John Routley modified his AGA mask to be fitted as a FFM on his Dolphin rebreather

John Routley managed to turn his AGA mask in a FFM for his Dolphin rebreather. Combined with the Nemotech oc/dsv mouthpiece this might be an interesting development.

Hi Janwillem very nice of you to get in touch. There was a lot of work to fit the two together safely. First I managed to get hold of an AGA mask that had had a rather nice conversion to fit a dolphin rebreather, but the round bit in the picture which is a quick removable bayonet fitting was machined to take the bite wing of a dolphin dsv but I managed to get hold of the blank in the picture with the small hole in the middle.

Next I needed to remove the bite wing from the nemo o/c dsv

And make a new plate which is identical to the bite wing plate but with out the bite wing on it( this was a lot of work as some special tooling was needed, but it just so happened I can have execs to most of what I need.  You can see the new mounting plate between the dsv and the mask bayonet, but this causes the first big problem, when you wear the mask the second stage digs you’re your chest so you have no movement when you look down

To get over this there needs to be a compromise in mobility and ease of water clearanceTo start I had to reverse the hole dsv so the second stage is on top not underneath

But this means some small changes to the dsv: reversal of the valves and the turning or removal of the scoop plate as the scoop when things are reversed starts to work against you.The problem with water being purged from the second stage is cured by tilting the head forward which make water removal much better.

With this configuration I have no problems with movement in any direction

 Now there a few problems I have encountered, the mask still had the gas path over the visor then into the nasal cup which works ok but if you had any resistance on exhale you get a back pressure which pushes bad gas back over the visor and starts a co2 loop, I took a hit about 4 weeks ago so can tell you its not pleasant and even if you bail to o/c on the mask it dose not help as the problem is still with you in the mask.

To stop this I have blocked the gas path over the visor and removed the valve in the centre of the conversion (seen in the first picture) then you need the reverse the valves in the nasal cup so the mask still equalises.

I find that I can not run min loop with the mask as it becomes uncomfortable when you inhale so I run a little more volume,

My only other problem is my face! And the mask vents to much gas but I have a fix for it, just need to get around to fitting some special  neoprene to the skirt.

I can still get the parts for the original conversion to the mask but the part I made for the nemo dsv was a one of the kind but a number of people have asked me to make more for the nemo and a few for BOB’s

So I may be persuaded yet.

Kind regards john routley

Ps I don’t have any more pictures of the parts I made but can do some if you need them

 This is the mounting plate I made, this bolts straight on to the Nemo dsv and on to the AGA conversion made by  Gil Knott of Saga Ventures LLC.

I didn’t use Gils original conversion as his convertion is made just to take a standard dsv not a oc/dsv which is much heavier and I was worried that it only used one wedged o-ring to hold the dsv in the bayonet fitting

So I got from him a blank bayonet fitting which would normally have a machined hole in it for the dsv bitewing

I decided that it needed to be stronger

I decided that it needed to be stronger and bolting the dsv to the mask was in order

If you want additional information you can contact John Routley (NARKED AT 90) here

John, thank you very much for your contribtution to my website!