Review Poseidon Mk6 & Seven First Impressions

[jont2]

A review of the Poseidon Mk6 and Seven Rebreathers………

I recently had the opportunity to buy two Poseidon rebreathers, a MK6 and the Seven. Having never dove either I was interested to see the units up close after an interesting encounter with a Poseidon rep. I was very curious about performance.

Early on Poseidon was marketing the product as “like having 2 rebreathers in one”, an Incredibly silly thing to say, hopefully the marketing team that came up with that is on the unemployment line. Poseidon has since toned it down and the website does a decent job of explaining a “rebreather” however the site claims that Tech units are manual and Recreational units are automatic. Again not a very good or accurate thing to say.

Moving on we all know Poseidon to make some of the best high performance regulators in existence, The first stage they’re selling today is arguably to most failure proof in the business. Poseidon built its reputation on these regulators, I still dive them today. Poseidon’s other products have never been in huge demand here in the states (the largest and most important market in the world).

Poseidon has other rebreather projects in development and is actively looking to expand its commercial/military footprint.

Here are my thoughts and opinions on the unit:

DISCLOSURE: I have one dive on the unit, in 20 feet of water in the East River, NYC.

Pros:

1. The tech is cool, no doubt.
2. It breathes well and with OTS lungs it should.
3. The BOV/ADV is cool too, a little finicky but works very well, super easy one handed operation in any type of clove or mitten.
4. Trims well in the water, its fully automatic and its fun to dive, I thoroughly enjoyed the East River.
5. It is 100% automatic, but this is also a negative.

Cons:

1. It's injection molded plastic, while this helps keep costs down and with scale even more so it is by no means a robust unit.
2. It's a sloppy unit, it's not tidy. Cables pop straight out of the unit up high with no protection (MK6) with the Seven protection is better.
3. The way the wing and plate fit on the unit is cumbersome (MK6) and the quick release system on my Seven is more trouble than its worth.
4. The scrubber is replaced from the bottom and the SS screws used fit into the aluminum “tube” isn’t well thought out. Corrosion can be seen on both units, saltwater will accelerate this process.
5. The dil and 02 connections on the unit can be damaged due to the location of both, side by side on the highest point on the unit.
6. I can’t recall ever having see a unit with so many failure points. Most of these failure points are static and unlikely to fail but geeez this unit loves its o-rings.
7. The paddle is ridiculous. The sock needed to secure the paddle to your forearm is a necessity but its sort of like taking the short bus to school, no one wants to be that person.
8. It is 100% dependent on technology without a laptop you are DOA. That likely means a separate dedicated laptop.
9. The diver has no ability to override the pre-dive or even dive if something is a miss.
10. Cost: DGX (Dive Gear Express) is the cheapest I found online and its $11,700 with 2 solid state sensors, the M28 computer and BMCLs, other sites approach 17,000USD for the same configuration. Basic 120 foot limited units are around 7,000 and up. Everything Poseidon is expensive and upgrades and parts don’t disappoint in that regard. The prices for these units fluctuate wildly online.
11. Everything is proprietary and while this is important from a financial standpoint (guaranteed revenue down the road) it is also frustrating for anyone with experience not to mention “forced factory” service.

To be fair:

The unit does exactly what Poseidon says it will do. They completely re-thought and redesigned the approach to rebreather diving and they deserve credit for that. They want to invent a “recreational” rebreather market, all previous attempts have failed (Lungfish although a very cool unit and dare I say the Explorer….LOL), Poseidon thinks it can do better. I hope they succeed.

Final thoughts:

1) Seems MK6 was Beta for the Seven, the Seven if I had to bet, is Beta for something else. With all of this tech I do think that Poseidon is working on some very cool things (they actually are), we will see if its ever implemented, they certainly have the ability to produce something groundbreaking but financial viability is a huge obstacle…..as it is with all things diving.

2) The most frustrating part of this breather is the way everything is put together in the physical sense. The “layout” of the breather is very busy, diving wrecks with fishing line and nets could be problematic especially without the cowling or cover.

4) The idea of a recreational rebreather is the subject of debate, in my opinion for good reason. While “dumbing down” the complexities of a rebreather appears to make sense in the short term I’m not convinced that its smart long term. What I think the Seven does do is define a tangible path to tech diving in rebreather form.

 

[mr_v]

Interesting perspective. Will you take one cave diving?

 

[JackZwykle]

Interesting perspective. Will you take one cave diving?

As a Se7en diver - never EVER take it cave diving.

 

[JackZwykle]

A review of the Poseidon Mk6 and Seven Rebreathers………

I recently had the opportunity to buy two Poseidon rebreathers, a MK6 and the Seven. Having never dove either I was interested to see the units up close after an interesting encounter with a Poseidon rep. I was very curious about performance.

Early on Poseidon was marketing the product as “like having 2 rebreathers in one”, an Incredibly silly thing to say, hopefully the marketing team that came up with that is on the unemployment line. Poseidon has since toned it down and the website does a decent job of explaining a “rebreather” however the site claims that Tech units are manual and Recreational units are automatic. Again not a very good or accurate thing to say.

Moving on we all know Poseidon to make some of the best high performance regulators in existence, The first stage they’re selling today is arguably to most failure proof in the business. Poseidon built its reputation on these regulators, I still dive them today. Poseidon’s other products have never been in huge demand here in the states (the largest and most important market in the world).

Poseidon has other rebreather projects in development and is actively looking to expand its commercial/military footprint.

Here are my thoughts and opinions on the unit:

DISCLOSURE: I have one dive on the unit, in 20 feet of water in the East River, NYC.

Pros:

1. The tech is cool, no doubt.
2. It breathes well and with OTS lungs it should.
3. The BOV/ADV is cool too, a little finicky but works very well, super easy one handed operation in any type of clove or mitten.
4. Trims well in the water, its fully automatic and its fun to dive, I thoroughly enjoyed the East River.
5. It is 100% automatic, but this is also a negative.

Cons:

1. It's injection molded plastic, while this helps keep costs down and with scale even more so it is by no means a robust unit.
2. It's a sloppy unit, it's not tidy. Cables pop straight out of the unit up high with no protection (MK6) with the Seven protection is better.
3. The way the wing and plate fit on the unit is cumbersome (MK6) and the quick release system on my Seven is more trouble than its worth.
4. The scrubber is replaced from the bottom and the SS screws used fit into the aluminum “tube” isn’t well thought out. Corrosion can be seen on both units, saltwater will accelerate this process.
5. The dil and 02 connections on the unit can be damaged due to the location of both, side by side on the highest point on the unit.
6. I can’t recall ever having see a unit with so many failure points. Most of these failure points are static and unlikely to fail but geeez this unit loves its o-rings.
7. The paddle is ridiculous. The sock needed to secure the paddle to your forearm is a necessity but its sort of like taking the short bus to school, no one wants to be that person.
8. It is 100% dependent on technology without a laptop you are DOA. That likely means a separate dedicated laptop.
9. The diver has no ability to override the pre-dive or even dive if something is a miss.
10. Cost: DGX (Dive Gear Express) is the cheapest I found online and its $11,700 with 2 solid state sensors, the M28 computer and BMCLs, other sites approach 17,000USD for the same configuration. Basic 120 foot limited units are around 7,000 and up. Everything Poseidon is expensive and upgrades and parts don’t disappoint in that regard. The prices for these units fluctuate wildly online.
11. Everything is proprietary and while this is important from a financial standpoint (guaranteed revenue down the road) it is also frustrating for anyone with experience not to mention “forced factory” service.

To be fair:

The unit does exactly what Poseidon says it will do. They completely re-thought and redesigned the approach to rebreather diving and they deserve credit for that. They want to invent a “recreational” rebreather market, all previous attempts have failed (Lungfish although a very cool unit and dare I say the Explorer….LOL), Poseidon thinks it can do better. I hope they succeed.

Final thoughts:

1) Seems MK6 was Beta for the Seven, the Seven if I had to bet, is Beta for something else. With all of this tech I do think that Poseidon is working on some very cool things (they actually are), we will see if its ever implemented, they certainly have the ability to produce something groundbreaking but financial viability is a huge obstacle…..as it is with all things diving.

2) The most frustrating part of this breather is the way everything is put together in the physical sense. The “layout” of the breather is very busy, diving wrecks with fishing line and nets could be problematic especially without the cowling or cover.

4) The idea of a recreational rebreather is the subject of debate, in my opinion for good reason. While “dumbing down” the complexities of a rebreather appears to make sense in the short term I’m not convinced that its smart long term. What I think the Seven does do is define a tangible path to tech diving in rebreather form.

As a Se7en+ diver with a love-hate relationship with the unit, let me give you my 5 cents here:

1. You missed the most important con - it's a blackbox, it works amazing - until it doesn't. You can fix almost nothing yourself and then it needs the dealer - or sometimes - a shipment to Sweden. When a failure happens the unit most often will simply refuse to finish the tests and enter a "no dive" condition. (Insurance is void - equipment instructed the diver to not initiate the dive). It's not that they're not reliable - talking to people more experienced than me - they're extremely reliable (Se7en and Se7en+, Six was beta and not that reliable). The problem is when they actually fail, not that they fail often.

2. It's panicky as hell, even in 'tec' mode. Warnings and buzzes about normal things like elevated pO2 due to MAV use. In 'rec' mode it has amazing safety features, but it can be extremely limiting (it will for example sound the alarm if onboard dilout becomes insufficient for bailout and safe ascent and safety stop on it at given depth).

3. You missed the biggest pro in our eyes that made us buy it. Whether solid state or traditional cells - the unit tests itself regularly under water in "hyperlinearity test". It compares the reading of pure oxygen, diluent and depth at regular intervals (5 minutes I think). Nothing else does that. It has a diluent solenoid, not just oxygen. It gives it the ability to ensure that the cells AND the depth readings all line up and they are reliable. No other unit does anything remotely similar and for our approach to safety and diving profile is irreplacable.

4. About physical configuration or clutter - Se7en is extremely configurable. You simply inherited some messy config of the units you bought. You can have a stand, very strong cover, different CLs, handle that doubles as head and cables protector. We dive full 'tec' config with inverted tanks in 'tec' setup with MAVs from tecme, etc etc etc. You can even see it in my profile pic.

5. It is not flimsy - main body is aluminium and with the stainless steel rails cover on it's extremely durable. Sadly we had a chance to test it in two big tumbles on the sharp rocks as we mostly do shore diving. It holds its ground impressively well. Not as tough as KISS, rEVO, SF2, but I wouldn't call it delicate when in proper config (not naked).

6. Yes the paddle is funny... but it's the 'rec' option. It has the advantage of huge readable output (important for me with my eyesight) and actually the advantage of no input at all (for some dive profiles that's actually good and safe). For 'tec'-full option look into M28. It allows full underwater operation (including changing the settings).

7. You don't need a laptop - any phone will do, look for a Reef app. I've never used a laptop.

8. Protect it from the corrosion creeping from those scrubber cover bolts into the main canister. It will eventually ruin the main body. I think it's very bad design and it will rot eventually no matter how well you protect it.

9. And last but not least - the only unit so far to offer reliable, tested and long term warranty solid state cells.


Other than that - it's a very capable, automatic unit with unparalleled safety features. Which can (and will) panic and tell you not to dive.

 

[lizardland]

Cost: DGX (Dive Gear Express) is the cheapest I found online and its $11,700 with 2 solid state sensors, the M28 computer and BMCLs, other sites approach 17,000USD for the same configuration. Basic 120 foot limited units are around 7,000 and up.

Oof, that must be the worst depreciation of any unit. Don't know if it's just because it isn't a popular unit in the UK and we're awash with Inspos, but they seem to go for peanuts here on the second hand market.

 

[jont2]

Interesting perspective. Will you take one cave diving?

Personally no I wouldn't dive this unit in a cave or inside a wreck. Its a cool unit from the Tech perspective but I wouldn't become certified on the unit and for the money there are better options today.

 

[jont2]

As a Se7en+ diver with a love-hate relationship with the unit, let me give you my 5 cents here:

1. You missed the most important con - it's a blackbox, it works amazing - until it doesn't. You can fix almost nothing yourself and then it needs the dealer - or sometimes - a shipment to Sweden. When a failure happens the unit most often will simply refuse to finish the tests and enter a "no dive" condition. (Insurance is void - equipment instructed the diver to not initiate the dive). It's not that they're not reliable - talking to people more experienced than me - they're extremely reliable (Se7en and Se7en+, Six was beta and not that reliable). The problem is when they actually fail, not that they fail often.

2. It's panicky as hell, even in 'tec' mode. Warnings and buzzes about normal things like elevated pO2 due to MAV use. In 'rec' mode it has amazing safety features, but it can be extremely limiting (it will for example sound the alarm if onboard dilout becomes insufficient for bailout and safe ascent and safety stop on it at given depth).

3. You missed the biggest pro in our eyes that made us buy it. Whether solid state or traditional cells - the unit tests itself regularly under water in "hyperlinearity test". It compares the reading of pure oxygen, diluent and depth at regular intervals (5 minutes I think). Nothing else does that. It has a diluent solenoid, not just oxygen. It gives it the ability to ensure that the cells AND the depth readings all line up and they are reliable. No other unit does anything remotely similar and for our approach to safety and diving profile is irreplacable.

4. About physical configuration or clutter - Se7en is extremely configurable. You simply inherited some messy config of the units you bought. You can have a stand, very strong cover, different CLs, handle that doubles as head and cables protector. We dive full 'tec' config with inverted tanks in 'tec' setup with MAVs from tecme, etc etc etc. You can even see it in my profile pic.

5. It is not flimsy - main body is aluminium and with the stainless steel rails cover on it's extremely durable. Sadly we had a chance to test it in two big tumbles on the sharp rocks as we mostly do shore diving. It holds its ground impressively well. Not as tough as KISS, rEVO, SF2, but I wouldn't call it delicate when in proper config (not naked).

6. Yes the paddle is funny... but it's the 'rec' option. It has the advantage of huge readable output (important for me with my eyesight) and actually the advantage of no input at all (for some dive profiles that's actually good and safe). For 'tec'-full option look into M28. It allows full underwater operation (including changing the settings).

7. You don't need a laptop - any phone will do, look for a Reef app. I've never used a laptop.

8. Protect it from the corrosion creeping from those scrubber cover bolts into the main canister. It will eventually ruin the main body. I think it's very bad design and it will rot eventually no matter how well you protect it.

9. And last but not least - the only unit so far to offer reliable, tested and long term warranty solid state cells.


Other than that - it's a very capable, automatic unit with unparalleled safety features. Which can (and will) panic and tell you not to dive.

Your points above are reasonable and I'm aware of everything you mentioned except the inheritance of a messy config. The seven I have is cleaner than the 6 but in any configuration there is simply a lot going on and because of the way the unit operates you can't do things like ditch HP hoses. Many experienced RB divers get rid of HP hoses because the problem doesn't change by knowing your pressure as an example.

I havent dove with HP hoses in more than 10 years, no rebreather I have has them.

Plug and play solid state sensors are available for just about every unit today. In fact two different solutions exist, one more complex than the other.

You pointed out that it's a black box, thats spot on. Many people would be more interested if the user was able to configure the unit as they choose. Dont get me wrong the safety features of the unit are the best part of the unit but it is very restrictive and as mentioned shipping to Sweden is a deal breaker for most.

Durability is a real concern however, both of my units were shipped and very well packed however the same part on both units broke during shipment.....that plastic insert that slips into the "Can" secured by a single screw that allows the breathing hoses to have a water tight seal and attach to the can. TERRIBLE design. I spent 30 minutes online trying to find the part then discovered I had 3 spares.....why?

The point is I think it has a way to go and I disagree with the "create a dumber diver" and have the Tech save the day. We arent there yet, now this may be a path to get there but today isnt that day.

Look at our roads today? No one can drive a stick anymore, drivers arent better today as apposed to 30 years ago......they lack the education and experience.

 

[JackZwykle]

Plug and play solid state sensors are available for just about every unit today. In fact two different solutions exist, one more complex than the other.

And none of them offer any real long term reliability or warranty. I know that from a lead CCR designer I spoke to a couple of weeks ago.

Poseidon is still the only manufacturer to give years of warranty on them and has them integrated in the offer.
Their solution is based on industrial and decades-tried cells adapted to diving. And tested a decade and a half in diving by now.

Halcyon is about to release them I've heard, but they're using Greenflash. I'm very eager to see how they're doing over time (wouldn't mind a 3rd cell, why not?)

Most manufacturers still don't offer SS as standard and for a very good reason - they don't have anything that they could put long warranty on.

Durability is a real concern however, both of my units were shipped and very well packed however the same part on both units broke during shipment.....

I saw the picture. I fly with 2 units 4-5 times a year for close to 3 years now, they are just in suitcases and checked in and with all the abuse the airlines didn't manage to damage them yet.
I also drive with them at least every second weekend - they took a lot of abuse - and I haven't seen anything like it.
I would consider talking to the shipment company - it really, really should not just snap off. I know where that part is and while I believe that dropping it from height can break it - a little tap won't.
In normal travel that part is protected from all sides by top handle, cover and plate.


On dumbing down... it's a complicated topic. I'm on the side of FSD and I hate stick.