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Rebreather

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Rebreather

Post Number:#1  Postby najibest » Tue May 22, 2007 5:54 pm

it's been a while since i started a topic (lately SKK/BKK is the main topic starter heh :P ) so i'll start this topic. i was really interested seeing Snafu diving his rebreather at the pool last weekend. i did some research and found 3 main types of rebreathers:

1. oxygen rebreather

2. semi close circuit rebreather (SCR)

3. closed circuit rebreather (CCR)

and usually people would use the SCR and CCR for recreational/technical diving. i had a talk with Katakpink yesterday and he told me that CCR has lots of advantages over SCR. so i would assume that it's better off if (and only if.. too expensive maa) i want to go into rebreather, the best way to go would be straight to CCR. so the main thing that i want to ask in this forum would be what's the advantages (if there is any) of SCR compared to CCR other than the lower cost. also i would like to know more about mCCR and eCCR and the feasibility of diving these rebreathers in Malaysia. hopefully the sifus  here can share some info :)
najibest
 
Topic author

Re: Rebreather

Post Number:#2  Postby SeaDemon » Tue May 22, 2007 8:21 pm

O2 rebreather is mainly (or only) for military use. None was built for recreational use if I am correct. However, some older units have found their way to civilian experienced rebreather divers.

SCR is mainly for recreational diving...limited to 33m, especially in the Draeger units (Dolphins and Rays) as they have passive O2 addition injection orifice that are either 32% or 36%. There is a tendency of gas build-up in the breathing loop because other other breathing gas is added at a constant rate as O2 is, and this needs to be vented out from time to time to prevent over-expansion. And because of this, some good O2 gets vented out as well. And as gas is injected more and more, and ventilation takes place, your breathing gas lasts shorter as SCR maintains a constant fO2. The deeper you go, the lesser your time at bottom is, and the higher the chance for O2 Toxicity as PPO2 is not constant. Some even say, the most ideal depth for a SCR is at around 20m (coincidentally that is where most marine life dwell), where a dive can last quite long. At 30, your gas could last a lot lesser than of those using OC scuba.

CCR Image

CCRs inject breathing gas and O2 separately. CCRs maintain a more or less constant PO2 instead of fO2. The controller takes charge of this in eCCR and adds more O2 when the PO2 drops below the set point. So, a dive on a CCR, no matter how deep, the controller will maintain the same PO2. You can last hours and save gas using the CCR...your limitations would be physical, and that of the scrubber.

Without the controller, you will have to make do with your natural solenoid and processor (fingers and brain), and watch the PO2 meter.

Advantages of SCR over CCR other than price: easier and cheaper maintenance. Smaller in size.

Feasibility of using CCRs in Malaysia: good for deep wreck dives, cavern penetrations etc. However, blending facilities are still short to support this kind of diving.

Now,I pass the ball to rebreather owners. ::)
SeaDemon
 
Topic author

Re: Rebreather

Post Number:#3  Postby najibest » Wed May 23, 2007 12:32 pm

thanks dem for the clarification.. any other comments from rebreather users? heh :P
najibest
 
Topic author

Re: Rebreather

Post Number:#4  Postby GOD » Wed May 23, 2007 4:25 pm

Hmmmmmm... I will give my comment later ok.

I am a simple diver & I choose eCCR because ..... [highlight]TO BE CONTINUE[/highlight]
GOD
 
Topic author

Re: Rebreather

Post Number:#5  Postby nizaha » Wed May 23, 2007 9:12 pm

i just hate bubble  ;) , so noise underwater that way i choose CCR  ;)

Safe diving

Zaha
nizaha
 
Topic author

Re: Rebreather

Post Number:#6  Postby GOD » Thu May 24, 2007 1:29 am

Hi Najibest,

1st of all & the most important .... Rebreather is just a tool.

You need to list down all the dive requirement before looking into what tools to need.

Do sit down & give it a thought.... CCR if you plan to dive deep & using helium in the future, save gas & save money on gas.... complicated equipment if is Electronic control.

If for UW photography, I would suggest getting something like Drager Dolphin as this will give you some options for upgred in the future if you decided to change your diving.

Why would you be looking at rebreather at the 1st place?

;D
GOD
 
Topic author

Re: Rebreather

Post Number:#7  Postby nizaha » Thu May 24, 2007 3:32 am

HI Najibbest..

Snafu is right !
extra money involved . Diving with CCR is completely different world , you need to be consistent ! to be hornest i start consider myself to purchase CCR unit last year after i realized i spent  chunck of money on Helium with open circuit. and i do alots of diving here in cold water or back in tioman. Also  i spend couple of month asking people and friend to find a right unit for me. try out couple of unit.

I moving to rebreather because i start getting serious into deep diving ( trimix) and u/w photo. that's reason why i move to CCR and i love'it.

i hope this might solved your problem either you go to CCr or wait for awhile.

Safe diving

Zaha
nizaha
 
Topic author

Re: Rebreather

Post Number:#8  Postby najibest » Thu May 24, 2007 9:22 am

there're few reasons why i'm thinking about rebreathers. the main would be because it would extend ur bottom time due to the recirculation of gas (i'm a bit of a gas hog, i tank would last about 30 min, 40 min if i'm lucky) and from what i heard it would reduce/shorten deco stop (i guess mainly for CCR) - correct me if i'm wrong here

i don't think i would be going into technical diving or anything anytime soon but wreck diving is something that i really want to do. but considering the fact that i consume so much gas that i can only last about 30-40 minutes at about 20-25m, going twin tank with nitrox would be the other option to go should i want to extend my bottom time but twinset=more bulk :). thus why i'm considering the SCR, well drager dolphin to be exact as it should weigh about the same as a normal OC setup

UW photography is something that i want to do and going almost bubble-less with the SCR and completely bubble-less with the CCR would help a lot

but i guess in the end for me, cost would determine the path that i choose. i've been reading the rebreatherworld forum a bit and most people there would suggest going straight to CCR especially with the availability of the KISS ccr that cost only a bit more than the drager dolphin (overseas most probably, i have no idea how much as KISS ccr cost here). but then again i have to look into the feasibility of using the unit in Malaysia, is it easy to maintain? easy to travel with? easy to service? etc.. how about customer support and spare parts for the CCR? and is using a CCR significantly more expensive than a normal OC setup per dive trip?

so the bottom end would be, i'm interested in rebreather to extend my bottom time and help me take better UW pictures without disturbing marine life :) and the main reason i'm interested in SCR would be because it doesn't cost that much compared to a high end OC setup and is great for recreational diving but i also don't know how much a CCR (i heard KISS is affordable) cost here heh :)

hopefully u guys can give me more input on whether to go rebreather or not while i try to save money heh :P
Last edited by najiBEST on Thu May 24, 2007 10:19 am, edited 1 time in total.
najibest
 
Topic author

Re: Rebreather

Post Number:#9  Postby SeaDemon » Thu May 24, 2007 11:18 am

If you don't plan to go deep, and don't plan to go tech, Draeger Dolphin would be good for you, for the simplicity in operating and maintaining the unit. A second hand unit should cost no more than RM6K ready to fly. To get a CCR just because you want to do recreational dives is a bit of an overkill.

The notion that a bubble-less unit gives you better advantage because you can get a lot closer to the marine life, to me is a myth. The animal is not stupid...if it sees something bigger than itself coming its way, the most natural thing for it to do is to get the hell out of there. You may get in slightly closer because with no bubbles, there is less vibration caused in the water (less noise).

But for me, going SCR and/or CCR means I have greater stability in terms of buoyancy when doing UW Photography or Videography. No ups and downs.

And since you're on Nitrox when doing the SCR/CCR, yes, your NDL is longer or your SIT is shorter.

Go for the Draeger Dolphin. It is a PADI Specialty by itself.

The downside of SCR/CCR diving in Malaysia is, not many DCs offer facilities to support this kind of diving.
Last edited by SeaDemon on Thu May 24, 2007 11:20 am, edited 1 time in total.
SeaDemon
 
Topic author

Re: Rebreather

Post Number:#10  Postby HoleMaster » Thu May 24, 2007 2:05 pm

If you don't plan to go deep, and don't plan to go tech, Draeger Dolphin would be good for you, for the simplicity in operating and maintaining the unit. A second hand unit should cost no more than RM6K ready to fly. To get a CCR just because you want to do recreational dives is a bit of an overkill.

The notion that a bubble-less unit gives you better advantage because you can get a lot closer to the marine life, to me is a myth. The animal is not stupid...if it sees something bigger than itself coming its way, the most natural thing for it to do is to get the hell out of there. You may get in slightly closer because with no bubbles, there is less vibration caused in the water (less noise).

But for me, going SCR and/or CCR means I have greater stability in terms of buoyancy when doing UW Photography or Videography. No ups and downs.

And since you're on Nitrox when doing the SCR/CCR, yes, your NDL is longer or your SIT is shorter.

Go for the Draeger Dolphin. It is a PADI Specialty by itself.

The downside of SCR/CCR diving in Malaysia is, not many DCs offer facilities to support this kind of diving.


Which dive centre in Malaysia provides Drager Dolphin certification?
HoleMaster
 
Topic author

Re: Rebreather

Post Number:#11  Postby najibest » Thu May 24, 2007 2:20 pm


Which dive centre in Malaysia provides Drager Dolphin certification?


i think rec and tec do offer drager dolphin certification :)
najibest
 
Topic author

Re: Rebreather

Post Number:#12  Postby nazimkecik » Thu May 24, 2007 2:31 pm

DiveAsia Tioman Salang got course on drager dolphin rebreather. You might even be able to purchase a 2nd hand set from them after the course or work out a package. I did inquire about this one time. The person to get in touch with is Roger Ng at diveasia1@hotmail.com or diveasia@tm.net.my . They are dreager rebreather friendly dive center, provide support, parts and service too. Good Luck!
Last edited by nazimkecik on Thu May 24, 2007 2:34 pm, edited 1 time in total.
nazimkecik
 
Topic author

Re: Rebreather

Post Number:#13  Postby nizaha » Thu May 24, 2007 9:10 pm

Hi Najibbest..

I completely agree with your point. Extremely important  go find the good instructor .Ask Snafu who his recomended in Malaysia.  If you look at RB world, they sell Doplhin for $1200 US with extra stuff aswell. really worth it ! you might consider to get the unit before start your course. at least you can start setup your configuration. Kiss rebreather by jetsam very popular and easy to travel with.. they coming with Sport and classic version which is sport slight small. ( $ US$5,600 for classic andf $5,200 for sport) brand new. really good feedback rating for rebreather user..i know few friend around toronto happy with their unit so far.

Safe diving and have fun with your unit  8-)

Zaha
nizaha
 
Topic author

Re: Rebreather

Post Number:#14  Postby najibest » Sun May 27, 2007 5:36 pm

Hi Najibbest..

I completely agree with your point. Extremely important  go find the good instructor .Ask Snafu who his recomended in Malaysia.  If you look at RB world, they sell Doplhin for $1200 US with extra stuff aswell. really worth it ! you might consider to get the unit before start your course. at least you can start setup your configuration. Kiss rebreather by jetsam very popular and easy to travel with.. they coming with Sport and classic version which is sport slight small. ( $ US$5,600 for classic andf $5,200 for sport) brand new. really good feedback rating for rebreather user..i know few friend around toronto happy with their unit so far.

Safe diving and have fun with your unit  8-)

Zaha


seems like there're people on this forum interested in rebreathers. cost seems to be the main obstacle to go CCR but i guess SCR is definitely within reach (well used SCR at least). since i don't think other SCR (the OMG azimuth or other SCR - correct me if i'm wrong) has made it to Malaysia i guess the most widely available scr over here would be the Drager Dolphin

i'm sold to the idea of having a dolphin but i'm still quite skeptical on the mobility of the unit. i guess it's not a good idea to have the dolphin as the main diving instrument (should still keep an OC set :P). the question now is how many dive centers here in Malaysia can cater the need of a rebreather diver. i was told that to run the dolphin u only need to find a DC that support nitrox. but how many actually support nitrox around here? i know for sure a few on tioman do support nitrox, but how about redang and perhentian? and can i use their tank or do i need to bring my own tank for use with the dolphin? i read in RB world that some people even use AL50 on the dolphin but if i'm not mistaken the normal tank provided is the AL80 or steel 80 - correct me if i'm wrong here and if i'm not mistaken the dolphin uses a different kind of valve

but aside from these problems, i still do see the dolphin as a viable alternative to OC set. i've been reading around and found out that the scrubber can be used up to 3 hrs/fill and with the correct tank size and around 20-25m diving depth, 1 nitrox fill should be enough for 3hrs meaning u only need to replace the scrubber and nitrox fill once a day - pretty convenient i would say

anyway i would say i would still need more input before i can decide whether to get a rebreather or not as mobility and nitrox/dolphin friendly DC would be the main concern. a tryout on a rebreather would also help heh :) so that i can know the additional pre dive preparation needed with a rebreather

keep the info coming u guys :)
Last edited by najiBEST on Sun May 27, 2007 5:37 pm, edited 1 time in total.
najibest
 
Topic author

Re: Rebreather

Post Number:#15  Postby bobo » Sun May 27, 2007 6:01 pm

1st it was interesting, after a while, i get confused with najib asking.. hehehe mebbi, Snafu n Zaha can clarify on this, but I would interested in Inspiration.. like Zaha said on the other thread, buy on ebay would be risking all the way unless, u know the individually personally...

like this on ebay.. http://cgi.ebay.com/DRAGER-RAY-Underwat ... dZViewItem
DRAGER RAY Underwater Rebreather Scuba Dive Vest NR USD$600++

Anyway, Jib, dont make things pening lalat...

try this one hehehe...

Rebreathers in general
A rebreather is circulation system for your breathing gas, in theory a rather simple system that allows you to use the part of the oxygen that is left in the respiratory gas mix, after you have exhaled it from your lungs.

In simple terms the exhaled air will take a trip around the loop of the rebreather and is used again. Before you breathe the gas mix again, it will travel through a filter that cleans out the carbon dioxide.

Then there is the question of oxygen? Every time the gas mix passes your lungs a small part of the oxygen is metabolised by your body. A normal person will metabolise approximately 1 litre oxygen per minute.

It’s crucial that the system is replenished with fresh oxygen in just the right amount. Both too little and to much can be fatal.

The mechanism to compensate for the use of oxygen marks the most important difference between semi-closed and fully closed rebreathers. The semi-closed units will inject some sort of nitrox into the loop at a constant pace, and to keep the volume constant it will compensate by releasing some bubbles.

However, most fully closed rebreathers will measure the actual amount of oxygen in the loop, and replenish just the right amount in accordance with the metabolism. This is why there are no bubbles from a fully closed system.

more here http://www.jj-technique.com/Rebreather_ ... g_main.htm
bobo
 
Topic author

Re: Rebreather

Post Number:#16  Postby najibest » Sun May 27, 2007 6:12 pm

heh  :P
najibest
 
Topic author

Re: Rebreather

Post Number:#17  Postby nizaha » Sun May 27, 2007 11:15 pm

Hey guy..

www.silentdiving.com

they tell you everything what you need for Buddy inspiration rebreather.price and etc..

How bout we wait Snafu come back from tioman, see what he can add about this conclusion, I think he know better then me how to get stuff especially in Malaysia !

Safe diving..
Zaha
nizaha
 
Topic author

Re: Rebreather

Post Number:#18  Postby najibest » Sun May 27, 2007 11:48 pm

Hey guy..

www.silentdiving.com

they tell you everything what you need for Buddy inspiration rebreather.price and etc..

How bout we wait Snafu come back from tioman, see what he can add about this conclusion, I think he know better then me how to get stuff especially in Malaysia !

Safe diving..
Zaha


heh... me always looking for good stuff :P ...let's wait for snafu to add some comments :)
najibest
 
Topic author

Re: Rebreather

Post Number:#19  Postby SeaDemon » Mon May 28, 2007 3:00 am

Najib, it can be a hassle to try and make rebreathers mobile...SCR and CCRs alike. That is why Snafu and Nizaha have OC sets to use (regs and stuff). And using rebreathers, especially the CCR, means having near-perfect buoyancy. It is not forgiving for the complacent. It is not forgiving for those who never bother to check their gauges.

Do more dives, practise, practise and practise. And even if you go for either the SCR or CCR, practise, practise, practise in the pool before you actually fly it in the open seas.
SeaDemon
 
Topic author

Re: Rebreather

Post Number:#20  Postby wing0112 » Mon May 28, 2007 1:33 pm

is it really diff ar for SCR n CCR user with normal old school reg... how does it affect ur buoyancy?
wing0112
 
Topic author

Re: Rebreather

Post Number:#21  Postby SeaDemon » Mon May 28, 2007 3:47 pm

is it really diff ar for SCR n CCR user with normal old school reg... how does it affect ur buoyancy?


You inhale, it doesn't make your buoyancy positive; you enhale also it doesn't make you negative. You're breathing in your own breath!
SeaDemon
 
Topic author

Re: Rebreather

Post Number:#22  Postby pink-fins » Mon May 28, 2007 3:51 pm

is it really diff ar for SCR n CCR user with normal old school reg... how does it affect ur buoyancy?


You inhale, it doesn't make your buoyancy positive; you enhale also it doesn't make you negative. You're breathing in your own breath!


Eigh!!! Smelly!!! Snafu brush teeth or not?  ::) ::) ;D
pink-fins
 
Topic author

Re: Rebreather

Post Number:#23  Postby GOD » Mon May 28, 2007 4:23 pm

Eigh!!! Smelly!!! Snafu brush teeth or not?  ::) ::) ;D


Eh I use Colgate & Listerin & errrrrr.... and....etc.

Ask JIM ... he use my rebreather after me.

;D
GOD
 
Topic author

Re: Rebreather

Post Number:#24  Postby pink-fins » Mon May 28, 2007 4:30 pm

Eigh!!! Smelly!!! Snafu brush teeth or not?  ::) ::) ;D


Eh I use Colgate & Listerin & errrrrr.... and....etc.

Ask JIM ... he use my rebreather after me.

;D


Jim practically kissed smoochy smoochy you!!  ;) ::)
pink-fins
 
Topic author

Re: Rebreather

Post Number:#25  Postby nizaha » Mon May 28, 2007 8:18 pm

ehhehe.. my in law is dentist,, who need toothbrush and tooth paste let me know.. !!! lots in stock !! :D :D

OK guy i'm  gone for diving..talk to you'll soon..

Zaha
nizaha
 
Topic author

Re: Rebreather

Post Number:#26  Postby bobo » Mon May 28, 2007 9:31 pm

Snafu if homebrew rebreather ok or not, cost wise..???
bobo
 
Topic author

Re: Rebreather

Post Number:#27  Postby GOD » Mon May 28, 2007 10:55 pm

Snafu if homebrew rebreather ok or not, cost wise..???


Homemade .... can be done & of course is cheaper.

Who is going to test dive it? You are better to buy Ex-Navy set-up .... rebuild it & dive it.

Anyway SCR are cheap nowdays ... get 2nd hand & use it la.

;D
Last edited by GOD on Tue May 29, 2007 12:00 am, edited 1 time in total.
GOD
 
Topic author

Re: Rebreather

Post Number:#28  Postby bobo » Mon May 28, 2007 11:45 pm

hehehe SCR... can upgarde with same unit to CCr or not..???
bobo
 
Topic author

Re: Rebreather

Post Number:#29  Postby GOD » Tue May 29, 2007 12:01 am

hehehe SCR... can upgarde with same unit to CCr or not..???


It can be done & is not cheap.

;D
GOD
 
Topic author

Re: Rebreather

Post Number:#30  Postby bobo » Tue May 29, 2007 12:10 am

not cheap cheaper than second hand CCR or not cheap expensive than second hand CCR...  ;)...

eager already.. by the way snafu, what is the cost for the training..
bobo
 
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