Breathing rate affects NDL

[Diogao13]

Hi,

Does the personal breathing rate directly related to the tank pressure affects the NDL calculation time when using transmitters?

For example in a shallow dive around 5m but with a tank pressure around 80bar, will the computer reduce the NDL to match it with the security value around 50bar?

Thank you

 

[Still Kicking]

No. The computer most likely calculates the gas time remaining (based on
SAC, pressure, tank capacity etc.) but that is different from the NDL.

 

[inquis]

Some computers do take the lesser of the Gas Time Remaining and NDL. The Scubapro Luna (maybe other models, as well) calls that "Remaining Bottom Time". Shearwater computers give you NDL and GTR, and you make the call.

 

[BoltSnap]

The "clock" for NDL is based on decompression status when the "clock" for gas consumption/remaining pressure is based on gas consumption rate/pressure remaining. They are not related to each other.

 

[happy-diver]

Look Ma!

No batteries!

 

[dmaziuk]

Hi,

Does the personal breathing rate directly related to the tank pressure affects the NDL calculation time when using transmitters?

For example in a shallow dive around 5m but with a tank pressure around 80bar, will the computer reduce the NDL to match it with the security value around 50bar?

ScubaPro's "Human Factor" ones may, but they'll be going by your breathing/heart rate rather than remaining gas. (Whether their "Human Factor" is appreciably different from snake oil is a different question.)

 

[scubadada]

ScubaPro's "Human Factor" ones may, but they'll be going by your breathing/heart rate rather than remaining gas. (Whether their "Human Factor" is appreciably different from snake oil is a different question.)

...and skin temperature

 

[boulderjohn]

In case it wasn't clear above, the rate at which you breathe does not affect your NDL.

The rate at which you breathe does affect the calculation for how long it will take to use up the remaining air.

 

[admikar]

Look Ma!

View attachment 850586

No batteries!

View attachment 850587

I'm ashamed to admit that my SPG looked like that after an "easy" dive where my budy run out of gas and we were in deco. I was afraid to test how many breaths I had remaining after surfacing.

 

[dmaziuk]

In case it wasn't clear above, the rate at which you breathe does not affect your NDL.

The rate at which you breathe does affect the calculation for how long it will take to use up the remaining air.

Heart rate and breathing rate are linked to work, harder work is linked to faster on/off-gassing. I've no idea how SP's "ADT" algorithm works but if it were me programming it: working at the bottom => faster on-gassing => hitting M0 values faster than you otherwise would. I.e. shorter NDL. Working at the safety stop => faster off-gassing => lower surfacing GF.

That's ScubaPro "Human factors". The regular AI computer with GTR will only do what you say: calculate how many breaths you have let in your tank ass-u-me-ing your breathing rate isn't going to change.