Newbie Deco Questions...

[smudgegs]

Hello all!

I've just qualified on the Dolphin, though I haven't got one.... yet so I'm still diving twin 10 or twin 7's

My question basically is: Why don't Drager reccomend planned deco?
Is it purely because of the linited bailout in a standard set or is there a more involved reason which I'm unaware of?

tbh I found it quite frustrating to dive because as a package it seems aimed at shallo warm water reefs yet I found it worked best below 20m, which is also where the extra duration etc would be most useful *if* it was fitted with decent sized bailout(s) and a wing/bc which could lift it. I was very surprised how marginal the buoyancy of the standard jacket is!
It has such potential too.... (yup I've already seen the tecme site... now that ss shell is what apeks should be selling it in imho! Oh and without the std jacket/harness and about £1k cheaper than they're asking... they'd sell thousands if they did that imvho)

Anyway, enough rambling. Hello all and please feel free to tell me why I've got it all wrong

Smudge

[NotDeadYet]

I'd imagine it's a liability thing. If it all goes wrong, bail to OC and head for the surface. It's pitched at the floaty reef crowd so it would need the introduction of another course to cover the liability issues, I guess they don't want the aggro.

[smudgegs]

Yes but they don't need to run another course...?

As I say, assuming there is no other reason for the "no deco" rule other than the limited redundancy offered by the 3l pony

Certainly where I did my course you had to be DL qualified and advanced nitrox (or equivalent). So anyone learning on the set *should* be pretty confident about planned deco etc.
Oh and yes, as a standard package the Dolphin has limited bailout and extremely marginal lift... BUT all they have to do is say something along the lines of

"planned deco may be permitted subject to the diver/s being qualified in such practice, equiped with buoyancy compensators with suitable lift, and carrying sufficient bail out gas to ensure a safe return to the surface. No liability can be accepted by the company for such action and it is entirely at the discretion of the divers concerned".

That and perhaps selling the shell & breathing loop/bags/scrubber at a sensible price for fitting to an existing wing/bc/harness.

Being honest, having looked long and hard at the set I believe it to be about £1k overpriced when compared with OC sets of comparable complexity and quality. Which is a damn shame as I believe it has many advantages

[jar_uk1]

I am in my first season of diving with the drager, and love it, although I never seem to get to dive as much as I would like.

As standard I just dont think the unit is really suitable for deco diving and when on oc I managed to do a fair number of dives round about the 40m mark that gave me some long deco times. You simply would not consider doing that sort of dive on a standard Drager.

I guess though that not many dragers are completely standard, on mine the loop is obviously untouched but I do use a backplate adaptor, dive-rite harness, Agir Wing, VR3, 10L with H valve and I have just started to dive with a sidemount 7L bailout - purely intended for the deeper dives, as it allows me some flexibility in my gas choice

While I feel that my setup would probably be suitable for a certain level of deco diving, I am aware that Drager do not recommend it. Also the fact that the unit is only CE approved when it is standard, COULD have implications if the shit hits the fan, and people have to deal with the fallout afterwards?

I have not done any "real" deco yet and am still finding simulated stops a pain at the shallowest depths, so I would want to be a lot more comfortable here before I even think about real stops.

John R

[Freeflow]

The CE marking is for the supply of goods, and any mods will invalidate the CE certification.

This means ANY mod, so although my rig is fairly standard, the bungee loops and waist pouch invalidate the CE mark. As did simply changing the two part waist buckle for a weightbelt type one.

I have deco'd my Dolph using a 7L stage as suit gas and deco gas. The stage mounts on the left as opposed to the right to balance the 3L pony.

35m for 25 min was 11 min of deco, swap to 50% at 21m, turning off the Dolph tank and breathing the loop down to remove the gas-this prevents the loop gas expanding too much on ascent and changing the buoyancy too much.

[gibbon]

Originally Posted by Freeflow

turning off the Dolph tank and breathing the loop down to remove the gas-this prevents the loop gas expanding too much on ascent and changing the buoyancy too much.

FF presumably you mean 50% on OC? what size cylinders do you dive with and what durations do those give you with what mixes/orrifices?

[Freeflow]

I use the 60% jet pretty exclusively and match the cylinder % to the dive I am doing. I have a low vO2, so hyperoxia rather than hypoxia is usually a problem for me. If you lean the mix too much you have a very narrow window of acceptable oxygen use. Using this jet will give me 172 minutes fo gas from full to empty on a 5L / 200 bar tank.

For deco I use a single 7L / 232 bar which gives 1600+litres / about 52 [I think] cu ft of gas.

I have soem spreadsheets you might find useful, drop me an email.