Recommended options on new rebreather (Optima CM)

[LFMarm]

Would like to get the experts opinion on which options to get with a new Optima CM. Here are the ones I identified so far:

• Nerd 2 as controller paired with HUD — no cables going to the wrist
• XT1 first stage — rotating turret
• Upgrade the ADV/MAV to a high flow quick disconnect QC-6 fitting —recommended for diving deeper than 40m
• pull dump to replace the bulky drysuit style dump for the counterlung
• Shut off on oxygen line

Do these make sense to you?

 

[J-Vo]

Are you planning to use the NERD and a HUD? Sounds a bit cluttered.

 

[LFMarm]

Are you planning to use the NERD and a HUD? Sounds a bit cluttered.

Yes, I like the idea of all the cables being self contained on the rebreather with nothing going to the wrists

 

[inquis]

Are you planning to use the NERD and a HUD? Sounds a bit cluttered.

I believe that is the stock configuration. Tradeoff between clutter and ease of reducing the vertical profile (supermanning)?

 

[grantctobin]

I believe that is the stock configuration. Tradeoff between clutter and ease of reducing the vertical profile (supermanning)?

Stock is wrist unit and HUD unless it’s changed.

I’m not a believer in oxygen shutoffs, particularly on an eCCR. The oxygen on a Choptima is not something you’ll ever be unable to reach and turn off. It’s also easy to add in-line later.

There’s nothing inappropriate with a standard inflator nipple for deep (100M) diving unless you’re planning to use your ADV as a second stage (open loop). I’d choose QC6 vs not based on what your teammates are using. If everyone is using standard inflator nipples and you’re not using a BOV, I’d stick with the standard bc qd.

The dump upgrade is worthwhile. I can’t remember if the current ones include the knife in the front Z-knife pocket, but would make sure they do or order one.

I don’t think the swivel first stage adds anything to the unit but if you’re keen to upgrade so be it.

I’d grab one of the highland/XS Scuba adjustable OPV rather than the normal stock one and ensure you have a few spares on hand.

 

[J-Vo]

I believe that is the stock configuration. Tradeoff between clutter and ease of reducing the vertical profile (supermanning)?

Interesting, I think I would be tempted to run the NERD and strap a Petrel to the back of the unit to pull out if the NERD conks out..

 

[J-Vo]

There’s nothing inappropriate with a standard inflator nipple for deep (100M)

I agree and this is what I use. I have however found that some LP hoses are flow restricted and can not provide enough gass.

 

[DiveTucson]

Standard first stage is the FT1. It routes the houses will for the onboard O2. Of all the units I have configured for folks I have never seen one done with XT1 honestly.

I much prefer the NERD with HUD which is one of the current stock configurations. The HUD is stowed out of the way unless there is an issue with the NERD. As discussed above there is no wires then going to the diver which keeps things nice and clean.

The pull dump OPV is much smaller than the standard OPV and I put that on pretty much every unit I build.

 

[stretchthepenn]

Are you planning to use the NERD and a HUD? Sounds a bit cluttered.

As @DiveTucson noted, the HUD is stowed out of the way. Its cable passes into a hole on the lower-left backside of the counterlung assembly (between your chest and the left/inhale counterlung), forms a loop, and then emerges from a hole at the top-left backside of the assembly.

Next to the top-left hole, there's a nylon loop that controls the strap-and-boltsnap combo you use to clip the unit to your harness. A quick-release bungee (or something similar) loops around that strap and holds the HUD.

The HUD display sticks up like a short antenna above your left pec. It's high enough that your buddy can see the readout but low enough that it remains out of your visual field.

If you need the HUD, then grab the head, pull on it, and clip it onto the left side of your NERD's bracket.

The photo below illustrates the routing I described:

 

[stretchthepenn]

I’m not a believer in oxygen shutoffs, particularly on an eCCR. The oxygen on a Choptima is not something you’ll ever be unable to reach and turn off. It’s also easy to add in-line later.

My Choptima instructor recommended we remove the O2 inline shutoff. It doesn't seem to add anything useful, and if you screw up and leave the shutoff closed, it's between you and the RB (read: almost but not quite impossible to reach).