deco question

[Ron Ravenhill]

hi guys

i have never used a rebreather before and have very little knowledge about them however the drager unit is starting to appeal to me for several reasons.

Anyway if i did a dive with the drager to 30m. How much additional no stop time would i have over my buddy who was on OC with the same nitrox mix say 32%?

cheers

[wreckweasel]

.

[NotDeadYet]

You'd use EAN40 as drive gas with the appropriate jet. It would give probably in the region of EAN31 or 32 being breathed in the loop so you wouldn't actually be gaining anything over your buddy.

I don't really see the point of SCR other than as a "I want one" bit of kit. It costs more in capital/training, maintenance and consumables than open circuit with added inherent risks (Dolphins have no clear failure modes, it can malfunction with no warning but you can still breathe from it without knowing any different -- til you pass out that is). It's quieter but so what?

[nigelH]

Originally Posted by Ron Ravenhill

i have never used a rebreather before
and have very little knowledge about them
however the drager unit is starting to appeal to me for several reasons.

Everybody starts with the first bit.
Fix the second bit
and the third will go away.

The only time I've seen a Dräger used for deco diving the guy didn't bother with stops and went home via Coastguard Airways. I have yet to be convinced of the game plan for a Nitrox Semi-Closed system. It doesn't offer much or any advantages over OC diving but for more money. If you and your buddy both have optimum mix for depth then he will get less stops on OC.

[questar]

Originally Posted by Ron Ravenhill

hi guys

i have never used a rebreather before and have very little knowledge about them however the drager unit is starting to appeal to me for several reasons.

Anyway if i did a dive with the drager to 30m. How much additional no stop time would i have over my buddy who was on OC with the same nitrox mix say 32%?

cheers

With a standard work rate using a 40% mix, on the 40% jet you will be breathing around 32%, but your MOD will be limited to 30M. Your buddy's MOD will be 40M. MOD's are based on what's in your tank, not what you breath.

Deco obligation and bottom times will be the same because these are worked out on what you are breathing, not what is in your tank. When you do a scr course, you are taught how to work out what you are breathing mix will be.

ATB

Tony

[Mark Chase]

Originally Posted by Ron Ravenhill

hi guys

i have never used a rebreather before and have very little knowledge about them however the drager unit is starting to appeal to me for several reasons.

Anyway if i did a dive with the drager to 30m. How much additional no stop time would i have over my buddy who was on OC with the same nitrox mix say 32%?

cheers

No advantage over OC dont bother with a drager and get a proper CCR which WILL give you an advantage.

KISS or YBOD S/H is a good start to see if its for you.

ATB

Mark Chase

[Ron Ravenhill]

So whats the point in having a semi closed if you dont get any additional no stop time over an oc setup. I was getting into my twins recently and was planning on a season of diving in the 30/35 metre range on nitrox and slowly getting involved with a little deco.

Unfortunatley i recently developed a DVT deep vein thrombosis and will not be able to dive for six months which has scuppered my plans I think i will dive again but cant be sure. One thing is for sure i wont be putting a twinset on again but i still want to achieve my goal of doing extended dives 30/35 meters.

I need a lightweight system which is not rocket science and is safe. I have 90 dives so still a novice?

Can anyone help

[Mark Chase]

Originally Posted by Ron Ravenhill

So whats the point in having a semi closed if you dont get any additional no stop time over an oc setup. I was getting into my twins recently and was planning on a season of diving in the 30/35 metre range on nitrox and slowly getting involved with a little deco.

Unfortunatley i recently developed a DVT deep vein thrombosis and will not be able to dive for six months which has scuppered my plans I think i will dive again but cant be sure. One thing is for sure i wont be putting a twinset on again but i still want to achieve my goal of doing extended dives 30/35 meters.

I need a lightweight system which is not rocket science and is safe. I have 90 dives so still a novice?

Can anyone help

Sport KISS CCR small, lite, relitavly cheep, very simple to dive and it can be used to depths most divers never go to.

This would be my first choice.

http://www.jetsam.ca/mod.php?mod=use...=22&page_id=29

SCR has most of the dangers of CCR diving and few of the advantages.

ATB

Mark Chase

[Ron Ravenhill]

hi mark

thanks for the info. any idea how much one of these with the course would be and what quals would i need?

[smudger]

Originally Posted by Ron Ravenhill

hi guys

i have never used a rebreather before and have very little knowledge about them however the drager unit is starting to appeal to me for several reasons.

Anyway if i did a dive with the drager to 30m. How much additional no stop time would i have over my buddy who was on OC with the same nitrox mix say 32%?

cheers

I have to agree with other post the SCR is more of a gas extension piece of kit but overall it does not have many advantages over O/C diving. The ones that I have seen are relativly heavy, so not much advantage there, I couldn't see an advantage too them particularly as a twin set can be used so you have better bailout options, less bubbles yes but if you are looking to invest that amount of money why not look at the 2nd hand CCR market and if you really want too use it semi closed.
You can run a CCR more efectivly on Nitox if that is your aim, Also if you are looking for a SCR because you are heavy on gas the CCR is deffinatly a better option.