Rebreather descent on Open Circuit?

[Mr.X]

I like first time posters on SB. No context related to the question. :blinking:

So, I think it's a very GOOD idea to descend to 200 feet on straight air, while dragging a separate rebreather with me (no flushing of loop) and to switch @ depth while forgetting to blow out water from the DSV while kneeling on the bottom inhaling PO2 over less than 7.0. Of course, I would use air dli and make sure I get a got hit of N2 while I'm at it. Since we're talking ridiculous why not drag a standard Gavin, three steel bottles and bolt cutters with me since I'm going to penetrate the China Room.

X

 

[floridagirl92]

Thanks for the advice! The reason I ask is because I have little experience in diving rebreathers. I am just logging some hours and my instructor told me that if I have troubles descending, that could make it easier. When I went diving with my friend who has quite a bit more experience, they looked at me like I was crazy when I told them that! So I wanted others opinions. Certainly don't want to be taking on any bad habits. If it makes any difference I am diving a Posiedon. Sorry I'm new at the forum. I've always been avoiding posting stuff on line but sound rebreather advice is hard to find and everyone seems to be so technical. I don't dive deeper than 130' anyway.

 

[Dsix36]

You might read some of the posts on rebreatherworld.com to gain some valuable knoiwledge.

 

[kierentec]

Thanks for the advice! The reason I ask is because I have little experience in diving rebreathers. I am just logging some hours and my instructor told me that if I have troubles descending, that could make it easier. When I went diving with my friend who has quite a bit more experience, they looked at me like I was crazy when I told them that! So I wanted others opinions. Certainly don't want to be taking on any bad habits. If it makes any difference I am diving a Posiedon. Sorry I'm new at the forum. I've always been avoiding posting stuff on line but sound rebreather advice is hard to find and everyone seems to be so technical. I don't dive deeper than 130' anyway.

sound rebreather advice can be difficult to find, however, I would hope your instructor would be a pretty good source for that kinda info. unfortunately that doesn't seem to be the case here, though. seems kinda lazy to tell you to drop on OC instead of helping you fix your problems. what problems are you having on your descent?

 

[Mr.X]

Glad that you provided context. Descending on OC and switching to CC brings with it a host of issues and defeats the idea of saving gas. CCR descents should be gradual, leisurely if possible and bubble / PO2 / sensor checks conducted along the way. I cannot see any competent CCR instructor telling you to switch from OC to CCR during descent unless you're bailing out, or performing a bailout drill/sanity check.


X

 

[wedivebc]

My advice is get yourself a different rebreather instructor. He is giving you bad advice.

Thanks for the advice! The reason I ask is because I have little experience in diving rebreathers. I am just logging some hours and my instructor told me that if I have troubles descending, that could make it easier. When I went diving with my friend who has quite a bit more experience, they looked at me like I was crazy when I told them that! So I wanted others opinions. Certainly don't want to be taking on any bad habits. If it makes any difference I am diving a Posiedon. Sorry I'm new at the forum. I've always been avoiding posting stuff on line but sound rebreather advice is hard to find and everyone seems to be so technical. I don't dive deeper than 130' anyway.

---------- Post Merged at 08:06 PM ---------- Previous Post was at 08:04 PM ----------

I think the OP is probably worried about spiking the PPO2, but it's a bad idea for the reasons given above. Also, on the chance that you missed something on your checklist, you might hear a gurgle on a slow descent on the loop, and be able to turn it and go fix it instead of putting the loop in your mouth on the bottom and having it flood there.

How would that help with spiking O2?

 

[1.3]

I've always been avoiding posting stuff on line but sound rebreather advice is hard to find and everyone seems to be so technical. I don't dive deeper than 130' anyway.

Your instruction based on the questons you are asking is very poor and you are getting awful advice. You need to stop diving the unit and get another instructor before you hurt yourself or compromise someone else attempting to help you. Were you even involved in the decision to choose the particular unit you are diving?

Contact Peter Sotis at: http://www.iantd.com/add/helium.html and explain what you have been doing and he will give guidance on how to proceed safely.

 

[floridagirl92]

Thanks all for the advice! I am going to close this thread now as I feel my questions have been answered. I really appreciate everyone confirming what I suspected. I thought his advice seemed strange at the time so I was following the protocol and standards I am learning by the book instead. At the same time as a new rebreather diver, didn't want to assume I knew more than anyone else. I would definitely use this medium to answer questions in the future. While some debate may be stirred, in the end I got the result I was looking for. Thanks again!

 

[1.3]

Thanks again!

You are welcome. Feel free to PM me if you have any questions.

 

[billgraham]

How would that help with spiking O2?

It wouldn't, other than the fact that it's not in your mouth.