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Mike Ward
04-01-2013, 04:40 PM
This is a long post, sorry, but since actual sightings of the Poseidon seem to be rare you might find it interesting.

I bought my Poseidon because I fancied CCR, tried various units and liked this one best. Pure personal preference. It felt light on my back, was nice to breathe, weighs less than 10kg stripped for packing and I can pick it up one-handed ready to dive.

I knew it was a ‘recreational’ unit before I tried it and I wouldn’t have bothered except the guy I bought it from is both a good friend and a Poseidon dealer and assured me a full tech upgrade was on the way. It was still a leap of faith, and there was a degree of relief when Poseidon announced the tech unit and also confirmed that the price of my unit plus upgrade would be the same as buying the tech unit outright.

The standard unit comes with aluminium cylinders, but I specified mine with steel. The idea was to keep additional weight required to a minimum, and in the end I use less weight than I would with a single steel cylinder OC.

No wing is included, so I used my old DiveRite TransPac and attached the rebreather using a pair of cambands, a solution that is low-tech, low-profile, lightweight and works.

There didn't seem to be very many bits in the box when it arrived, they went together easily and the unit fired up nicely. t'internet has it that the Poseidon electronics are temperamental and will fail the automated pre-dive checks just to spite you. Not my experience so far. The only pre-start fails I've had were my fault. You can’t blame the unit if some dimwit pinches an O-ring.....

If the startup routine does fail the unit displays a code number to tell you which test failed and why - it runs something like forty tests, some of which can fail for more than one reason - then turns off. Poseidon provides a list of codes in the manual so you know what the issue was and can rectify it.

If you don't bother turning it on properly and just jump in Poseidon say the unit will hard-start and do the best it can, all the while merrily bleeping, buzzing and vibrating until you get out of the water. Haven't tried it and don't intend to.

The unit is powered by a rechargeable battery which sits at the top of the unit behind your head. It contains the master computer and is rated for 30 hours continuous operation. I found the handset display showed well over half capacity remaining after two days liveaboard diving, say 8 hrs in the water. Insert the battery in the charging station and it measures remaining charge and total battery capacity. Normally the battery simply charges up, taking an hour or two, but if the unit hasn't been used for some time or if the charger detects reduced total capacity it prompts a 'learn cycle', a complete discharge/recharge routine taking about 8 hours to complete. Poseidon say the battery will last for thousands of charging cycles.

The handset is on the end of a cable that I think is too long, but I'm only five foot seven so that might be me. I made a very snazzy (!) wrist-mount from some plastic pipe, cable-ties and bungee cord because I got fed up of continually clipping and unclipping the display so I could read it. At least I could read it, the numbers are nice and big and show the information very clearly. The downside of this, of course, is that the handset is on the big side. All in all, not my favourite bit of the unit.

The handset backlight comes on automatically when light levels drop, which means inside wrecks or even at the bottom of Stoney on a dull day as well as at night.

One oddity is that the dil and oxygen cylinder pressures are shown as a percentage of their full capacity rather than in bar, but in practice that doesn’t actually matter.
There's a red HUD which flashes red once every two minutes to prompt you to check the handset. It's reasonably visible, dependant on mask choice. Use a black-skirted mask and it's out of sight. Whenever the HUD flashes, a light also flashes in the unit battery behind your head to alert your buddy and the world at large.

If the unit detects a problem the HUD flashes continually and a buzzer sounds to tell you to take appropriate action. If the problem relates to ppO2 the mouthpiece will also vibrate. If that happens, you go OC by turning the lever on the standard fitment BOV. That's a one-finger job and the BOV breathes well in OC mode. The BOV is plumbed to the dil cylinder as supplied, so your next task will be to switch to the bail-out tin you're carrying, end the dive and ascend. That's the standard, trained response to all unit problems. Don't try to fix it, go OC and end the dive.

There is no manual oxygen add, and no way to manually add diluent except exhaling through the nose and triggering the ADV.

On descent the standard ADV works positively. Inhale and there's a slight resistance before the ADV opens and the gas addition seems steady.

The stock recreational unit is sold as air dil, but that actually means the diluent has to contain 21% oxygen. This is measured automatically in the pre-dive test routine and if it isn't 21% the unit won't start. I've been told it should tolerate up to 23%, but when I was given an ‘air’ dil cylinder actually containing 26% it refused to fire up…..

Loop ppO2 is monitored by two sensors. The output of both is checked as part of the automated pre-dive test sequence using dil and oxygen so you know the sensors are linear from ppO2 dil to 1bar. Then the primary oxygen sensor is tested automatically with O2 only as you drop below 6m, so you now know this sensor is linear to just over 1.6bar. By the time you’re at 12m the deep setpoint will have been achieved, controlled by the primary sensor, and by comparing the output of the primary and secondary sensors the unit assures itself and you that you have two sensors that are linear to the deep setpoint. After that the unit checks the primary sensor every couple of minutes with dil to make sure it’s reading correctly for the depth and also checks to make sure that both sensors are reading the same. Differences between the sensors or unexpected responses trigger alarms and you abort.

The volumes of gas used in the checking process are tiny and don't noticeably alter loop volume or ppO2.

Diving the unit you hear a regular 'shh-shh, shh-shh, shh-shh' behind your head, which is the solenoids injecting gas for calibration. In reality the sound was both a reassurance the unit was operating correctly and a better prompt to check the handset than the HUD, which I find hard to see in daylight.

Although the basic unit is recreational and intended for no-deco use only it still has a fully functional decompression computer as standard. This monitors remaining no decompression time very clearly to make sure you don't accidentally end up requiring mandatory stops. With five minutes NDT remaining a continuous flashing up-arrow (Like that on many dive computers) appears on the handset display, the HUD flashes once and the buzzer buzzes for approximately half a second. The idea is to prompt an ascent to allow the no-decompression time to flood back. Ignore the prompts and the flash and buzz are repeated every minute. If you accidentally go deeper than 40m you get a similar prompt to ascend.

If you miss the warnings and accidently slip into deco the HUD will flash regularly but the buzzer still only buzzes for half a second every minute. The unit itself continues to maintain set-point and the handset displays your current ascent ceiling and a total time to surface. Decompression algorithm is DCAP, which I can't find as a stand-alone piece of software but which seems pretty close in overall run-time to MV planner using 30/85 gradient factors, though with a very different profile.
The light built into the battery means the rest of the world can see that you’ve rather carelessly gone too deep or slipped into deco.

Surface setpoint can be adjusted to 0.4 or 0.5 bar ppO2, and deep setpoint between 1.0 and 1.3. The transition seems effectively linear with depth once you're a few metres deep on both descent and ascent. Higher ppO2 is not maintained through the shallow stops if you do accidently enter mandatory deco, but never drops below 0.9 bar until your mandatory stops are completed. A normoxic trimix battery is available that allows use of a minimum of 16% O2 and any helium fraction. This has no deco alarm, certification is to 48m and does maintain deep setpoint until mandatory deco ends.

In-water trim is nice, the valves-up configuration must help with this.

Daily strip-down, rinse, dry and re- build is straightforward, though pulling the end off the scrubber can to get to the sofnolime isn't easy. Plenty of O-ring grease helps, and there's a webbing strap to grab, but I found a rocking motion on each of the four lugs for the bolts that hold the can shut worked better. There are two sealing o-rings and once the first is clear the second comes out easily.

The unit is designed to use pre-packed scrubber cartridges. These are easy to use but more than twice the price of loose lime and I wasn't sure of getting them abroad so I bought a Tecme refillable cartridge. This has quite coarse metal mesh either end of the scrubber can so I dismantled a pre-packed scrubbed, removed the thin scrim from each and used these in the Tecme unit to avoid dust getting where it wasn't wanted.

Scrubber duration is officially 3 hours in 4 degree water. Poseidon recommends filling the oxygen cylinder to 130 bar so at ‘average usage’ the oxygen will last as long as the scrubber and you change both at the same time. Filling O2 to 200 bar didn't seem to cause any issues, but the display shows the O2 cylinder as 'full' unitl the pressure drops below 130 bar. Odd until you get used to it.

First stages have a standard DIN thread on the dil and the M26 on the oxygen, so I needed an adapter and then used standard 3l Inspo tanks abroad, and I carry the adapter just in case in the UK. I'll swap that out, probably.

I've had one leak, caused by the mouthpiece cable-tie coming loose. I couldn't believe the amount of water something so trivial allowed into the unit, the scrubber can was half-full.

It's an easy unit to dive and I'm very happy with mine. It’s nine months old, got 50 hours on it, split between the UK and the Red Sea, and still looks like new, give or take the odd scratch on the face of the display.

Chris Thomas
04-01-2013, 04:52 PM
Nice report!

Mark Chase
04-01-2013, 05:08 PM
Love the travel weight

Not a fan of intrusive electronics but if they are reliable its no so bad.

ATB

Mark

Pete Bullen
04-01-2013, 05:51 PM
Thanks for that, good report and useful info.

Dyson Diver
04-01-2013, 06:02 PM
interesting read ,, keep the handset out of direct sunlight too , they turn black if they get hot ,,, then you have to cool them down before you can read them again , easier to keep it covered up.

timmyg
04-01-2013, 08:37 PM
Thought I would post this. I don't dive one however my mate has just purchased one new for £4000. Apparently a special offer so I thought I'd add this in case people were interested in buying one. I'm not sure the ins & outs however speak to Mark Rowe on here (sorry dude) & he may be able to give some more information. Only 100 available apparently.

Linky (https://www.facebook.com/#!/photo.php?fbid=270855186376658&set=a.216223581839819.48164.211042445691266&type=1&theater)

TG

matt
04-01-2013, 08:50 PM
Nice, glad you're enjoying it - it's what it is all about!

Matt.

Ruffy
04-01-2013, 09:12 PM
Good report!

Mark Rowe
04-01-2013, 09:49 PM
Nice report Mike. From TimmyG I've secured the first of the 100 discounted mk6 units at £4000 so great discount. Need to find an instructor now - already inspo qualified.

iamyourgasman
04-01-2013, 10:57 PM
Nice report Mike. From TimmyG I've secured the first of the 100 discounted mk6 units at £4000 so great discount. Need to find an instructor now - already inspo qualified.

Give a call to Neil at Bristol Channel Diving. Can't go wrong with him! http://www.bristolchanneldiving.co.uk/home

Frappawotsit
04-01-2013, 11:05 PM
Dive in - Gildenburgh are also a Poseidon mkVI School, so I'm sure could assist.

(near Peterborough)

Mark Rowe
05-01-2013, 12:23 AM
Thanks already been speaking to Neil ref CCR.

Mike Ward
05-01-2013, 09:46 AM
That pricing move is very interesting. I wonder if it's a pre-emptive response to the Hollis Explorer, also priced at four grand. I assume that's pounds but I don't know.

Mark Rowe
05-01-2013, 03:13 PM
Can't say what the hollis will be - speaking to Simon @ Poseidon they are on a push again at the rec level market. It maybe because hollis are incoming shortly, it maybe because they aren't shifting enough units. Don't know or care. I'm happy to have saved money on a CCR that was on my short list - travel with it is a big factor. 8kg minus scrubber & cylinders
For me the draw of full tech mod 3 CCR is less of a must have - I'm already inspo 40m + deco qualified and that was on my list too. But actually how much diving do I - anybody do, below 60m, as a normoxic diver it ain't that much, for me anyhow.
The trimix 48/60m batteries will get purchased but I am unlikely (today) to go to the max depths of the unit, but more likely to want decompression as required.
2013 seems like a good time to go to a Mk6 as the tech upgrade path may provide other partial upgrade options this year too.

Mike Ward
05-01-2013, 03:22 PM
Can't say what the hollis will be - speaking to Simon @ Poseidon they are on a push again at the rec level market. It maybe because hollis are incoming shortly, it maybe because they aren't shifting enough units. Don't know or care. I'm happy to have saved money on a CCR that was on my short list - travel with it is a big factor. 8kg minus scrubber & cylinders
For me the draw of full tech mod 3 CCR is less of a must have - I'm already inspo 40m + deco qualified and that was on my list too. But actually how much diving do I - anybody do, below 60m, as a normoxic diver it ain't that much, for me anyhow.
The trimix 48/60m batteries will get purchased but I am unlikely (today) to go to the max depths of the unit, but more likely to want decompression as required.
2013 seems like a good time to go to a Mk6 as the tech upgrade path may provide other partial upgrade options this year too.

Pretty much my reasoning as well.

As regards upgrades, I understood there was the 40m deco battery (Which I cannot for the life of me see anyone buying), the normoxic trimix 48m 16% battery and then the red battery is part of the full 100m CE certified tech upgrade - is Simon definitely saying there is another option?

Nitnab Nhoj
05-01-2013, 03:29 PM
I'm off to Cocos with a new Rec to Tec CCR. More info when I'm allowed.

Mark Rowe
05-01-2013, 03:31 PM
The red battery Simon said was 60m - cant say whether it is on the tech too and full 100m trimix. Also think some manual control is perhaps of benefit at great depth. However I think CCR incidents may reduce if
1 the diver bailed out to OC (a known gas source) instead of manually flying it, trying to continue the dive even.
2 carried enough OC bailout to support 1 above for the planned dive.

For me the 'I'm a bust CCR - bailout and go home' model by Poseidon is one I like.

matt
05-01-2013, 03:38 PM
travel with it is a big factor. 8kg minus scrubber & cylinders

How easy are the scrubber and cylinders to get hold off? Cylinders same as Inspo? EAC?

Matt.

Mark Rowe
05-01-2013, 03:41 PM
Depends on location I know of people using inspo cylinders and in UK I will get a pair of steel ones too - less weight else where.
The lightweight option when in Sharm etc in a shorty really appeals too though.

matt
05-01-2013, 03:42 PM
I was wondering mostly about the EAC availability. I assume you can get them now like you can lime, otherwise no advantage for travel.

Matt.

Mark Rowe
05-01-2013, 03:56 PM
Like any CCR traveller location would depend on them supplying the required items, can't supply - ain't coming as a CCR diver. I do like OC too though.

matt
05-01-2013, 04:06 PM
10 years ago getting HP O2 and Lime was difficult - now it's almost standard with at least one operator in almost all locations. Not sure about EAC's and not bumped into anyone who knows either so seems like a risk at least.

Matt.

Mike Ward
05-01-2013, 04:19 PM
10 years ago getting HP O2 and Lime was difficult - now it's almost standard with at least one operator in almost all locations. Not sure about EAC's and not bumped into anyone who knows either so seems like a risk at least.

Matt.

That's one reason I bought an aftermarket refillable scrubber that uses ordinary, easily available lime. I used hired 3l Inspo cylinders on my Red Sea liveaboard.

matt
05-01-2013, 04:24 PM
That's one reason I bought an aftermarket refillable scrubber that uses ordinary, easily available lime. I used hired 3l Inspo cylinders on my Red Sea liveaboard.

Is that a tested modification or just something you've done? I know someone (probably Paul) did some EAC versus loose pack tests for APOC and I thought the WOB and Endurance was badly affected. I'll look for the thread but won't move the material from its current home.

Matt.

matt
05-01-2013, 04:39 PM
I found the thread. 23% increase in WOB on APOC test by PaulR when moving from EAC to granular (result was still inside CE parameters but change was quite significant). Endurance went up by 15%.

Probably not relevant for the Poseidon as I just remembered they do not use EAC but rather they use SofnoDive - which is 797 pre-packed. I'd still be cautious if it's a none approved mod though.

Matt.

Mike Ward
05-01-2013, 05:41 PM
I found the thread. 23% increase in WOB on APOC test by PaulR when moving from EAC to granular (result was still inside CE parameters but change was quite significant). Endurance went up by 15%.

Probably not relevant for the Poseidon as I just remembered they do not use EAC but rather they use SofnoDive - which is 797 pre-packed. I'd still be cautious if it's a none approved mod though.

Matt.

I can't feel any difference in the WOB, though I'm aware that means little. I've seen a WOB comparison for a different aftermarket scrubber but not for the one I have, that unit was either the same as the standard pre-packed cartridges or slightly better.

Mine came from Tecme in Germany, Rebreather, Parts, Service, unique solutions (http://www.tecme.de)

Mark Rowe
11-01-2013, 10:41 PM
Just finished cross over course at NDAC with Neil Block. Really good two days and complained to an AP Vision a lot easier to live and dive with. I like the box a lot and found trim easy to get and buoyancy was good 99% of the time. The handset is easy but information cycles in loops which is a little different to begin with. I dived it with steel backplate, OPH and 50ibs wing and ali80, needing 14kg of lead, 8 on the belt and 2 in a halcyon weight pouch attached each side of the canister housing using the upper of the two 3 liter cam bands. All sounds a lot but the counter lungs add a lot of positive buoyancy.
Might write more if interested.

nickb
11-01-2013, 10:56 PM
needing 14kg of lead, 8 on the belt and 2 in a halcyon weight pouch attached each side of the canister housing using the upper of the two 3 liter cam bands. All sounds a lot but the counter lungs add a lot of positive buoyancy.14kg? :eek:
How do the counter lungs add a lot of positive buoyancy? Sounds like you need to get a handle on the concept of 'minimum loop'.

Mark Rowe
11-01-2013, 11:00 PM
Sorry cant count 8 + 2+ 2= 12
They are, however the smallest counter lungs going. Only come in one size and are quite full to supply me a lungful.

iamyourgasman
12-01-2013, 08:44 AM
Nice to see someone else actually diving the units apart from Neil LOL. Joking aside, it was nice to meet you on Thursday and glad you have enjoyed the MK6. I'm with Nick: even 12kg sounds rather lot! But I have started with 6kg on the rEvo and now as I'm more comfortable I have discovered that I'm negative even without any (in fresh water).

Mark Rowe
12-01-2013, 05:07 PM
Nice to see someone else actually diving the units apart from Neil LOL. Joking aside, it was nice to meet you on Thursday and glad you have enjoyed the MK6. I'm with Nick: even 12kg sounds rather lot! But I have started with 6kg on the rEvo and now as I'm more comfortable I have discovered that I'm negative even without any (in fresh water).

Agreed but I will play with the weight myself. I was in a trilaminate suit with lots of under cloths as my O3 was in the the shop for new boots and neck seal. When we did the 40m dive with ali80 and my canister torch I did feel very over weighted, and didn't like it.
Looking back at my inspo course at Bovisand I started with 12kg (with 3 ltr steel bailout too) but wrote in my log book that it was too much.
I think minimum loop volume is not an issue - I could hold a 3m stop with ease on the first dive and that never happened with the inspo either. It's a lovely unit to dive and trimming out is easy too.

As I have another 7 canisters to blast through hours will be coming thick and fast - especially if I go out to Dahab in a couple of weeks for my tec instructor crossover

Mike Ward
16-01-2013, 09:40 AM
I was told to expect to use a lot of lead because the unit was very buoyant, but I've ended up with the same weight I'd use to dive single steel cylinder OC, about 8kg total. No backplate so it's all on a weightbelt at the moment but that's something I need to resolve asap to spare my lower back.

I'd be very interested in anything else you wanted to share about diving the unit!

Mark Rowe
16-01-2013, 05:04 PM
Steel inspo cylinders spread the weight up the unit which helps but I have only used them on one dive. I had a steel BP and the wing could have been smaller - apparently a 30 Ilb wing is enough so trying my WTX3 next dives. I had no issues with trim on the unit and much easier than the inspo which has you stuffing weight into the top of the box. I'm going to move the 2x2 blocks that were on the upper cam band to their own cam band at the top of each Ali cylinder, tucked in tight ( if possible) to the back plate to low the centre of gravity.
Ordered a pack your own scrubber from tecme as I'm may be moving to Dominican and canisters might be a problem - and also much cheaper to run.
Roll on to when the new 60m trimix battery comes out as I don't want the 48m and the 60m albeit I'm sure Poseidon would want me to buy it.
http://img.tapatalk.com/d/13/01/17/2u7a2e8e.jpg
Happy Diver.

Mark

Mike Ward
17-01-2013, 12:46 PM
Cheers Mark.

FYI I changed the hose to the BOV for a shorter one to make it neater.

Ruffy
17-01-2013, 09:59 PM
Cheers Mark.

FYI I changed the hose to the BOV for a shorter one to make it neater.

Or just thread it under your loop hose behind the shoulder port:)

Mike Ward
18-01-2013, 08:31 AM
Or just thread it under your loop hose behind the shoulder port:)

The shorter hose doesn't catch on holes in wrecks though :cool: