I read so much about how good and safe it is to have a BOV that I think sometimes its used as a crutch.
This is MY opinion and I know that opinions are like arse holes, everyone has one! However I think that more and more people are fitting these to their units and expecting to be so safe because of them.
What has prompted me to write this is this thread
http://www.yorkshire-divers.com/foru...ebreather.html
I have the utmost respect for Howard for posting that. Be honest with yourself if it had been you would you have posted?
Howard made an error and it's an error that I'm sure he will never make again. All education has an associated cost I've always found that it's better to learn from others mistakes and reading that post will ensure that I always double check the "O"ring, spacer and scrubber.
I have had a few units with BOVs fitted and although I think that a BOV is useful It's not the be all and end all that some would have you believe. I prefer to get off the loop. Now having a BOV gives me a couple of breaths while I get off the loop and on to my bail out but even on units without a BOV I've got a bungeed reg around my neck that I can get onto quite quick if I need to.
If you're using a BOV it's unlikely that you'll have enough gas to surface so if you plan to use off board then you need this plumbing in from the start or a quick connect system. This in itself can cause problems. If you've bailed out then you have to change and plug in off board pretty sharpish and you may not be in a state where this is possible. If you run off board from the start then you can say that you should have sufficient to at least get you to a state where you've got yourself comfortable enough to be back in full control.
Once the shit has hit the fan regaining full control isn't easy underwater and one thing that I learned from the HSE/Shy video is that whoever is leading the dive, if they have any problem then they are no longer leader as they will be to concerned with themselves so someone has to take over and get everyone out of the water. This is decided before the dive and everyone is aware in the briefing.
If I need to bail out then weather a BOV is fitted or not I'll get onto open circuit as soon as possible. If I'm on OC then I have much more control. I can swap stages with other divers if I need more gas. If I'm deep diving I can make effective gas switches and everyone knows what I'm breathing from the reg in my mouth. If I'm on a Hypoxic dil/bailout then faffing with a gas connect is the last thing I want to do to switch gas (this is quite easy on the Sentinel as it's designed for off board but this is the exception not the rule) but I still want to be fully open circuit on a reg and not a BOV.
Bailing out to me means get to the surface as soon as possible but stay in control. now some CCRs have a system that allows you to dump manually like the Meg and Inspiration where you can pull or push a dump on the lungs but if you're heading for the surface trying to maintain control on assent it will be a task. Have you turned off your O2? is it injecting/flowing as the PPO2` drops on assent? Can you dump the lungs quickly and keep control of buoyancy? If your diving a unit with back mounted counter lungs you are relying on auto dumps and their settings. I have a habit of exhausting through my mouth and nose and not letting the auto dump do it's stuff as I feel more in control but when i'm off the loop I can't dump through my noise and mouth. My training on units with back mounted lungs is to open the loop and let the gas expel as I ascend. This couldn't work if I was breathing off a BOV. It does work however if you just let the loop go it floats above your head, even the heavy loop of the Sentinel so holding it with the loop open will expel gas on ascent and keep you in control.
A BOV is a nice addition but it's something else, like an ADV was something else. CCRs are becoming more complex and doing much more for the diver. The diver will be reliant on the unit and it's tricks if they don't understand and practice the basic principles of CCR diving. The Apocalypse and the Poseidon are designed to simplify CCR and make it easier but I have real concerns that too much reliance is being placed on the unit and that's because we the divers are not to be trusted. If you dive a basic rebreather and understand the basics and the principles. Learn skills and practice them then I'm sure if you're disciplined and you set basic rules and stick to them then you will be safe and be able to get yourself out of the poo.
I have never had to bail out where my life would be in danger if I didn't bail out. I try never to push the life of the scrubber. I change batteries when they're a bit down and cells at the first sign of weakness. I like to have full cylinders and more than enough bailout. I never rush to get into the water and will can a dive if I have any doubts.
I practice often and I never rely on my unit, I always have a bailout plan. I think that CCR divers should be able to dive without ADV, BOV, HUD and computer. You should always know your PPo2 and you should understand it.
I buy and sell quite a few rebreathers and it saddens me when someone is selling because they aren't that sure of the unit, some people take longer to get to grips with it than others but good skills and understanding will never be replaced with anything that can be manufactured. You can have the most tricked out CCR in the world but if you can't hold it together when the going gets tough then it's never going to be a happy ending.
I hate reading about the loss of a diver. I don't like reading about any indecent but if that makes diving that bit safer for me and if I can learn from it then I will and I'll try and pass it on.
Nobody wants to have these incidents and we all have an opinion, this is my opinion nothing more.
Dive safe.
This is MY opinion and I know that opinions are like arse holes, everyone has one! However I think that more and more people are fitting these to their units and expecting to be so safe because of them.
What has prompted me to write this is this thread
http://www.yorkshire-divers.com/foru...ebreather.html
I have the utmost respect for Howard for posting that. Be honest with yourself if it had been you would you have posted?
Howard made an error and it's an error that I'm sure he will never make again. All education has an associated cost I've always found that it's better to learn from others mistakes and reading that post will ensure that I always double check the "O"ring, spacer and scrubber.
I have had a few units with BOVs fitted and although I think that a BOV is useful It's not the be all and end all that some would have you believe. I prefer to get off the loop. Now having a BOV gives me a couple of breaths while I get off the loop and on to my bail out but even on units without a BOV I've got a bungeed reg around my neck that I can get onto quite quick if I need to.
If you're using a BOV it's unlikely that you'll have enough gas to surface so if you plan to use off board then you need this plumbing in from the start or a quick connect system. This in itself can cause problems. If you've bailed out then you have to change and plug in off board pretty sharpish and you may not be in a state where this is possible. If you run off board from the start then you can say that you should have sufficient to at least get you to a state where you've got yourself comfortable enough to be back in full control.
Once the shit has hit the fan regaining full control isn't easy underwater and one thing that I learned from the HSE/Shy video is that whoever is leading the dive, if they have any problem then they are no longer leader as they will be to concerned with themselves so someone has to take over and get everyone out of the water. This is decided before the dive and everyone is aware in the briefing.
If I need to bail out then weather a BOV is fitted or not I'll get onto open circuit as soon as possible. If I'm on OC then I have much more control. I can swap stages with other divers if I need more gas. If I'm deep diving I can make effective gas switches and everyone knows what I'm breathing from the reg in my mouth. If I'm on a Hypoxic dil/bailout then faffing with a gas connect is the last thing I want to do to switch gas (this is quite easy on the Sentinel as it's designed for off board but this is the exception not the rule) but I still want to be fully open circuit on a reg and not a BOV.
Bailing out to me means get to the surface as soon as possible but stay in control. now some CCRs have a system that allows you to dump manually like the Meg and Inspiration where you can pull or push a dump on the lungs but if you're heading for the surface trying to maintain control on assent it will be a task. Have you turned off your O2? is it injecting/flowing as the PPO2` drops on assent? Can you dump the lungs quickly and keep control of buoyancy? If your diving a unit with back mounted counter lungs you are relying on auto dumps and their settings. I have a habit of exhausting through my mouth and nose and not letting the auto dump do it's stuff as I feel more in control but when i'm off the loop I can't dump through my noise and mouth. My training on units with back mounted lungs is to open the loop and let the gas expel as I ascend. This couldn't work if I was breathing off a BOV. It does work however if you just let the loop go it floats above your head, even the heavy loop of the Sentinel so holding it with the loop open will expel gas on ascent and keep you in control.
A BOV is a nice addition but it's something else, like an ADV was something else. CCRs are becoming more complex and doing much more for the diver. The diver will be reliant on the unit and it's tricks if they don't understand and practice the basic principles of CCR diving. The Apocalypse and the Poseidon are designed to simplify CCR and make it easier but I have real concerns that too much reliance is being placed on the unit and that's because we the divers are not to be trusted. If you dive a basic rebreather and understand the basics and the principles. Learn skills and practice them then I'm sure if you're disciplined and you set basic rules and stick to them then you will be safe and be able to get yourself out of the poo.
I have never had to bail out where my life would be in danger if I didn't bail out. I try never to push the life of the scrubber. I change batteries when they're a bit down and cells at the first sign of weakness. I like to have full cylinders and more than enough bailout. I never rush to get into the water and will can a dive if I have any doubts.
I practice often and I never rely on my unit, I always have a bailout plan. I think that CCR divers should be able to dive without ADV, BOV, HUD and computer. You should always know your PPo2 and you should understand it.
I buy and sell quite a few rebreathers and it saddens me when someone is selling because they aren't that sure of the unit, some people take longer to get to grips with it than others but good skills and understanding will never be replaced with anything that can be manufactured. You can have the most tricked out CCR in the world but if you can't hold it together when the going gets tough then it's never going to be a happy ending.
I hate reading about the loss of a diver. I don't like reading about any indecent but if that makes diving that bit safer for me and if I can learn from it then I will and I'll try and pass it on.
Nobody wants to have these incidents and we all have an opinion, this is my opinion nothing more.
Dive safe.