Lets not forget the "cool techie" factor. Some just like diving something different.
Why Rebreathers?
- Thread starter Shawley
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SFLDiver3445
Contributor
Sphawley,
You've gotten some good answers so far, but essentially, a rebreather is leaps and bounds more efficient than open circuit scuba! With a rebreather, you can usually decrease the amount of gas you need to carry, increase your bottom time and minimize your decompression obligation for any given dive. A rebreather will also allow you to either eliminate of minimize the bubbles you exhale while diving, which will allow you to be quieter underwater and generally get closer to marine life without spooking them.
The efficiency that is gained from the use of a rebreather really becomes evident the deeper and/or longer you dive, becuase that's where the amount of gas you would use on open circuit, as compared to a rebreather for the same dive, really becomes evident. Furthermore, a rebreather's efficiency also becomes evident when doing multiple dives (example, I can typically do 4 one-hour long dives with my rebreather without having to change tanks or scrubber material).
There are other advantages, but that's a good summary; however, everything in life has disadvanages that come with the advantages, and a rebreather is certainly no exception to that rule:
Unfortunately, the current design of rebreathers is exponentially more expensive to purchase than open circuit equipment. Current rebreathers also require a significant more amount of time and focus on assembly and dissassembly of the unit. Most modern design rebreathers have some excellent back-up safety features that should aid to get you out of a bind if the unit has some types of malfunction, but those features entail double and triple redundancies, which creates more items to double and triple check, as well as creating more potential failure points that could make the dive be canceled. Because of the potential for something to to go wrong and make you have to stop using the rebreather an any point in time, most divers carry off-board open circuit bail-out (small tanks under their arms to breathe in case of a failure). Since divers may be doing deep and/or long dives, they always need to carry enough gas to allow them to complete any required decompression and make it back to the surface, so the tanks can add up on deeper dives.
Because of the complex nature of current design rebreathers, training is another essential part of using a rebreather. Even if you are a very experienced diver, you usually still need to complete approximately a one week-long course to get certified for your first use on the particular rebreather you purchased; infact, the manufacturer will usually not even give you the codes to unlock the rebreather's computer, unless you are certified or are enrolled in a course, and even then they will generally only provide the codes to your instructor.
In summary, rebreathers are great, but that is the subject of great debate, because many people do not feel the advantages out-weigh the disadvantages. I've been using mine for about six months and love it, but many people feel the $ and time I dedicate to it is foolish - opinions vary!
Footnote: Everyday, more and more manufacturers are coming out with new designs. It appears that the near future has in store some new designs that will make the average recreational user more apt to consider one, becuase they are seriously focussing on simplifying the number of components that need to be dealt with to dive it recreationally. If they solve that puzzle and get the cost down to a more reasonable price point, there is not doubt rebreathers will eventiall become more mainstream, because there is no doubt as the the efficiencies gained from using one.
Please keep in mind, this is just the humble opinion of a diver that has been diving for over 20 years and has now been diving a rebreather for 6 months and loves it!
You've gotten some good answers so far, but essentially, a rebreather is leaps and bounds more efficient than open circuit scuba! With a rebreather, you can usually decrease the amount of gas you need to carry, increase your bottom time and minimize your decompression obligation for any given dive. A rebreather will also allow you to either eliminate of minimize the bubbles you exhale while diving, which will allow you to be quieter underwater and generally get closer to marine life without spooking them.
The efficiency that is gained from the use of a rebreather really becomes evident the deeper and/or longer you dive, becuase that's where the amount of gas you would use on open circuit, as compared to a rebreather for the same dive, really becomes evident. Furthermore, a rebreather's efficiency also becomes evident when doing multiple dives (example, I can typically do 4 one-hour long dives with my rebreather without having to change tanks or scrubber material).
There are other advantages, but that's a good summary; however, everything in life has disadvanages that come with the advantages, and a rebreather is certainly no exception to that rule:
Unfortunately, the current design of rebreathers is exponentially more expensive to purchase than open circuit equipment. Current rebreathers also require a significant more amount of time and focus on assembly and dissassembly of the unit. Most modern design rebreathers have some excellent back-up safety features that should aid to get you out of a bind if the unit has some types of malfunction, but those features entail double and triple redundancies, which creates more items to double and triple check, as well as creating more potential failure points that could make the dive be canceled. Because of the potential for something to to go wrong and make you have to stop using the rebreather an any point in time, most divers carry off-board open circuit bail-out (small tanks under their arms to breathe in case of a failure). Since divers may be doing deep and/or long dives, they always need to carry enough gas to allow them to complete any required decompression and make it back to the surface, so the tanks can add up on deeper dives.
Because of the complex nature of current design rebreathers, training is another essential part of using a rebreather. Even if you are a very experienced diver, you usually still need to complete approximately a one week-long course to get certified for your first use on the particular rebreather you purchased; infact, the manufacturer will usually not even give you the codes to unlock the rebreather's computer, unless you are certified or are enrolled in a course, and even then they will generally only provide the codes to your instructor.
In summary, rebreathers are great, but that is the subject of great debate, because many people do not feel the advantages out-weigh the disadvantages. I've been using mine for about six months and love it, but many people feel the $ and time I dedicate to it is foolish - opinions vary!
Footnote: Everyday, more and more manufacturers are coming out with new designs. It appears that the near future has in store some new designs that will make the average recreational user more apt to consider one, becuase they are seriously focussing on simplifying the number of components that need to be dealt with to dive it recreationally. If they solve that puzzle and get the cost down to a more reasonable price point, there is not doubt rebreathers will eventiall become more mainstream, because there is no doubt as the the efficiencies gained from using one.
Please keep in mind, this is just the humble opinion of a diver that has been diving for over 20 years and has now been diving a rebreather for 6 months and loves it!
When I look at the disadvantages of rebreathing diving I think about:
1) Risk
2) Cost
3) Maintenance
#1 Risk - death! Recent news stories: death by tiger, plane accident, car runs into home killing someone watching TV, struck by lightning, stray bullet, I could go on and on. Remedies: Don't go to the zoo, dont fly, put up concrete barriers around your home, dont go outside when a storm is within 50 miles, wear bullet proof armor and head gear.
Most of us have been to the zoo, been in a plane, don't have concrete barriers around out home, go outside when its lightning, and dont wear bullet proof armor.
With the proper mindset and training CCR diving I would say is just slightly more risky than OC. I won't say equally as because yes, there is more to go wrong and well it requires good judgement. The latter can be influenced by alot of human factors. I am not aware of one CCR fatality that was caused by properly setup/dived equipment within its limits. They do fail, but this should not cause death.
#2 Cost - Expensive is a relative term. For some it's a signifcant investment, for others its not. CCR's with training range anywhere from 6k - 13k..and that figure is based on the most popular/available commercial models as of today. The cost per dive is not that much more than OC, but when using Trimix you are actually saving money in the long term.
#3 Maintenance - Yes, rebreathers require more maintenance. It may take around 15-20 minutes to setup, test, etc your gear. Then there is disinfecting, rinsing at the end of a days diving, etc. Again this is all relative. To me this is not a disadvantage at all, it is just something you absolutely have to do in order to dive a rebreather. It should almost be enjoyable, a sign of confidence that your unit is ready to dive or is ready for the next days diving.
For others it's a burden. Strapping on a BC, hooking up a reg, and making sure the air is on and not much more than that is all some want to do or are willing to do to go diving.
Risk - is diving a CCR worth the little added risk?
Cost - is diving a CCR worth the cost?
Maintenance - is diving a CCR worth the extra care needed?
J
1) Risk
2) Cost
3) Maintenance
#1 Risk - death! Recent news stories: death by tiger, plane accident, car runs into home killing someone watching TV, struck by lightning, stray bullet, I could go on and on. Remedies: Don't go to the zoo, dont fly, put up concrete barriers around your home, dont go outside when a storm is within 50 miles, wear bullet proof armor and head gear.
Most of us have been to the zoo, been in a plane, don't have concrete barriers around out home, go outside when its lightning, and dont wear bullet proof armor.
With the proper mindset and training CCR diving I would say is just slightly more risky than OC. I won't say equally as because yes, there is more to go wrong and well it requires good judgement. The latter can be influenced by alot of human factors. I am not aware of one CCR fatality that was caused by properly setup/dived equipment within its limits. They do fail, but this should not cause death.
#2 Cost - Expensive is a relative term. For some it's a signifcant investment, for others its not. CCR's with training range anywhere from 6k - 13k..and that figure is based on the most popular/available commercial models as of today. The cost per dive is not that much more than OC, but when using Trimix you are actually saving money in the long term.
#3 Maintenance - Yes, rebreathers require more maintenance. It may take around 15-20 minutes to setup, test, etc your gear. Then there is disinfecting, rinsing at the end of a days diving, etc. Again this is all relative. To me this is not a disadvantage at all, it is just something you absolutely have to do in order to dive a rebreather. It should almost be enjoyable, a sign of confidence that your unit is ready to dive or is ready for the next days diving.
For others it's a burden. Strapping on a BC, hooking up a reg, and making sure the air is on and not much more than that is all some want to do or are willing to do to go diving.
Risk - is diving a CCR worth the little added risk?
Cost - is diving a CCR worth the cost?
Maintenance - is diving a CCR worth the extra care needed?
J
mrfixitchapman
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...and the dive boat leaves in an hour. If you dive regular charter trips open circuit will be all you need. Go technical and rebreathers begin to look good. You will, however, be striding into the deep end of the responsibility pool. Be ready. Know what you are doing. Know what you are capable of doing.
DC
DC
The thing that frightens me, when you are talking about risk, is that hypoxia has few symptoms, and the ones it does have aren't likely to make you recognize what's happening to you. Unlike CO2 buildup, which causes anxiety and shortness of breath, hypoxia causes euphoria and then unconsciousness. I like the fact that, on open circuit, I know what I put in my tanks is what I am breathing, through the whole dive. But then, the longest dive I'm likely to do won't be more than 90 minutes, and that only in warm water.
Caves may make me rethink things, eventually, but cave diving isn't the kind of recreational diving most people are doing.
Caves may make me rethink things, eventually, but cave diving isn't the kind of recreational diving most people are doing.
H2Andy
Contributor
the problem is that rebreathers are (no matter how much people try to downplay this) on a different complexity level than the demand valve used in scuba
with scuba you breathe in and out and the equipment does the rest; if it malfunctions, you know it (either no air or freeflow)
with rebreathers, there are quite a few things you need to do right, and keep an eye on, that if you screw up or they go wrong (and people screw up and thinsg go wrong) will kill you while you're breathing in and out without a care in the world
almitywife
Vegemite Mod
Lynne... my hubby has the MEG with a HUD and ive noticed im starting to watch the blinking lights now for the PO2 readings
If you are the kind of person that just wants to go along without having to think about your gear while on a leisurely dive, and you know that you are not the type to pay attention, then a rebreather is not for you. If you are the type that is diligent and pays attention to what is going on during the dive, then a rebreather can actually be safer than open circuit diving.
A rebreather buys a tremendous amount of time for the diver when things do go wrong. For instance, if you are way back in a cave and you experience a complete silt out and become separated from the line (which is a no-no in itself), you can park, wait an hour for the silt to clear, search for the line, and take your time getting out without missing any decompression obligation. If you get lost inside a wreck or entangle, you can take as long as you need to get yourself out of the situation. You have more than enough breathing gas to last for hours no matter what the depth. This is huge!
Even if a component fails, there are still many options for the rebreather diver that are not available for the open circuit diver. For example, if your unit starts having the CCR equivalent of a free flow, shooting gas into the unit, you can shut that portion of the unit down and fly the unit using an alternative that gives you just as much time as if your unit were working 100 percent. If a problem occurs, there can be several alternatives to the rebreather diver rather than just "it works or it doesn't." You learn about all of these methods in your training.
For some diving, a rebreather makes life much easier. If you want to see a dive that is a perfect example, just download this link. (Just so you know, it is HD video, and it will take a long time to download, maybe 45 minutes depending on connection speed. However, I assure you that you will enjoy the footage.) If we had done this dive on open circuit, we would have had to make two dives instead of one, dropping lots of open circuit tanks along the way to make sure we would have enough gas to get to our destination and back. The actual dive was about three hours 15 minutes, and the average depth was about 120 feet.
A rebreather buys a tremendous amount of time for the diver when things do go wrong. For instance, if you are way back in a cave and you experience a complete silt out and become separated from the line (which is a no-no in itself), you can park, wait an hour for the silt to clear, search for the line, and take your time getting out without missing any decompression obligation. If you get lost inside a wreck or entangle, you can take as long as you need to get yourself out of the situation. You have more than enough breathing gas to last for hours no matter what the depth. This is huge!
Even if a component fails, there are still many options for the rebreather diver that are not available for the open circuit diver. For example, if your unit starts having the CCR equivalent of a free flow, shooting gas into the unit, you can shut that portion of the unit down and fly the unit using an alternative that gives you just as much time as if your unit were working 100 percent. If a problem occurs, there can be several alternatives to the rebreather diver rather than just "it works or it doesn't." You learn about all of these methods in your training.
For some diving, a rebreather makes life much easier. If you want to see a dive that is a perfect example, just download this link. (Just so you know, it is HD video, and it will take a long time to download, maybe 45 minutes depending on connection speed. However, I assure you that you will enjoy the footage.) If we had done this dive on open circuit, we would have had to make two dives instead of one, dropping lots of open circuit tanks along the way to make sure we would have enough gas to get to our destination and back. The actual dive was about three hours 15 minutes, and the average depth was about 120 feet.
H2Andy
Contributor
we're not talking about the external benefits of the respective units (i.e. no one will disagree that you get more time to solve emergencies using a rebreather)
and no one disagrees about the advantages of the rebreather in a variety of dive scenarios
but you are ignoring the complexity of the rebreather, and how many more things can go wrong with one than can kill you which are not an issue with scuba at all
even a superbly trained, on-the-ball diver will have less to manage, less to go wrong, and less chances to get into a life-threatening situation with scuba than with a rebreather. bottom line.
(you're basically trying to argue that for a good rider, a motorcycle is no more dangerous than a bicycle ... i just can't buy that argument)
and no one disagrees about the advantages of the rebreather in a variety of dive scenarios
but you are ignoring the complexity of the rebreather, and how many more things can go wrong with one than can kill you which are not an issue with scuba at all
even a superbly trained, on-the-ball diver will have less to manage, less to go wrong, and less chances to get into a life-threatening situation with scuba than with a rebreather. bottom line.
(you're basically trying to argue that for a good rider, a motorcycle is no more dangerous than a bicycle ... i just can't buy that argument)
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