Zachyamauchi
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Is it possible/common to dive a sidemount rig with multiple cylinders while using a full face mask like an ocean reef Neptune? If so, how are gas switches done?
Thanks
Zach
Thanks
Zach
Full face mask for sidemount
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possible yes, common no.
Two ways
Option 1-you can use a gas switch block from Omni-swivel and treat it like a bailout, so you switch back and forth between the two on your gas switches. You need QD's on this to plug into the FFM so the bottles aren't tied together permanently. Cost for a pair of bottles is about $500. $100 for the high flow QD's, and about $300 for the switch block.
Option 2-UTD manifold block. Cost is about $600 and again you need quick disconnects on all bottles, so that cost is for 2 bottles.
Either option you need to have a way to isolate the FFM and use a normal second stage in case of a failure so you either have a second stage on a QD somewhere, or you have second stages on each bottle in addition to the QD. Very expensive and cumbersome to deal with. Single Tank Sidemount is obviously much less complicated to deal with, but you're largely limited to AL80's and since your SAC rate goes up considerably on a FFM, it isn't practical. Unless you have a very specific need to dive sidemount and a FFM I would choose one or the other.
Two ways
Option 1-you can use a gas switch block from Omni-swivel and treat it like a bailout, so you switch back and forth between the two on your gas switches. You need QD's on this to plug into the FFM so the bottles aren't tied together permanently. Cost for a pair of bottles is about $500. $100 for the high flow QD's, and about $300 for the switch block.
Option 2-UTD manifold block. Cost is about $600 and again you need quick disconnects on all bottles, so that cost is for 2 bottles.
Either option you need to have a way to isolate the FFM and use a normal second stage in case of a failure so you either have a second stage on a QD somewhere, or you have second stages on each bottle in addition to the QD. Very expensive and cumbersome to deal with. Single Tank Sidemount is obviously much less complicated to deal with, but you're largely limited to AL80's and since your SAC rate goes up considerably on a FFM, it isn't practical. Unless you have a very specific need to dive sidemount and a FFM I would choose one or the other.
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Zachyamauchi
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That's what I thought. Why don't more tec divers dive with ffm's? Is it a higher risk of failure or just logistically more complicated
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they are incredibly complicated to dive with because of the gas switching. Very little need for comm support unless you are on specific working dives so it is easier to go without. Part of the reason I dive with the guys that I do is because it is an escape from any sort of talking, which they say about me as well, so once you dive with a FFM you can talk to each other and it removes part of the peace of being underwater.
FFM's are nice, I really like using them, but they are just very complicated to deal with because of the quick disconnects, switch blocks, spare regulators, higher gas consumption rates, etc etc. FFM's are a very specific tool, and there are few exceptions where they make sense to use on a regular basis. I would look at what you want to do with your diving and see if a FFM aligns with those goals, and if sidemount aligns with those goals. One will prevail over the other, and if that is sidemount, you can always use FFM with backmount when you need to. If it is FFM, then unless you have back/joint problems that cause you to have to dive sidemount from a health perspective, or you are planning on going through a lot of flat bedding planes and bottle off restrictions in caves, then I would recommend staying with backmounted doubles.
FFM's are nice, I really like using them, but they are just very complicated to deal with because of the quick disconnects, switch blocks, spare regulators, higher gas consumption rates, etc etc. FFM's are a very specific tool, and there are few exceptions where they make sense to use on a regular basis. I would look at what you want to do with your diving and see if a FFM aligns with those goals, and if sidemount aligns with those goals. One will prevail over the other, and if that is sidemount, you can always use FFM with backmount when you need to. If it is FFM, then unless you have back/joint problems that cause you to have to dive sidemount from a health perspective, or you are planning on going through a lot of flat bedding planes and bottle off restrictions in caves, then I would recommend staying with backmounted doubles.
Here is what those systems look like...
PSTD Equipment Configuration Overview - Public Safety Team Diving
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PSTD Equipment Configuration Overview - Public Safety Team Diving
Sent from my iPhone using Tapatalk
Another approach is to you a mask like the Kirby Morgan M48. It's probably the most flexible option for a technical diving full face mask as you can detach the lower pod to use other second stages.
Oceanic sold the same mask as the JMC Supermask, and Hollis sells a version as the Mod-1.
The mask uses a standard second stage that is inserted in a detachable pod that clips on the lower portion of the mask. The pod that can be detached, allowing you to either breathe directly from another standard second stage, or you can attach another second stage with a second pod.
With a pod reattached, you can immediately breathe directly off the mouthpiece, then dewater the pod with the purge valve. Once the pod is dewatered, you can breathe and/or talk normally. The mask and pod has provisions for com equipment.
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I used to use one for inland commercial diving,in part because it was a lot lighter, a lot lower volume and a lot less buoyant than my Kirby Morgan EXO-26. I used an M&J gas block to allow an alternate gas source, with no need to remove the lower pod.
I also made a few Great Lakes wreck dives with it as well as a large number of ice dives, but it's still a fairly complicated system and not something I'm tempted to use in warmer water technical diving, and I wouldn't even consider it for cave diving.
Oceanic sold the same mask as the JMC Supermask, and Hollis sells a version as the Mod-1.
The mask uses a standard second stage that is inserted in a detachable pod that clips on the lower portion of the mask. The pod that can be detached, allowing you to either breathe directly from another standard second stage, or you can attach another second stage with a second pod.
With a pod reattached, you can immediately breathe directly off the mouthpiece, then dewater the pod with the purge valve. Once the pod is dewatered, you can breathe and/or talk normally. The mask and pod has provisions for com equipment.
----
I used to use one for inland commercial diving,in part because it was a lot lighter, a lot lower volume and a lot less buoyant than my Kirby Morgan EXO-26. I used an M&J gas block to allow an alternate gas source, with no need to remove the lower pod.
I also made a few Great Lakes wreck dives with it as well as a large number of ice dives, but it's still a fairly complicated system and not something I'm tempted to use in warmer water technical diving, and I wouldn't even consider it for cave diving.
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I've never liked those just because if I'm on FFM I do much prefer to breathe through my nose.... Is an option, but really no cheaper than a normal FFM with a switch block, albeit a lot easier to equalize since you can pinch your nose off. It is a helluva lot easier than the exo26 though, those things are colossal.
Kirby Morgan = $$$$$$
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While I love diving my FFM for back mount recreational diving that doesn't require gas switches, I find any potential solution to gas switching with the FFM to be woefully cumbersome. So with that in mind most of my extended range diving is done with the good old fashioned bite regulator.
I tried a FFM in sidemount once and have been thinking about ways to use them ever since.
Some people prefer them, but a few cannot dive comfortably without one at all, due to disabled facial nerves for example.
In my opinion the most obvious solution is using them with large single tank configurations with the second tank configured as a kind of bailout stage.
It could carry a quick connect for the FFM, but mostly it needs a normal second stage. I would also add another of those to the main FFM reg.
That way you use your main tank as the first two thirds and the other one for the last plus a large margin off error.
In any emergency you can switch to a bailout second stage to breath and put on the normal spare mask.
Should be enough to fix problems the FFM might have when switching quick connects or connecting to a simple LP manifold that is only connected or turned on in emergencys.
Another option is using it like some people use two hose regulators and small rebreathers: backmount it.
A single backmounted tank with the FFM and two slim and streamlined sidemounted bailouts.
Could carry quick connects again and normal first stages as dedicated backups, perhaps with small masks bungeed directly to the tank as well.
Some people prefer them, but a few cannot dive comfortably without one at all, due to disabled facial nerves for example.
In my opinion the most obvious solution is using them with large single tank configurations with the second tank configured as a kind of bailout stage.
It could carry a quick connect for the FFM, but mostly it needs a normal second stage. I would also add another of those to the main FFM reg.
That way you use your main tank as the first two thirds and the other one for the last plus a large margin off error.
In any emergency you can switch to a bailout second stage to breath and put on the normal spare mask.
Should be enough to fix problems the FFM might have when switching quick connects or connecting to a simple LP manifold that is only connected or turned on in emergencys.
Another option is using it like some people use two hose regulators and small rebreathers: backmount it.
A single backmounted tank with the FFM and two slim and streamlined sidemounted bailouts.
Could carry quick connects again and normal first stages as dedicated backups, perhaps with small masks bungeed directly to the tank as well.
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