NERD 2nd thoughts...

[kammel78]

So, I bought a NERD a while back to use as my primary display for my Sidewinder and so far I've really enjoyed being able to see my computer at all times. I run my 'winder completely manual, no ADV, so oftentimes both hands are busy and even though it only takes a sec, it's still nice to have the display always in my sight.

Anyway, because of my teaching I do a good bit of oc diving while all of my cc diving is just fun diving. Usually, they don't really crossover, schedule-wise, but during my last class I wanted to get a dive in on my 'winder before heading back home. The dive would've been early morning the day after class ended, but what occurred to me was that my NERD wouldn't have any of my tissue loading from the previous 4 days of diving, and therefore my deco on the NERD would be off. My main oc computer is a Teric and while it would have all my tissue loading, it wouldn't accurately track my pO2 on a cc dive since I run my pO2 manually.

Now I'm wondering if I'd be better of getting a Petrel 2 that I can use as primary on my 'winder and carry as a backup when I'm on oc. What do you guys think, am I overthinking or missing anything?

 

[tbone1004]

if you really like the NERD you can helmet mount it when diving OC like Brian Kakuk does which is a great option. The other one is that if you compare the deco schedules and tissue loadings between your Teric and your NERD, you shouldn't find that much of a discrepancy if you have a relatively stable ppO2 while running it manually. If you don't have deco times off by more than a couple of minutes at the end of the dive, it's certainly "close enough". Remember that with deco we measure with a micrometer, mark with chalk, and cut with an axe.

 

[kammel78]

if you really like the NERD you can helmet mount it when diving OC like Brian Kakuk does which is a great option. The other one is that if you compare the deco schedules and tissue loadings between your Teric and your NERD, you shouldn't find that much of a discrepancy if you have a relatively stable ppO2 while running it manually. If you don't have deco times off by more than a couple of minutes at the end of the dive, it's certainly "close enough". Remember that with deco we measure with a micrometer, mark with chalk, and cut with an axe.

Hmm, I haven't seen Brian's helmet mount. What does he do with the cable, just wrap it up? Then, I'd also have to get a helmet

That's a good point about comparing the deco schedules, I just need to set my Teric's setpoints to what I normally run on the 'winder. I appreciate the fact that just about all deco dives are experimental in practicality, I just like to err on the side of caution especially being fairly new-ish to cc.

 

[grantctobin]

Hmm, I haven't seen Brian's helmet mount. What does he do with the cable, just wrap it up? Then, I'd also have to get a helmet

That's a good point about comparing the deco schedules, I just need to set my Teric's setpoints to what I normally run on the 'winder. I appreciate the fact that just about all deco dives are experimental in practicality, I just like to err on the side of caution especially being fairly new-ish to cc.

What have you been running your Teric setpoint to when using it as a backup if not your intended/avg ccr setpoint?

 

[tbone1004]

Hmm, I haven't seen Brian's helmet mount. What does he do with the cable, just wrap it up? Then, I'd also have to get a helmet

That's a good point about comparing the deco schedules, I just need to set my Teric's setpoints to what I normally run on the 'winder. I appreciate the fact that just about all deco dives are experimental in practicality, I just like to err on the side of caution especially being fairly new-ish to cc.

his is an OG nerd so the box is mounted to the back of his helmet. With a nerd2 I'd probably put a bolt snap on the end of the cable and clip it to a tight bungee loop on the back of the helmet
NERD2 question.

 

[kammel78]

his is an OG nerd so the box is mounted to the back of his helmet. With a nerd2 I'd probably put a bolt snap on the end of the cable and clip it to a tight bungee loop on the back of the helmet
NERD2 question.

Awesome, thanks for the link!

 

[kammel78]

What have you been running your Teric setpoint to when using it as a backup if not your intended/avg ccr setpoint?

Much more conservative than what I'm actually running. Learning the mccr I wasn't super confident in my ability to maintain a tight pO2, so I'd run the backup conservatively and worst case scenario, primary dies and I end up with extra deco. With more experience and confidence, I have a better idea of the pO2 range I can manage on a real dive and set my backup accordingly.

 

[rjack321]

ppO2 doesn't matter that much honestly. Especially on the sidewinder the small CL and minimal mixing means my ppO2 swings around wildly whenever I inject. The deco on my predator ext compared to the deco on my fixed ppO2 petrel is never off by more than a couple minutes.

 

[doctormike]

So, I bought a NERD a while back to use as my primary display for my Sidewinder and so far I've really enjoyed being able to see my computer at all times. I run my 'winder completely manual, no ADV, so oftentimes both hands are busy and even though it only takes a sec, it's still nice to have the display always in my sight.

Anyway, because of my teaching I do a good bit of oc diving while all of my cc diving is just fun diving. Usually, they don't really crossover, schedule-wise, but during my last class I wanted to get a dive in on my 'winder before heading back home. The dive would've been early morning the day after class ended, but what occurred to me was that my NERD wouldn't have any of my tissue loading from the previous 4 days of diving, and therefore my deco on the NERD would be off. My main oc computer is a Teric and while it would have all my tissue loading, it wouldn't accurately track my pO2 on a cc dive since I run my pO2 manually.

Now I'm wondering if I'd be better of getting a Petrel 2 that I can use as primary on my 'winder and carry as a backup when I'm on oc. What do you guys think, am I overthinking or missing anything?

Assuming that this is a DIveCAN NERD with a wet pluggable cable, right?

If you have an adequate DC for OC and you weren't planning on adding a backup for your OC diving, why not just stick the NERD in your pocket when you dive OC, and not worry about rigging up a helmet mount? Then it will have accurate deco information when you switch back to CCR. And if your Teric failed and you wanted a backup, you could just pull the NERD out of your pocket. You certainly don't need that sort of continual information feed for OC diving.

 

[rjack321]

Do you really have residual N2 on the CCR Nerd when you get back in the water on OC? Seems like short surface intervals or a mix of CCR and OC dives on the same day?