New Halcyon Rebreather?

[kammel78]

Not wanting that to derail this excellent thread; by travel-oriented, I mean looking at pretty fish without "team" diving and the traditional large and heavy kit. For example, using the very lightweight Halcyon Symbios on the barrier reef as it's nicer to dive CCR than OC.

Hope you're right about the price!

I'll add that a chesty, in general, works great for your use case, especially from a dive ops perspective. I've talked a number of OC-only blue water dive ops into letting me dive my chop with my family/friends since they don't have to do anything different for me...just give me an AL80 like everyone else. All I have to do if find a shop somewhere (sometimes it's the dive op) to refill my O2 bottle every other day.

 

[Wibble]

I'll add that a chesty, in general, works great for your use case, especially from a dive ops perspective. I've talked a number of OC-only blue water dive ops into letting me dive my chop with my family/friends since they don't have to do anything different for me...just give me an AL80 like everyone else. All I have to do if find a shop somewhere (sometimes it's the dive op) to refill my O2 bottle every other day.

Do you fly with your O2 bottle?

(My use case for a chestmount is that it's light for travel (of course there's the additional BP+W or sidemount+wing) and it's usable in overhead environments and wriggly ones to push through in front if necessary. This unit could well fit the bill.)

 

[kammel78]

Do you fly with your O2 bottle?

(My use case for a chestmount is that it's light for travel (of course there's the additional BP+W or sidemount+wing) and it's usable in overhead environments and wriggly ones to push through in front if necessary. This unit could well fit the bill.)

Yep. I take the valve off so they can see it's empty and put saran wrap over the open end.

I dive both OW and caves with it. OW is single tank bm, cave is sidemount. It's certainly not my favorite for caves, winder-style is my favorite from a profile perspective, but the chest mount was the only that covered both use cases for me. Feel free to pm me if you have any other questions or there're plenty of other threads on opinions of cm vs sm vs bm ccrs.

 

[lostsheep]

How's the accessibility of the drysuit inflator valve with ring system?

It’s a non issue

 

[Tobias24]

Any news about the training Programm and Release date?

 

[SavageSeaCow]

Any news about the training Programm and Release date?

I stopped by EE in high springs and got to take a look at it in real life. Seems like they are starting to train and distribute! Chest mount isn’t for me but it seems well built with very cool tech.

 

[travisfull]

In the latest number of GUE magazine Quest, besides talking about the Symbios from a technical standpoint, John Kendall confirms thar GUE will offer CCR training with Symbios within 2025.

 

[Stevegriscti]

Looking at the patent (assuming it's the one implemented in Symbios), the unit can be divided into two parts - an "outer loop" consisting of the DSV, inhale hose, exhale hose and the gas block. And an "inner loop" with CLs and Scrubber (incl. sensor head). The gas block contains a OPV, combined ADV/BOV and valves in the gas block that can isolate the outer loop from the inner loop.

In OC mode the inner and outer loop are isolated from each other, which means gas can only come from the BOV/ADV, pass through the DSV, and exit via the OPV in the gas block. Btw, when you switch to OC, the spring pressure on the OPV exit valve is removed and it will work like any 2nd stage regulator exit valve.

In other word, regardless if the one-way valves are defect (or even missing) and provided the outer loop is not leaking, inhalation gas can only come from the BOV demand valve. While exhale gas can only exit via the OPV exit valve. Since the inner loop is blocked the volume is constant. The only re-inhaled gas will be in the DSV - more or less the same volume as any 2nd stage regulator.

To me it looks very ingenious, and implemented right it should breath very well in OC, with a slight extra effort to exhale (you will have to push gas down to the gas block to exit).

But there is one thing that bugs me. Both the valves isolating the inner and outer loops close outside-in. This means that negative ambient pressure (-0.1 bar to -1 bar) in the inner loop will force the valves open. In other words, if you descend in OC mode (BOV closed, DSV open) they will act as internal OPV between outer and inner loop and equalize pressure between the loops. All well and fine.

However, if you ascend with BOV closed (DSV open or closed does not matter) the pressure in the inner loop will increase with no way to exit. Since the valves between inner and outer loops will seal shut if the pressure in the inner loop is higher that the outer loop, this means it might be impossible to return to CC and vent any over-pressure. Eventually the inner loop will rupture.

Solution could be a separate OPV in the inner loop. A better solution would be if the exhale valve could close from the inside-out (instead of outside-in). The exhale valve could then act as OPV if the inner loop pressure is significantly higher than ambient pressure, while the inhale valve would act as OPV if the inner loop is significantly lower than ambient pressure. The latter solution would not require any additional components.

Bit late to the party, but there' a 5th opening at the chest block which is an opv