Cheers for the info guys, ill have to see if I can dig out a copy of those service manuals.
I just spent the weekend diving this mask on my new mistral so I thought I would write up a wee report on it detailing my experiences with it in case its any use to anybody
1st dive - Cregan bridge - 55 minutes @ 5msw(16fsw)
My first dive on the mask I filled up the mask skirt fully with water the night before, though some leaked out. The mask was very easy to don even though I was wearing gloves. The mask sealed without me having to faff with anything despite me having a month or so worth of beard.
Impressions upon entering the water was that the field of view was somewhat narrow. At the point where the visor bends the view appears distorted and hazy. There is a long narrow vertical band on each side that you can see clearly out of. The mask was very comfortable on my face, after 50 minutes wearing it I felt no discomfort and the mask left no marks on my face.
The work of breathing was slightly affected by the mask. I noticed when the demand valve was above the level of the mouthpiece the corrugated section of the internal mouthpiece was drawn in before the demand valve cracked. Similarly when the mouthpiece was above the level of the demand valve the corrugated section of the internal mouthpiece was pushed out a bit before air was pushed out the exhaust valve. This was only very slight and after a few minutes I didn't notice it and I never felt that I was particualy struggling for air.
One thing I did notice was that the external mouthpiece had to be angled correctly or the internal mouthpiece tended to kink up which made it difficult to grip in the mouth. I found the ideal angle was about 45 degrees upwards. Wearing the mask to low on the face also seemed to cause the internal mouthpiece to kink up. I eventually figured out that if the point where the outer mouthpiece connects to the main body is to close to you (Caused by wearing the mask to low down) the mouthpiece has to turn through 90 degrees causing it to kink. Similarly having the external mouthpiece to near the horizontal means the internal mouthpiece has to bend in a z shape causing it to kink. Heres a rough diagram to show what I mean:
Original face picture taken from http://artrush73.hubpages.com
This made a big difference to comfort so id suggest anyone who tries one of these masks take this into account when getting it setup. I suspect if you get the one of these masks with the conshelf adaptor this wouldn't be a problem.
2nd dive - Cregan bridge - 4 minutes @ 5msw(16fsw)
This was a drift dive so gave a good chance to see how secure the mask was. Im pleased to say it didn't come off despite crashing into rocks, getting repeatedly kicked in the face by buddies and being flung around quite a few times. The mask skirt seems a lot bigger than on other full face masks ive seen, this means that even though I had it loose enough that I could tear it off my face with one hand it still sat very securely on my face.
I was concerned that the current might try to tug at the mask but I didn't notice this at all during the dive, despite appearing bulky its surprisingly streamlined!
3rd dive - Ballachulish - 35 minutes @ 30msw(98fsw)
This was my first time going deep on the mask. It behaved its self very well though I did wear the mask to low which meant with it kinked up I couldn't actually grip the inner mouthpiece it was just sitting in my mouth. Coming out of the water after the dive I moved the mask up slightly and this caused the mouthpiece to sit right again.
The mask gave no problems with regards to fogging. I spat on the visor before the dive then dipped it in seawater and it remained clear for the whole dive. More water leaked out of the seal overnight and it was now almost totally empty. On this dive I noticed the mask was not sealing around my beard very well, resulting in me being up to the bottom of my nose in water most of the dive. This wasn't a problem with the internal mouthpiece but it was rather chilly (Water temp 7c/44f).
I had put some black witch around the plug for the skirts filling nozzle but water from the seal is still leaking out around it so I will maybe take the plug off completely then see if I can do a better job of sealing it.
- I did not wear the nose plug on any of these dives, I found this allowed me to breathe in through my nose and draw air across the visor. This could be used to clear up any fogging which did occur.
- Using the mask with a twin hose seems to require a little bit of fiddling with angles and positions to get it nice and comfy.
- Getting water out the mask with the twin hose on was just a case of leaning back and opening my lips to allow the positive pressure air stream into the mask.
- With the internal mouthpiece the main airspace of the mask is not affected by variations in pressure coming from the twin-hose unless you want it to be. You can exploit this to clear the mask or suck it tighter against your face.
- the seal is absolutely brilliant, but only if you actually have water in it!
- I found it was possible to spit the mouthpiece out, yell at my buddies, then grab the mouthpiece with my tongue and put it back in my mouth.
- With regards to the above, if the mouthpiece is positioned badly and kinked up it can be quite hard to get it back into your mouth. (Particualy at 30 meters in the pitch black!)
- Overall I agree with YankDownUnder, its a brilliant mask and surprisingly easy to use!