Poseidon MK6 CCR comes to St.Martin / St.Maarten

[teamoctopus]

Hi readers!

Octopus Diving Octopus Diving - Scuba Dive and Snorkel in Saint Martin / Sint Maarten in St. Martin / St. Maarten, Caribbean is pleased to anounce that we are the first rebreather friendly dive center on the Island.

We carry Sofnolime, 3 liter rental tanks (Dil and O2) and also have the ability to boost O2 to 3000psi / 200Bar.
Octopus Diving also carries 12 liter / 80 CU FT bail out / stages with Regs and 5 foot hoses for rental.

We offer rebreather trips and private charters for Rebreather divers with CCR courses coming up in the near future.

The Poseidon MK6 MOD 1 User and Instructor course starts in the last week of November 2010.
Please email for prices and more information to chris@octopusdiving.com
CCR course from Sally’s perspective | Octopus Diving | Scuba Diving & Snorkeling Saint Martin

Diving in St.Maarten is awesome, we have plenty of deep wrecks, reefs in fantastic condition and to see an abundance of marine life face to face with no bubbles is just out of this world.

We have a CCR instructor on Staff to assist you with anything you may need and our boats are CCR friendly too.

Octopus Diving can also teach Proefssional Underwater Photography courses which are perfect for the avid CCR diver.

Again, please email for more information.

Thanks

Teamoctopus.

 

[sam1]

Last week I did my "try dives" of the Poseidon Discovery Mk VI rebreather in St. Martin with Octopus Diving. (I had no previous experience with rebreathers, other than reading about them.)

My instructor, Chris, skipped most of the "theory" because from our previous conversations, he knew I already knew most of it. We started with him assembling the unit and then putting it through its power up self tests. We got on the boat and I put the unit on---nice and (relatively) light! I did two dives: the first to a maximum of 32 feet for 49 minutes and the second to a maximum of 26 feet for 47 minutes.

Buoyancy. I adapted pretty well to exhaling through my nose to vent gas. That said, I used my hands to maneuver more on these dives (particularly the first one) than in about a year of open-circuit diving! Learning curve: I used (mostly vented) half as much diluent on dive two as on dive one.

The work of breathing was harder than I anticipated and I did not notice that the gas was warmer than on open circuit. (But note that this was my first rebreather experience.)

The coolest aspect of diving the rebreather was the fishes' (lack of) reaction to me. At one point, we came up on a small school of a dozen or so fish and Chris motioned for me to swim towards them while he stayed back. (He was on open circuit.) The fish did not scatter but let me swim right up to them. Cool!

About 35 minutes into the second dive the system went into error mode. I do not hear so well above the water's surface and even less so underwater---I do not hear any of the sounds my dive computers make. But I heard this one! It was a "C1 error" (lack of confidence in the O2 sensors) and the display said "Abort!" Chris, who has over 100 hours on this rebreather, had experienced this error previously, and warned me that this error might happen and indicated that I should not abort but should stay at a constant depth and breathe for a while, monitor the PO2, and see if the error cleared. When I pointed the error out to him, he reminded me of what he had previously told me and I did what he recommended and the error cleared in less than one minute. (Presumably) thinking that this may have rattled me, he asked if I wanted to ascend and end the dive. I really wasn't rattled and looked at my computer that said we had been down about 35 minutes and signaled him I'd like another ten minutes, so we proceeded. After about 10 more minutes that same error occurred and we dealt with it the same way and it cleared. After that, having gotten to about 45 minutes, we ascended.

All in all, great fun and I'm glad I tried it. Now I have to figure out if I want one!

 

[teamoctopus]

Hey Sam,

Thanks for writing the review of your Rebreather experience and glad you enjoyed it.

For anyone interested in the IANTD Rebreather experience, this isn't a certification but just an experience on the MK6 Rebreather, so there is no formal classroom work,theory or exam. However, I will explain everything in detail to you before the dives.

It does make sense to read the Poseidon MK6 Manual first (but by no means a prerequisite) which you can download for free by following this link:http://mkvi.poseidon.com/downloads/MkVI_Discovery_Manual_Complete_v2.0.pdf

The Poseidon MK6 that I use has the latest V44 software upgrade which was released to reduce C1 errors, amongst other reasons. But after hundreds of hours on the unit I have found that shallow dives 30feet / 10 meters the unit will give more C1 errors than at greater depths with lower FO2's.
As long as the C1 error is monitored and PO2 remains constant (+/- 0.10PO2) I find the error clears in under a minute and the dive can be continued.

Poseidon will hopefully find a way to resolve this issue soon.

As any CCR or RCCR diver should know and understand:
1) If in doubt bail out
2) Always know your PO2

The cells in the unit had less than 2 hours use - they were brand new from Poseidon.

My advice to an in-experienced Poseidon MK6 RCCR diver would be to bail out, end the dive and dry your cells out.
Then re-start the unit and ensure that your calibration Test passes, if it does, dive the unit again. If it fails again on C1 contact your Poseidon dealer before diving again.

I have read on other forums that MK6 divers have installed a Shearwater stand alone PO2 monitor, mounted in the exhale T-piece on the counterlung. This will give an independent PO2 reading so if you do get a C1 you can at least verify the issue.

HOWEVER INSTALLATION OF THE SHEARWATER INVALIDATES THE CE CERTFICATION, WARRANTY AND ALSO MAY INVALIDATE INSURANCE so please be aware of this. I have no independent PO2 verification.

The Poseidon MK6 is an awesome rebreather, I have had some really amazing dives on it and would highly recommend it to anyone. I just hope that Poseidon release the DECO software and hopefully the Trimix version soon and also a way of getting rid of these annoying C1 errors.

So thanks Sam, get a Poseidon MK6 and I look forward to teaching you in St. Martin very soon!

Poseidon MK6 / MKVI CIS Lunar Discovery Recreational Rebreather | Octopus Diving | Scuba Dive & Snorkel Saint Martin

 

[audission]

Hi all,

Chris at Octopus has shared a few thoughts on his Mk6 here:

Why I dive a Poseidon Rebreather | British Diver

 

[TSandM]

Man, I didn't read this when it came out, but this scares the dickens out of me -- the machine gives me an error message that it doesn't trust the output of the O2 sensors, and I'm supposed to use THOSE VERY SENSORS to "monitor" my ppO2 until the error message clears? Yikes!

 

[M_Bipartitus]

There are several levels of sensor confidence on the Mk6, ad C1 is not the lowest. While bail-out and calling the dive never a bad choice, the advice to wait a short time to see if the the error clears could be acceptable. Not only are there two cells, but the PPO2 should not change too much over a short wait. This error shouldn't clear unless the unit has regained confidence in the cells. In this case the only loss of confidence could have been due to signal noise and not actual cell condition.

**** Speculation section ****

It's plausible that the something like the sensor's reading or response time could be erroneous if the loop pressure was changing rapidly during the test, but later be within the acceptable range if the diver was calmly hovering at a stable depth. In such a situation, the controller could regain confidence after a later test. One would expect the fractional pressure (and thus PPO2) changes to be most at shallower depths, which could explain the increased C1 occurrences above 30 feet.

While I don't know, I can only speculate (based on the thought that appears to have gone into the unit's software design) that, having lost some confidence in one of the sensors, the unit would use the more reliable sensor for PPO2 control while the error is in effect. However, it might be interesting to know more about the internal error handling of the unit. In most cases the design appears to follow "tell the user what to do and make the best of things if they don't do what they are supposed to."

 

[DwayneJ]

Man, I didn't read this when it came out, but this scares the dickens out of me -- the machine gives me an error message that it doesn't trust the output of the O2 sensors

IMHO - The Poseidon would be a great rebreather for recreational shallow resort diving where everyone in the group is diving the same type of unit. This unit does everything for you and if the electronics sense a fault, the unit flips to OC and the dive is over.

The "manual" rebreather I own requires me to monitor the health of the unit and to make sure it is functioning correctly and as training dictates - if in doubt, bail out. I believe this type of unit is more applicable for boat diving and mixed teams of OC/CCR and mixed model CCR's. Additional onboard redundancy allows you to make an educated decision to continue a dive or bail out.

As an example, I have three independent PPO2 monitors (standard is two) and I have 4 PPO2 sensors (standard is 3 and I could add a 5th). A bad sensor or a bad monitor does not impact a dive or a dive trip.

I'm supposed to use THOSE VERY SENSORS to "monitor" my ppO2 until the error message clears? Yikes!

The Poseidon should flip to bail out and the dive would be over. Regular rebreather training is pretty detailed and covers loss of instrumentation or instrumentation validation scenarios - Response is straight forward.

Dwayne

 

[Gill Envy]

nothing like a warning system that one is encouraged to ignore... I think I'll continue to rely on the voting logic and set point controller between my ears thank you :~).
g

 

[M_Bipartitus]

nothing like a warning system that one is encouraged to ignore... I think I'll continue to rely on the voting logic and set point controller between my ears thank you :~).
g

I don't see much difference between the user making and informed choice to "wait and see" if some specific errors clear and having voting logic ignore a cell for you. If you have one of three go bad and the other two are reliable, voting logic keeps you relatively safe and it may not be necessary to bailout. Both situations involve an error and either you or the controller ignoring it. With two cells out of three, You should know that there is an error (after reading all three PPO2s), yet you can choose to have the controller ignore it based on the other cells. Likewise, if you suspect a discovery controller's error is only transient and the controller may regains confidence in a suspect cell, there is little reason to call the dive immediately.

I'm aware that you are an experienced rebreather diver, but the unit is not designed for very experienced divers. This unit is such that a diver should be safe just about any time they follow the controller exactly. This philosophy leads to a controller that may be much more conservative in it's determination of what is dangerous than an experienced diver. If you know that for you, in the current situation, the error is not necessarily serious, then you can choose to ignore and reevaluate later. I suspect you are qualified and experienced enough to make decisions like these. However, the typical resort diver, who has only take recreational-level classes, may not be experienced enough to make those decisions. If the above instructor told sam1 to wait and see if the error cleared, he must have been confident that sam1 was capable of understanding the conditions and handle the decision to wait and see or bailout.

 

[francousteau]

I don't see much difference between the user making and informed choice to "wait and see" if some specific errors clear and having voting logic ignore a cell for you. If you have one of three go bad and the other two are reliable, voting logic keeps you relatively safe and it may not be necessary to bailout. Both situations involve an error and either you or the controller ignoring it. With two cells out of three, You should know that there is an error (after reading all three PPO2s), yet you can choose to have the controller ignore it based on the other cells. Likewise, if you suspect a discovery controller's error is only transient and the controller may regains confidence in a suspect cell, there is little reason to call the dive immediately.

I'm aware that you are an experienced rebreather diver, but the unit is not designed for very experienced divers. This unit is such that a diver should be safe just about any time they follow the controller exactly. This philosophy leads to a controller that may be much more conservative in it's determination of what is dangerous than an experienced diver. If you know that for you, in the current situation, the error is not necessarily serious, then you can choose to ignore and reevaluate later. I suspect you are qualified and experienced enough to make decisions like these. However, the typical resort diver, who has only take recreational-level classes, may not be experienced enough to make those decisions. If the above instructor told sam1 to wait and see if the error cleared, he must have been confident that sam1 was capable of understanding the conditions and handle the decision to wait and see or bailout.

Some of what you said might make sense, on first glance, but not if some thought is given to it. In post #6, you mention there are 2 cells in this unit. This isn't quiet "apples for apples" if you want to say the C1 error is similar to another unit using "voting logic" because with only 2 cells, it's either good or bad. Not much voting logic going on in that process. You seem to be saying if you get the C1 error, it's acceptable to wait it out. IMO, if the C1 error is legit and one waits for the error to clear, it could result in a hypoxic or hyperoxic fatality and so you're really rolling the dice if you decide to wait for the error to clear. In my case I dive with 4 cells (3 on one monitor & 1 on an independent monitor). If 2 got voted out, leaving me with 2 "working" cells, I'm outta there. Couldn't even imagine continuing a dive with 2 cells & then 1 of those start freaking out and waiting around to see if it settles. Doesn't matter who the intended customer of the unit is made for, to tell the user to ignore the error and wait to see if it clears, seems a bit nuts to me. Then to say that it happens "less" at depth . . . . doesn't give me the warm & fuzzies. But hey, that's just me

Franco