GEM recreational rebreather

[Walt Stearns]

To clarify the connection between the KISS GEM and the Shearwater dive computer.

When applied to a KISS fully closed (CCR) rebreather like the Sport, Classic or Explorer, the computer reads the three oxygen cells in the CCR. Connection between the cells and and computer is carried out by a single cable that is Hard wired to the CCR (inside the scrubber head, the cable is split off with two wires running to each 02 sensor) with the other end, via a fischer connecter is plugged into the shearwater computer on your wrist.
That is the general configuration on a CCR.

With the GEM (a semi-closed rebreather - SCR) the same Shearwater computer (placed in SCR mode) is connected via a fischer cable just like the one in the CCR, with one exception that it is only going to read one cell, which is all that is needed with the GEM, to monitor your PO2 and FO2, which it applies the information into the computer’s algorithm during the course of the dive.

While certainly not dainty on the wrist, the Shearwater is great computer, in addition to using the Predator model with my KISS Explorer, I use it for extended range open circuit dives and now will be using on my GEM when I receive it next month.

Now, if you think the Shearwater computer is not for you, or at the moment a little pricey for your wallet, the GEM works perfectly fine using the standard KISS PO2 display monitor (which you can replace with fischer cable later) and your current Nitrox computer. After all, when diving SCR, you are pretty much diving a single FO2 percentage (give or take 3%) the entire time.

[debersole]

I agree completely with Walt. The GEM is an outstanding option for the recreational diver who wants a "gas-extender" with the added benefit of breathing warm, moist air, and minimal bubbles. For those divers who already own a Shearwater computer for their other diving, the GEM with a Fischer cable is a great option. However, for the average recreational nitrox diver the GEM with the single Jetsam PO2 display and their usual nitrox computer (set to 3-5% lower FIO2 than what is in their cylinder) works very well as this is marketed as a recreational, no-decompression diving system. Some people enjoy it for the warm, moist air and minimal bubbles (me), some due to the fact they can dive a small and light alumimum 50 cylinder and EASILY get in two long dives (my wife), while others like taking an aluminum 80 and doing a two tank trip in the morning and a two tank trip in the afternoon on the same cylinder! This is a very versatile unit -- and, from someone who dove and taught the Drager Dolphin for years, it is nothing like a Drager.

Doug

[W8less]

Non technical question, Any one have any experience with the GEM on dive trips, ie; racking on dive boats, general treatment by resort DM's

[Stever222]

I brought my GEM to Bonaire last fall with no problems at all. I carried the whole unit including BC in its bag as carry on and packed a couple of canisters and the rest of my gear in my checked baggage. At first the dive operator wanted to load all the tanks on the boat and have me set up my gear once I was aboard. With the short boat rides this did not work at all so I set up everything ahead of time and carried the complete package onto the boat my self. By the end of the week they were used to this. I asked about nitrox percentages when I first arrived and was told they only had 32% so I used that all week. On the last day while talking to the manager he told me they would mix what ever I wanted. Apparently everyone was not aware of this. To sum it up it was a great week of diving the GEM and I met a lot of people curious about the rig I was diving with. I am sure mine was the first GEM the dive operation had seen.

[debersole]

Steve (above), Bob Ferguson, and I will be diving GEMS in Palau and Yap for the next couple of weeks. We leave Thursday. We can give you more updates when we get back. We shipped cartridges ahead and have been told we can get EAN 32 or EAN 36.

Doug

[divejay]

Non technical question, Any one have any experience with the GEM on dive trips, ie; racking on dive boats, general treatment by resort DM's

The GEM does not require any more room in the dive boat rack than open circuit with a pony bottle attached to the dive tank. DM's at resorts are very curious and after a week of watching you dive it they will want to buy it before you leave.

[NetDoc]

It looks as if it's made to sidemount easily. Any thoughts on that?

[Dive-aholic]

The only issue with sidemounting is the counterlung and loop positioning. I have been clipping the canister on similar to a stage cylinder and it keeps a low profile in back. I have some mods in mind for getting the counterlungs moved to a different position. Already have what I need to make it happen just haven't had time to make it happen.

[debersole]

Pete:

Mike Young (the inventor of the GEM) has a prototype sidemount GEM that he is working on. Some cave divers (Brett Hemphill and Curt Bowen) tried it out last fall around DEMA and the NACD meeting. Apparently it still needs some "tweaking" to get the work of breathing right as Rob mentioned above.

Doug

[NetDoc]

Sounds cool... I would love to see it, or at least see some pictures.