factors, algorithms and so on? Where do you put your po2 on the bottom phase on a dive like this? It would be interesting to hear about your lessons learned if you would like to share them. Roger
(Offline)

13th February 2008, 03:17	#22 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: What setpoint for 100m+ diving do you use? High inspired ppHe and high retained CO2 are contributors to O2 tox On deep dives does running high ppo2s at depth offer any significant deco advantage? - increasingly (As you go deeper) no on deep dives you are using high ppHe and likely enjoying higher retained CO2 (due to a) rapid descents, b) higher gas densities c) respiratory issues associated with high ambient pressures, wob ect) Do you really want to be breathing high PPO2s during times of high ppHE and higher CO2? especially when the higher ppo2 offers little to no deco advantage? Getting down to depth is often a time of exertion. do you really want to be breathing high ppO2 at depth during times of high exertion?? How long does it take to reach depth? Not long if doing typical bounce dive Fast descent speeds with high setpoint is recipe for ppop2 overshoot during descent (especially if using rich dil) as well as poor lung ventilation What I do is split the dive into sections and determine empirically the optimum setopiont for each stage: The 1st draft using v-planner is done by temp setting a deco baseline of setpoint 1.3 from start of bottom time up to 6m then O2. (ignoring for time being CNS) Now I plug in different setpoints for descent and see how that affects deco time. 99% of the time (with anything but the very slowest descents, or if cave) the start and descent ppo2 has no effect on deco so Id start with a low one - say 1.0. This also prevents spiking of poo2 on descent and helps minimise O2 tix risk (see above) Now (assuming descent setpoint of 1.0 1.3 for ascent and O2 at 6m) I look at the bottom setpoint. I plug in different bottom ppo2s to see effect on deco. Depending on depth and BT high ppo2s often add little to nothing to deco (I consider a 30min reduction in deco nothing when balanced against O2 risk) Lets say bottom time is relatively short as we are deep increasingly hiher setpionts offer min to non deco advanteg so perhaps a setpoint of 1.1 is reasonable. Now I look at ascent. Usually what I do is split the ascent into sections and play around with increasing setpoint at various depths in stages to find optimum depth/setpoint increase. No point (for eg) running 1.3 from 100m upwards if I can get sane deco time running say 1.1 up to 60m, 1.2 to 30m and 1.3 from 20m - as way of example) By way of quick example: same dive but one with optimized setpoint switching:- Dec to 110m (5:30) Diluents 7/70 1.30 SetPoint, 20m/min descent. Dec to 125m (6:15) Diluent 7/70 1.30 SetPoint, 20m/min descent. Dec to 150m (7:55) Diluent 7/70 1.30 SetPoint, 15m/min descent. Level 150m 12:05 (20:00) Diluent 7/70 1.30 SetPoint, 36m ead, 39m end Asc to 126m (22:24) Diluent 7/70 1.30 SetPoint, -10m/min ascent. Stop at 120m 1:06 (23:30) Diluent 7/70 1.30 SetPoint, 26m ead, 32m end Stop at 114m 1:00 (24:30) Diluent 7/70 1.30 SetPoint, 24m ead, 30m end Stop at 108m 1:30 (26:00) Diluent 7/70 1.30 SetPoint, 23m ead, 29m end Stop at 102m 1:30 (27:30) Diluent 7/70 1.30 SetPoint, 21m ead, 27m end Stop at 96m 1:30 (29:00) Diluent 7/70 1.30 SetPoint, 19m ead, 26m end Stop at 90m 2:00 (31:00) Diluent 7/70 1.30 SetPoint, 17m ead, 24m end Stop at 84m 2:30 (33:30) Diluent 7/70 1.30 SetPoint, 15m ead, 23m end Stop at 78m 2:30 (36:00) Diluent 7/70 1.30 SetPoint, 13m ead, 21m end Stop at 72m 3:30 (39:30) Diluent 7/70 1.30 SetPoint, 11m ead, 20m end Stop at 66m 3:30 (43:00) Diluent 7/70 1.30 SetPoint, 9m ead, 19m end Stop at 60m 5:30 (48:30) Diluent 7/70 1.30 SetPoint, 8m ead, 17m end Stop at 54m 5:00 (53:30) Diluent 7/70 1.30 SetPoint, 6m ead, 16m end Stop at 48m 7:30 (61:00) Diluent 7/70 1.30 SetPoint, 4m ead, 14m end Stop at 42m 9:00 (70:00) Diluent 7/70 1.30 SetPoint, 2m ead, 13m end Stop at 36m 11:00 (81:00) Diluent 7/70 1.30 SetPoint, 0m ead, 11m end Stop at 30m 15:30 (96:30) Diluent 7/70 1.30 SetPoint, 0m ead, 10m end Stop at 24m 22:30 (119:00) Diluent 7/70 1.30 SetPoint, 0m ead, 8m end Stop at 18m 35:30 (154:30) Diluent 7/70 1.30 SetPoint, 0m ead, 7m end Stop at 12m 61:30 (216:00) Diluent 7/70 1.30 SetPoint, 0m ead, 5m end Stop at 6m 110:30 (326:30) Oxygen 1.58 ppO2, 0m ead Surface (327:06) Oxygen -10m/min ascent. Off gassing starts at 129.5m OTU's this dive: 530 CNS Total: 283.2% 2617.0 ltr Oxygen 2617 ltr OC TOTAL Dec to 110m (5:30) Diluent 7/70 1.00 SetPoint, 20m/min descent. Dec to 125m (6:15) Diluent 7/70 1.00 SetPoint, 20m/min descent. Dec to 150m (7:55) Diluent 7/70 1.00 SetPoint, 15m/min descent. Level 150m 12:05 (20:00) Diluent 7/70 1.10 SetPoint, 36m ead, 38m end Asc to 126m (22:24) Diluent 7/70 1.20 SetPoint, -10m/min ascent. Stop at 120m 1:06 (23:30) Diluent 7/70 1.20 SetPoint, 27m ead, 31m end Stop at 114m 1:00 (24:30) Diluent 7/70 1.20 SetPoint, 25m ead, 30m end Stop at 108m 1:30 (26:00) Diluent 7/70 1.20 SetPoint, 23m ead, 28m end Stop at 102m 2:00 (28:00) Diluent 7/70 1.20 SetPoint, 21m ead, 27m end Stop at 96m 1:30 (29:30) Diluent 7/70 1.20 SetPoint, 19m ead, 25m end Stop at 90m 2:30 (32:00) Diluent 7/70 1.20 SetPoint, 17m ead, 24m end Stop at 84m 2:30 (34:30) Diluent 7/70 1.20 SetPoint, 15m ead, 22m end Stop at 78m 3:00 (37:30) Diluent 7/70 1.20 SetPoint, 13m ead, 21m end Stop at 72m 3:30 (41:00) Diluent 7/70 1.20 SetPoint, 12m ead, 19m end Stop at 66m 4:30 (45:30) Diluent 7/70 1.20 SetPoint, 10m ead, 18m end Stop at 60m 5:00 (50:30) Diluent 7/70 1.30 SetPoint, 8m ead, 17m end Stop at 54m 6:00 (56:30) Diluent 7/70 1.30 SetPoint, 6m ead, 16m end Stop at 48m 7:30 (64:00) Diluent 7/70 1.30 SetPoint, 4m ead, 14m end Stop at 42m 9:30 (73:30) Diluent 7/70 1.30 SetPoint, 2m ead, 13m end Stop at 36m 11:30 (85:00) Diluent 7/70 1.30 SetPoint, 0m ead, 11m end Stop at 30m 16:30 (101:30) Diluent 7/70 1.30 SetPoint, 0m ead, 10m end Stop at 24m 23:30 (125:00) Diluent 7/70 1.30 SetPoint, 0m ead, 8m end Stop at 18m 37:00 (162:00) Diluent 7/70 1.30 SetPoint, 0m ead, 7m end Stop at 12m 65:30 (227:30) Diluent 7/70 1.30 SetPoint, 0m ead, 5m end Stop at 6m 125:30 (353:00) Diluent 7/70 1.45 SetPoint, 0m ead, 5m end Surface (353:36) Diluent 7/70 -10m/min ascent. Off gassing starts at 132.1m OTU's this dive: 540 CNS Total: 212.1% Optimised setpoint switching gives me similar run times but with setpoint switching I am on much lower (safer) ppo2 at depth I dont fry my lungs on 1.6 during deco thety remain efficenr for offgassing and overall reduction in CNS (if you think that means anything) Id rather have 30m longer deco for a drop in setpoint of just 0.1 at the bottom than not. __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 13th February 2008 at 03:48.
(Offline)

13th February 2008, 03:32	#23 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: What setpoint for 100m+ diving do you use? Quote: (Originally Posted by rogeringebo) Hi Mike! I know you have a lot of experience in deep CCR diving. What have you learned over the years when it comes to planning the dive, working out bailout, safety factors, algorithms and so on? Where do you put your po2 on the bottom phase on a dive like this? It would be interesting to hear about your lessons learned if you would like to share them. Roger Hi Roger, I am conservative. My approach is 'anything that is unknown is great risk' 'long deco is not a risk' I can 'manage' deco to make it safe (enough gas, hydrated, habitat etc) but you cant 'manage' the unknowns - so to me they are a greater risk and need to be illiminated or I have to be very conservative with them. To me O2 tox and CO2 are biggest unknowns and risks CO2 I manage by diving a unit with great wob, use of scooter and knowing my limits O2 tox (and efficent lung off gassing) I manage by being very conservative with ppo2s and considering what Im doing when im breathing them (high ppo2 during resting deco is infinitely safer than medium high poo2 during working part of dive) I dont run unecessary high PPO2s. I take the time to determine if the benefit (slightly shorter run times) outweigh the unknown risk (possible death) Often theres no advantage to running high ppo2s at depth. Where we need increasingly high ppo2s is during ascent but there is a possible disadvantage as we are on high He mixes and exerting at depth - both contributors to toxing. Theres still so much we dont know for sure about this stuff. I stay on the loop when possible and dont do air breaks even on 8+hr long dives because I dont take high ppo2s. YMMV For deco I blindly follow VPM VR3 for all dives regardless of depth and duration (2 VR3 and tables as back up) What works-works For bailout, you dont have enough. thats what Ive learnt Best method is to carefully calculate exactly how much bail gas you need then double it - you may then be close . people planning RMV <30 at bottom are deluding the sh1t out of themselves Big dives im using bail gas and bail Rebreather for added safety and because if you use a realistic bottom RMV its a silly number of stage tanks For planning; i plan the dive using v-planner, I execute it using VPM VR3. If I bail I bail following Vr3 and likely blow some of the deep stops __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 13th February 2008 at 03:42.
(Offline)

13th February 2008, 03:55	#24 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 761	Re: What setpoint for 100m+ diving do you use? Quote: (Originally Posted by Drmike) if you dont know what your talking about - why talk? So I can get auto email replies to my PDA. Is that such a bother for you? __________________ Gilles http://www.dirrebreather.com
(Offline)

13th February 2008, 03:56	#25 (permalink)
mattmexico Rebreather World Writer Current Rebreather/s: Megalodon Classic Kiss Optima RB80 / Clone Other Rebreather/s: Inspiration Classic Evolution Prism Topaz Sport Kiss RB80 / Clone Join Date: Aug 2005 Location: Mexico, Q.Roo, Playa del Carmen Posts: 736	Re: What setpoint for 100m+ diving do you use? yo On the described 120 meter - 400 foot dive I did not do air breaks but have done so before and after. Feeling is you can do very high CNS exposure well over 100 % and be safe if you do air - low po2 breaks. Matt __________________ N 20' 37.617' W 87' 04.693' www.andreaswmatthes.com
(Offline)

13th February 2008, 04:15	#26 (permalink)
rogeringebo Done with bubbles Current Rebreather/s: Pelagian Other Rebreather/s: Megalodon Classic Kiss Pelagian Join Date: Sep 2005 Location: Stockholm Sweden Posts: 672	Re: What setpoint for 100m+ diving do you use? [quote=Drmike;168492]Hi Roger, I am conservative. My approach is 'anything that is unknown is great risk' 'long deco is not a risk' I can 'manage' deco to make it safe (enough gas, hydrated, habitat etc) but you cant 'manage' the unknowns - so to me they are a greater risk and need to be illiminated or I have to be very conservative with them. To me O2 tox and CO2 are biggest unknowns and risks CO2 I manage by diving a unit with great wob, use of scooter and knowing my limits Hi Mike! Well said! Manage what can be managed and avoid even getting close to what is harder to predict. My buddy toxed and woke up on the boat in his underwear. Luckily his buddy saved the day and now enjoy a lifetime of free Helium I would guess Thank you for taking time to explain you thoughts! Real life experience is invaluable. Cheers Rodge
(Offline)

13th February 2008, 04:19	#27 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: What setpoint for 100m+ diving do you use? Quote: (Originally Posted by rogeringebo) My buddy toxed and woke up on the boat in his underwear. Ive taken toxic substances and woken up on a boat without my underwear does that count? __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
(Offline)

13th February 2008, 04:25	#28 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: What setpoint for 100m+ diving do you use? Quote: (Originally Posted by Gilles) So I can get auto email replies to my PDA. Is that such a bother for you? no bother for me - I feel just as loved and wanted without recieving emails from strangers to my PDA and I try not to offer advice on subjects I have no knowledge on - but thats just me __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
(Offline)

13th February 2008, 04:40	#29 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: What setpoint for 100m+ diving do you use? Quote: (Originally Posted by mattmexico) yo On the described 120 meter - 400 foot dive I did not do air breaks but have done so before and after. Feeling is you can do very high CNS exposure well over 100 % and be safe if you do air - low po2 breaks. Matt Hey Matt, Yes air breaks lower risk of toxing and help maintain lung off gassing ability. Personally I suspect the way we look at CNS is wrong. I wonder if it is really as cumulative as its presented. I believe its the instantaneous ppo2 and the situation at that time that is far more critical. I can imagine a circumstance where someone with a CNS of 50% toxes because they are swimming hard with high ppHe and high setpoint, where as someone with a CNS of 200% sat on deco doing nothing with same setpoint is safer. My point is I don't really worry about the CNS (as its traditionally measured) I concern myself with what my ppo2 is at a given time and given circumstance. There may well be a cumulative effect - but I suspect this is masked by the fact we are usually well into restful deco by the time the CNS creeps that high. I don't like doing final stop on 1.6 as I find I feel like I'm suffocating after a while - air breaks temp relieve this feeling for me. But if i deco out on 1.4+ I feel no sense of choking up and as Im on on a lower setpoint I suspect the lungs are less effected, risk of toxing is reduced (exponentially for small changes in ppoo2) for the deep dives im doing, often the advantage of decoing out on 1.6 over 1.45 is negliable to non existant (Personally on a big dive Id rather to an extra 45mins of deco with setpoint 1.45 than deco out on 1.6 faster) __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 13th February 2008 at 04:45.
(Offline)

13th February 2008, 04:40	#30 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 761	Re: What setpoint for 100m+ diving do you use? My sincere apologies to those who feel I polluted this thread! __________________ Gilles http://www.dirrebreather.com
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode