Am i missing something--question for caveseeker7 and other RB gurus

[hoopa]

First off a hello to all that read this

Ok-- So here goes---- I surrender, i give up-- put me in coach--- I want to join the ranks of no-bubble divers and start rebreather diving....

I have been reading my tail off on both here and the decostop trying to learn all i can about different rebreathers.. After reading all the hype and facts i still have a few questions.

The unit that seems to offer the most from what i can tell is the Prism
5-6 hours of bottom time
heads down display
300+ max depth
light weight (47-51lbs)
seems to be pretty small in size
battery out of the loop so as to not affect o2 if it gets wet
analog back up o2 readings

so with all that said why arnt more people using them? Yes i know they are pricey($7800 usd) but seems like you get alot for that money.

What is the down side that i am missing?
Hard to get parts?
Is the owner of the company a jerk?(doesnt seem that way-- seems like a good guy)
Anything i cant think of?
very hard to work on yourself (people are talking about how easy the sport kiss is to work on ect)

I see alot talking about the new sport kiss and evolution but i dont understand what im missing--- all love the sport kiss yet the prism isnt much bigger or heavier-- with twice the depth and bottom time rating-- it would seem to me i would rather have the extra bottom time on my side for things if they (god forbid) go wrong ect.

The only down side i have read about so far is that the Prism takes alot to get ready for a dive( a big check list) -- is this true? Im not looking to spend a hour going through a check list each time im going to jump in the water.. and is this where the sport kiss or classic kiss excels over the prism? Or was the pre dive check just over stated by some?

Here is what i read on one site about the pre check on the prism
"Preparation of the Prism seemed to take a lot longer. In fact, prescribed pre-dive preparation could take the best part of an hour. But it does make it very safe and, with five hours' duration, you don't have to prepare so often."

Im looking to use the Rb i end up with for all types of diving (from play dives to cave) Im just trying to do homework to find out the best overall rb that will work for just about any situation.

Would love to hear all of your opinions on why the prism is good or bad --what would be a better option and why(list facts not just "i like mine better"-- why do you like it better?)



ps -- Is there anything out there that is truly worth waiting for?-- I hear about the oddessy from diverite-- Any specs out for that yet?


thanks all --hoopa

 

[DiveTub]

Gday Hoopa
Just from a pretty new RB diver myself, the biggest problem is delivery times for the PRISM. Peter and Shas have really just been a smallish operation up until now producing a much smaller number of RB's than say AP Valves with the Inspiration.

Steam Machines has in fact just relocated to new premises in Tennessee. So they can keep up with the huge demand and shorten waiting times for the PRISM Topaz.

A Group of us in Australia placed an order middle of last year for 10 PRISM RB's, we are expecting delivery towards the end of Feb to early March, the biggest hold up was the move of Steam Machines, if they had not moved so soon we would have seen the units in November. I believe they are now fully up and running with production as of the end of December.

Like yourself I did a huge amount of reading and research before deciding on the PRISM, in the end I was swayed by build quality, weight and price, I found it perfect for the type of diving I do

The KISS was also attractive but for the difference in price I went the ECCR option as oppose to the KISS system. I have friends that dive the KISS and love them, it suits the diving they do, and they can concentrate on flying the unit.

I do a lot of photography I prefer to concentrate on the subject than having to monitor gauges on my arm, having an ECCR and the HUD just works better.

As for an hour set-up I tend to do 5 hours of diving every weekend, so a single set-up on Friday night then I am set for the whole weekend.

Anyway we are training on the units third week of march and I will be writing a full report on my first impressions of the PRISM Topaz

Good luck with your research

Cheers
Chris

 

[padiscubapro]

A couple of points..

Everyone has an opinion on rebreathers what one person considers a plus another may consider that same thing a fault. I wount get into that here, but just say alot of people differ on what is the best way to do things.

I wouldn't count on 6 hours out of a Prism, but I'm not saying those runtiimes aren't possible with people doing long decos of doing nothing...
At normal work loads 5 hours is reasonable for most divers, if we scale the ratings of some other rbs to the test parameters used for rating the prism, units that claim 3 hours at 1.6 lpm of co2 will give around the same run time.. Obviously packing, the chemical used, and workload will determine actual results..

Small company means long wait time, most people dont want to wait.. APD in a good month probably produces as many units as SMI has produced in total.. Same goes for companies like innerspace systems(they have produced around the same ammount of units as SMI).. Also since there are more inspirations out there that means a) parts are more readily available, b) you are more likely to see another person with the rig, c) used units are frequently available making the spread easier.. d) alot more instructors - This is a big point

People buy what they see..

Jetsam is starting to produce rigs much quicker (adding up both the classic and sport models that should have passed SMI and innerspce on total units), the sport unit will probably sell well since its parts will be able to be mass produced and its very compact.

My personal rig is a hodge podge of alot of different components.. There probably isn't another rig like it around.. I built a rig that I felt fit MY opinion of what works best, that most definately will vary from another individuals opinion what works best.

For example I chose what I though was the best current electronics available (the HH), next I had a custom titanium chasis made (my rig can take extreme abuse), a dual OMS bladder, I have a dsv/oc from poland which is well manufacturered(althoug the Divematics are probably the nicest units), an Inspiration lower cannister and co2 cartridge (soon to be replaced with a flood recoverable radail scrubber with a very long duration), currently inspiration counterlungs (soon top be replaced with a custom set from innerspace ( I already tried counterlungs with the same design as the prism), inspiration harness (soon to be replaced with a custom harness from Oxycheq).

 

[Curt McNamee]

First off a hello to all that read this

Ok-- So here goes---- I surrender, i give up-- put me in coach--- I want to join the ranks of no-bubble divers and start rebreather diving....

I have been reading my tail off on both here and the decostop trying to learn all i can about different rebreathers.. After reading all the hype and facts i still have a few questions.

The unit that seems to offer the most from what i can tell is the Prism
5-6 hours of bottom time
heads down display
300+ max depth
light weight (47-51lbs)
seems to be pretty small in size
battery out of the loop so as to not affect o2 if it gets wet
analog back up o2 readings

so with all that said why arnt more people using them? Yes i know they are pricey($7800 usd) but seems like you get alot for that money.

What is the down side that i am missing?
Hard to get parts?
Owner of the company a A-hole?
Anything i cant think of?
very hard to work on yourself (people are talking about how easy the sport kiss is to work on ect)

I see alot talking about the new sport kiss and evolution but i dont understand what im missing--- all love the sport kiss yet the prism isnt much bigger or heavier-- with twice the depth and bottom time rating-- it would seem to me i would rather have the extra bottom time on my side for things if they (god forbid) go wrong ect.

The only down side i have read about so far is that the Prism takes alot to get ready for a dive( a big check list) -- is this true? Im not looking to spend a hour going through a check list each time im going to jump in the water.. and is this where the sport kiss or classic kiss excels over the prism? Or was the pre dive check just over stated by some?

Here is what i read on one site about the pre check on the prism
"Preparation of the Prism seemed to take a lot longer. In fact, prescribed pre-dive preparation could take the best part of an hour. But it does make it very safe and, with five hours' duration, you don't have to prepare so often."

Im looking to use the Rb i end up with for all types of diving (from play dives to cave) Im just trying to do homework to find out the best overall rb that will work for just about any situation.

Would love to hear all of your opinions on why the prism is good or bad --what would be a better option and why(list facts not just "i like mine better"-- why do you like it better?)



ps -- Is there anything out there that is truly worth waiting for?-- I hear about the oddessy from diverite-- Any specs out for that yet?


thanks all --hoopa

Hi Hoppa- Curt here in Seattle. I just wanted to share with you what I have gone thru in the last six months. I am a tri-mix diver and have been diving since 1970. I love technical and wreck diving. Lately, I decided that I was ready for some new challenging and exciting activities. I am also a pilot and just sold my airplane. The technical diving that I do consumes almost all my spare time. It has been a great change for me and has added spice to my life that flying use to give me.

I decided to look into the whole RB thing. I had been to DEMA and looked at units. I had done all kinds of research that we all seem to go thru, spoke to a lot of people and looked at all the units currently out there. All you can do is make a decision that makes since for you based on the information that you aquire.

For my reasons and what I like, I purchased the KISS Classic. I liked the idea that it was built very tough, that it has minimal electronics and moving parts to fail, simple to operate and the manufacturer is close by with great customer support. The unit is also designed to be maintained and repaired by its owner. Their is nothing that I cannot fix on my unit. I carry a few spare parts in case I have a problem on a dive trip. The unit is very simple and not much to go wrong.

Two months ago, I went through my training and now have about 30 dives on my unit. Last weekend I dove the wrecks and walls in Naniamo, BC and had a great time. I can now see why CCR diving is so great for all the reasons everyone has been talking about. My girlfriend also has a KISS Classic and will be a KISS instructor soon. She has over 100 dives on her unit and has had it down to 215 feet on tri-mix. She is also an underwater photo nut. She takes hundreds of pictures on every dive that we go on. She has had no problem doing that and diving the KISS. When the unit is set up properly, at depth all you need to do is add a shot of 02 to your loop every 15-20 minutes.

The unit has some great features like your back up regulator being build right into the mouthpiece. If you have a problem, all you do is twist a valve on your mouthpiece and you are now on OC. Very simple, quick and safe.

We love are units and are very glad that we purchase the KISS Classics and totally believe in the design. My girlfriend went up to the factory in Vancover, BC and met the owners, Gordon and Kim. They are great people and very active in CCR diving. Their goal is to supply a great product with great customer support at a good value. I feel that they are doing that.

Well, its time to for me to get my KISS Classic ready to go diving. It is a very simple process and takes only a few minutes. I am going on a dive boat today to do some diving in the South Puget Sound. My unit can go 4 hrs on the scrubber, and the 19 cu ft diluent and 19 cu ft O2 will last a much longer than that, so I am set for a full day of just about any type of diving I want to do.

See you later and hope you jump into the great world of CCR diving no matter what unit you get.

Sincerely,

Curt
flyingcash@hotmail.com

 

[silent running]

Hello Hoopa, I'm a Prism owner and I have 225 hours on the unit. And obviously I think it's the best rebreather out there. I've traveled with it many times and it's preformed flawlessly-never missed a dive. The set up time is not much different from any other unit- they all require scrubber packing, pressure tests, sensor cal etc.. with a little experience this time becomes a matter of minutes, not hrs. The Prism scrubber takes a little more time to pack, but it breathes easier and lasts longer than any other unit. In warm water it will do at least 6hrs. Your real choice is between the different design philosophies. Back mounted lungs? Over the shoulder lungs? Manual control ppo2? Or electronic control ppo2? Finally you should look carefully at who has tested their units and under what circumstances the testing was done. The work of breathing is also a very important factor. After diving the Dolphin for many hrs which has back mounted lungs, I will always prefer the ease of breathing over the shoulder lungs. Try to find a way to get some pool time in with as many units as you can.

 

[scubahubby]

Hi Hoopa,

All rebreathers are flawed and have drawbacks. Rebreather design is basically making a series of tradeoffs. All the CCRs in production and available (Inspiration, Meg, Prism, Kiss Classic & Sport,...) have their unique advantages and disadvangages. You have to decide what type of diving you are really going to be doing and what you really care about.

I shoot video (and I am starting to do stills) underwater and it only took one dive on an over the shoulder counterlung CCR to convince me I did not want them. Too cluttered and restrictive *for my tastes*, particularly when diving with a camera or camcorder.

I was also not interested in units not currently in production which ruled out the Mk 15, 15.5, 16 line and left me with the KISS Classic (this was before there was a Sport) as the only option for back mounted counterlungs.

It is also the case that I do computers and software for a living, and I had a strong preference for a non-electronic control CCR (unless I built the computer and wrote the software! <just a little arrogance but alot of realism>). However shooting video means I also do not want to have to too much time controlling the unit. Again, for me, the KISS was the solution. Its manually controlled but the constant bleed orifice greatly reduces how often you need to manually add O2. But if I was not shooting video, in all honesty I would have taken a more serious look at the meg, prism, and inspiration.

Finally, I was switching to CCR because I was about to start tech diving training (trimix etc) and CCR, for me, just makes much more sence for deep diving. So my experience was mostly in the 50m range and relastically it was going to be a while before I was experienced enough to be diving in the 100m range. And thus a while before I would know if I was actually going to persue even deeper diving. So the 100m depth limitiation of the KISS classic was only a potential future issue. In fact there are mods you can do to take it deeper, but when I am actually diving in the 100m range only then will I know what I consider the necessary features for a CCR for diving at that or deeper depths.

So for me it was an easy decision. Where easy = almost a year of investigation & talking to CCR divers and doing some training on one model before making up my mind. The lower price of the KISS was the final nail in the coffin for me.

My advice is to figure out what type of diving and depths you are honestly most likely to be doing. Then keep asking questions and talking to people. And try to get try out dives on as many units as you can.

Bottom line, come over to the dark side! I really dislike OC diving now and can not imagine switching back full time.

- Ozzy

 

[BigJetDriver]

Would love to hear all of your opinions on why the prism is good or bad --what would be a better option and why(list facts not just "i like mine better"-- why do you like it better?)
thanks all --hoopa

Hoopa,

I dive and teach the Inspiration and a military r-b. I know, however, that the Prism is a good unit (almost bought one). The guy you want to PM for the full story on it is Caveseeker7 (Stefan). He'll give you the best run-down.

Cheers!

Rob Davie

 

[caveseeker7]

... and I apologize. Hi hoopa.

The unit that seems to offer the most from what i can tell is the Prism

There are CCRs out there that offer more bells and whizzles (and buzzers) than the Prism, with a few more on the way to join the pool.

What the Prism has, however, is excellent engineering in all the basics:
Weight, size, capabilities, WOB, user friendliness and safety.
It is probably simplest and most transparent eCCR on the market.

5-6 hours of bottom time

That is correct, the cannister is rated at 300 minutes.
Six hours are attainable depending on depth and temperatures during dives, as are longer times. In regards to padiscubapro's post, it is correct that NAVY protocol differs from CE protocol. The NAVY tests with a CO2 addition rate of 1.35 liters per minute whereas 1.6 lpm are used for CE testing.

That means that the Prism scrubber can absorb 405 liters of CO2.
Joe's Inspiration can absorb 288 liters of CO2, the upcoming Evolution managed 192 liters to get its CE aproval. The Ouroboros should be able to absorb 240 litres of CO2, same for the SportKiss asuming its rating is based on CE protocol (which makes sense as Jetsam wants to pursue CE certification). I don't know what what sort of testing has been done on the Classic Kiss or the Meg. So even when you consider the difference in protocol the Prism beats the competition hands down.

Usually at this point someone throws the fact that the Prism has a larger cannister into the ring. Aside from the obvious 'So what, yours doesn't come with a larger scrubber' even if you go by liters-absorbed/pound-of-material the Prism comes out ahead by almost 20%, In other words it has a very efficient scrubber. Good basic engineering.

The only CCRs I'm aware of that has a longer duration based on available independent testing are the ones equiped with MK16 center sections, which absorb 454 liters CO2 (although they were tested to 1.0% CO2 loop content rather than CE and current NAVY limit of 0.5%).

heads down display

Yes, and a good one at that. Doesn't just give you setpoint info but also warnings for low battery and cell problems. Unlike any currently available model, the Prism has cell verification that tracks the cells in order to distinguish one or two cells failing vs. two or one being good. This eliminates the injection of O2 into the loop due to failure of two cells and the correct getting voted out. Good basic (software) engineering.

light weight

That's correct, the Prism is the lightest eCCR afaik. The low weight does have the drawback of having less negative bouyancy, though. But I rather add a few pounds of weight for the dive than have to haul it around as part of the rig.

seems to be pretty small in size

The standard tanks are 3 liter tanks like the Inspiration's, so in size the Prism is closer to that unit rather than the SportKiss.

battery out of the loop so as to not affect o2 if it gets wet

Again, that's good basic engineering, there is absolutely no intelligent explanation to do it any other way. Personally, allowing the battery into the loop is a major safety oversight in the CE regulations.

analog back up o2 readings

That was one of the deal breakers for me. Having an O2 monitor independent from electronics and battery. A major safety factor that allows truly manual control of the rebreather.

so with all that said why arnt more people using them?

I asked myself the question. Marketing most likely. Publishing the test results was appearantly not enough. However, there are plenty of people using Prisms, they're just not a very vocal crowd. At least not on the boards.
You'll find plenty of divers use them professionally, for example in research.
I'm not sure from where padiscubapro has the manufacturing numbers of SMI, ISC, APD and Jetsam.

Yes i know they are pricey($7800 usd)

The price is about average for an eCCR, considering that the Prism has no options but the cowling. ADV, HDD etc. are all standard, and with the Evo-electronics equiped CCRs approaching (if not passing due to the exchange rate) the $10K mark and a well equiped Meg being in that same neighborhood the Prism might just turn out to be a bargain.

Hard to get parts?

I'll let Shas Readey answer that. You know she's on the board here, don't you?

Owner of the company a A-hole?

Which makes this question a bit of a suprise.
She's his wife so I'll let her answer this one, too.

Here is my experience with them.

very hard to work on yourself (people are talking about how easy the sport kiss is to work on ect)

There isn't all that much to work on, really, the only tool needed is a small screw driver to adjust setpoint and calibrate sensors. I find the Prism very maintainance friendly.

The only down side i have read about so far is that the Prism takes alot to get ready for a dive( a big check list) -- is this true?

Not true. As I stated in the beginning, the Prism is very transparent and user friendly. Pre-dive isn't any more complicated than other rigs, calibration and setpoint selection very easy (I like easy, and I rather screw than push buttons, can you tell? ).
The main difference is that you actually have a list on paper rather than handsets ''walking" you through it. If you have Bozanic's Mastering Rebreathers, the Pre- and Post Dives are in there.
As Andy pointed out, filling the radial scrubber might take a bit longer, but as the article stated, it last longer, too.

Im looking to use the Rb i end up with for all types of diving (from play dives to cave) Im just trying to do homework to find out the best overall rb that will work for just about any situation.

Personally, I believe the Prism is the best allround rebreather on the market right now. Bozanic here in CA and Tysall in FL are two instructors who use theirs in caves ... you're well located.

Stefan

 

[padiscubapro]

That means that the Prism scrubber can absorb 405 liters of CO2.
Joe's Inspiration can absorb 288 liters of CO2, the upcoming Evolution managed 192 liters to get its CE aproval. The Ouroboros should be able to absorb 240 litres of CO2, same for the SportKiss asuming its rating is based on CE protocol (which makes sense as Jetsam wants to pursue CE certification). I don't know what what sort of testing has been done on the Classic Kiss or the Meg. So even when you consider the difference in protocol the Prism beats the competition hands down.

Usually at this point someone throws the fact that the Prism has a larger cannister into the ring. Aside from the obvious 'So what, yours doesn't come with a larger scrubber' even if you go by liters-absorbed/pound-of-material the Prism comes out ahead by almost 20%, In other words it has a very efficient scrubber. Good basic engineering.

The only CCRs I'm aware of that has a longer duration based on available independent testing are the ones equiped with MK16 center sections, which absorb 454 liters CO2 (although they were tested to 1.0% CO2 loop content rather than CE and current NAVY limit of 0.5%).

Stefan

first a few points to clarify, testing at a higher flow rate will not only eat up chemical faster but it will also skew the results shorter because there will be a point were some co2 is being removed not just all of it (the dwell/contact time) is different, the higher rate will change the overal "scalling" slightly

as to how much co2 it can absorb - the prisms and inspirations were both tested using the same chemical (although now a different manufacture is recommended with the prism).. its manufacture rating is only 140 liters per kg, this means BY MANUFACTURER (chemical) ratings the prism if 100% effective it could remove 381 (individual batches could yield a higher adsorbtion rate (and frequently do, but we should respect guaranteed minimums), and the inspiration would be 350.. therefore the prism threoretically could do 4hrs at 1.6lpm, and the inspiration 3.6 hours @ 1.6, actual testing on machines has shown at worse case slightly above 3.25 hours, other runs closer to theoritical.. which is about a 90% efficiency (worse case) at 1.6lpm.. at a slower flow rate the efficiency should go up since there will be a longer contact time with the chemical, and in the design of an axial scrubber, the chemical gets exhaused in a linear fashion, so the flow rate near the break throug point is critical.

The only way we will really know how closely they compare is when the same test criteria are used., and eventually the prism will have to do testing to CE standards if they want to sell legally in europe.

The longest duration cannister at high work loads that I was aware of was the ut240 it was rated at 240m for a 1.8 lpm flow rate.. I dont remember how much checmical it used but it I would say it was more than 6 lbs

as for manufacturing numbers I do know what a very recent serial number was for the meg, a good idea on the jetsam numbers (from recent conversations), and a reasonable estimate on how many prisms are out there from various stuff I have seen posted, its not a significant number of units so even if I was 50% off, the actual comparison is still reasonable..

In conversatons I have had with a few sources I can't state, plus conversations I have had with Martin, I'd say the numbers are reasonable..

A few years ago when ap was not equipped for high demand they were making 10-15 units a week (lead time on units was about 6 months at the worse time), the demand has increased and on the classic units they are readily available (the vision is another story).. That tells me at worse case they can produce at least 100-200 units a month, but since they dont publish exact figures we can just speculate...

 

[nl_carey]

Just another point to make from someone who has done a bit of reading, and while it might seem like it, isn't biased towards any rebreather...

1. If you want eCCR, the PRISM, if you can get one, really seems to be pretty much the best choice around. Some people use a Classic KISS with a HammerHead, but the availability may become an issue in the future with the new DiveRite.
2. If you want backmounted lungs, the Classic or Sport KISS are pretty much the only options. The Ouroborous looks awesome, but still not available to the public?

Inspiration divers seem to like their unit, but in terms of overall design and customisation and flexibility, it doesn't stack up. A friend of mine has a titanium shell, and neoprene counterlungs he's planning on matching with the new Inspo electronics, which seems like a great combination - but why buy an RB to chuck away most of it? You have to give APV credit for really enabling RB technical diving to gain enough momentum to make the general public aware of it, at least.

I'm going a Sport KISS simply because it suits my specs - I just wanted a light, simple, well designed unit. The Classic KISS was an option, but there are many advantages in the Sport KISS with simplicity, maintenance, and streamlining. However, as Gordon and Kim say, it's not designed for technical diving. This isn't a problem for me at this time - I wanted a breather for the advantages of silence, warm air and gas extension, not simply to go deeper easier. Travel and price are a function of the design, and pretty much a bonus, but not critical in my mind. I had thought of conversions of the Azimuth or Dolphin, but decided that they were too complicated in the end to pursue.

However, I wouldn't think the Sport KISS is the unit to go caving. The Classic has a track record, but as yet there may be potential problems that mean you wouldn't want to be stuck in a cave with a Sport KISS. The width could be a problem in constrictions too. Issues like water trapping and breathing off the scrubber without any way to reduce heat levels (like water sapping heat out of an inhale counterlung) are two things that will need to be track-tested over the course of time.

I have looked at PRISM's, and they are great - but I ruled them out due to the fact they are eCCR, which I was slightly against for my first RB (personal reasons, and having to deal with a range of potential problems that the PRISM, admitted, generally solves), and they had front-mounted lungs. My experience with front-mounted lungs on an Inspiration left me feeling there was an organic thing on my chest, which was a profoundly unsettling feeling. That, and a slightly clunky backup PO2 guage, were the only two things I didn't like about the PRISM. A pretty small list.

If you're after a good technical RB that is suited for things like wrecks and caves, it's hard to beat the Megolodon (which a friend of mine dives and seems like a fantastically durable unit, and with potentially improved electronics with deco calcs in the near future) and PRISM. The PRISM seems to have a range of electrical safeguards the Meg doesn't, as well as an advantage of obtainability, at least in the medium term.