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IST Full Face Mask

Discussion in 'Fins, Masks and Snorkels' started by Euroboy_DC, Jun 7, 2010.

  1. Resqdivemedic

    Resqdivemedic Public Safety Diver

    # of Dives: 100 - 199
    Location: chepachet, RI USA
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    Take a look at the OTS Spectrum. You can add your own regulator to it. I have been diving one for 3 years now and it has been great.
     
  2. Bigbella

    Bigbella ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: San Francisco
    1,024
    1,039
    113
    I have used the Poseidon Atmosphere, for years; though, I have tried others -- some of which honked, underwater, like Canada geese; or, else breathed like having a pillow pressed over one's face. It was also the model most commonly available to us at UC and Cal State back then.

    While at school, I once took a Summer job, replacing zincs, at a local harbor; and having temporarily "lifted" the "positive" or "over-pressure" mask from class, remained hepatitus-free, in an area, notorious for illegal live-aboards; and the mask -- then, my own -- also proved effective, years later, while collecting sediment samples for laboratories, in such garden spots as septic Oakland Harbor, below the giant cranes of Schnitzer Steel. I still prefer the positive pressure and ventilation to the on-demand masks; they are near-impossible to flood and never fog.

    A major drag with FFMs, though, is the issue with varying buoyancies, dependent upon the model of mask, hood, and depth; and the need for expensive ballasts, to correct for it. A tunnel vision effect is also quite common with common visors -- especially with the use of some weights, which is almost like wearing blinders.

    I still commonly use my masks, especially if the temperature goes much below 10˚ C; or, if there is some heavy wave action . . .
     
  3. Ghost95

    Ghost95 Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Florida
    509
    553
    93
    I have a real concern with that mask. It has a large internal volume and if you are using shallow breaths through your nose I believe that there can be a build up of CO2 in the mask.

    I had an experience with that mask while diving at 40'. I was moving slowly, not expending much energy and very relaxed. I started to feel "off", a little light headed, and a couple stars showed up in my vision. I realized something was not right and started swimming back to the beach. I vented the mask and started heading back to shore. As soon as I started breathing heavier all the weird feelings went away.

    Can I be sure that the mask had a CO2 build up, no but i feel that is what happened. I've heard reports that those FFM's with the snorkel coming out of the top have caused some similar issues including people blacking out.

    I still dive the mask, just not solo. Be careful.
     
  4. Bigbella

    Bigbella ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: San Francisco
    1,024
    1,039
    113
    To whose mask are you referring (the OP's choice?); and / or was it adjusted or maintained properly?

    Mine is well-ventilated, "shallow-breaths" or not . . .
     
  5. Ghost95

    Ghost95 Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Florida
    509
    553
    93
    The link in the OP didn't work but I think it was this https://www.amazon.com/IST-PEGASUS-Commercial-Diving-Attachment/dp/B0756GJGPK . Mine was rubber not silicone. The mask zip ties to the regulator with no mouthpiece. The entire inside of the mask is one large space. When breathing through my nose and just crawling along the bottom, not working very hard, there didn't seem to be much gas exchange. Breathing technique was my fault but the volume of the mask, I feel, could possibly contribute to CO2 build up leading to the weird sensations I experienced. It happened twice, once solo and once with a buddy. Both low stress bottle dives without much activity. On active dives with a higher gas consumption it has not been a problem. All of this may have been my technique but I have only experienced this with this full face mask. I got to dive an Ocean Reef and an AGA mask a couple times and were an all around better mask but way more expensive.

    I have a buddy who is a commercial diver and he explained that when using the regulator with a mouthpiece the air is delivered directly into your mouth where as with a FFM it's delivered into a larger space. Depending on the volume of breaths and how air circulates it seems that a CO2 build up is a possibility. The commercial masks, and the Ocean Reef have an oral nasal cup that keeps the gas contained in a smaller volume for this reason.

    I could very well be wrong about the mask contributing to my experience but I haven't been able to rule it out either. I'd love to hear more about the subject. I'm always open to new thoughts on how to make things safer, especially for solo dives.
     
  6. Ghost95

    Ghost95 Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Florida
    509
    553
    93
    If this is your mask, www.amazon.com/Atmosphere-MK3-Full-Face-Mask/dp/B00BOEV8IO, Nice! It looks very much like the AGA mask I got to play with. My buddy's mask had a QD for the air and some sort of gas switching block that allowed another gas line to be fed to the regulator. He had these two HP tanks that were manifolded and were crazy heavy for as small as they were. I think he said they were like 4000 or 5000 psi or something like that. Fun commercial gear.
     
  7. Bigbella

    Bigbella ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: San Francisco
    1,024
    1,039
    113
    IMG_2474.JPG
    From a related thread, "A distinction should be drawn between conventional "on demand" FFMs and those which are "over-pressurized" or "positive pressure," which, basically, free-flow a bit, into the mask, and allow for a slight, though continuous flow of venting air, such as some OTS models and the Poseidon Atmosphere, which I have used for years, at considerable depths, without any issues whatsoever" . . .

    Yeah, that's it; and, wow, at the highest damn price that I have ever seen for the thing -- not remotely what I paid.

    I, too use a switching manifold for multiple tanks.

    Both the Atmosphere and the AGA / Interspiro, that you mentioned, share the same Swedish design origin; and I've used both. As you can see, in the photo, the oral-nasal portion of the mask is snug and somewhat isolated from the visor, which allows for little gas accumulation; and I have had yet to experience any CO2-related symptoms, in decades of use, regardless of, either my position in the water; depth; my workload; or any breathing habits.

    The regulator, itself is a positive-pressure variant of the Poseidon Jetstream (essentially replaced with the guts of an Xstream) and designed to lightly free-flow . . .
     
  8. Ghost95

    Ghost95 Manta Ray

    # of Dives: 1,000 - 2,499
    Location: Florida
    509
    553
    93
    The AGA was allot of fun to play with. The mask in the OP has no oral-nasal separation from the rest of the mask, it's all one open space. Maybe that matters maybe not for CO2 in real world diving. It's the only thing I could come up with for my weird experience.

    I preferred the AGA style over the Ocean Reef for the short time I used them because the Ocean Reef regulator seemed to stick waaay out from the mask and had more drag if you turned your head in any current.
     

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