Does Venturi and breathing adjustment all the way on during a dive have any impact on the bottom time ?

[WOB0.01J]

Hello Divers.

Yesterday I dove at nubble lighthouse in Maine, NH. Great dive with very little current. However, my air usage went up a lot during that dive. I hit 45 feet max depth with a dive time of 35 mins. Start off pressure was 3050 PSI. Surfaced with 800 PSI. Compare this dive to last week, basically same depth and time but surfaced with more than 1300 psi. (Both dive with really good buoyancy control and breathing control) The only difference that I can recall between those two dives were my reg venturi was on the whole time yesterday, but the venturi was turned off for 10 mins or so on the last week dive. Does venturi and breathing adjustment have that big of an impact on air usage? I do like my venturi and breathing adjustment all the way out which makes it as easy as possible to get air : )

Thanks

 

[Gone for diving]

I doubt it,
But it is possible you are taking larger breath....

I think it's more how relaxed you where compared to last time...
Tends to be more of a mind thing,
unless you are doing hard work, like kicking more for some reason...

 

[WOB0.01J]

I doubt it,
But it is possible you are taking larger breath....

I think it's more how relaxed you where compared to last time...
Tends to be more of a mind thing,
unless you are doing hard work, like kicking more for some reason...

The current was stronger during yesterday's dive compare to last week. And i for sure was kicking a little bit more. Maybe that explains it a little

 

[scrane]

It might affect inexperienced divers, but I think experienced divers have firmly established their breathing patterns.

 

[scrane]

Double post.

 

[SlugLife]

@Rol diy covered much of what I was going to say.

Every time I burn through air faster, it's usually one of:

* I'm not monitoring breathing rate at all.
* I start a dive out-of-breath, such as after a swim to the dive-spot.
* Exceeding my typical slow finning-rate
* Allowing myself to get a little "out of breath" and then letting that continue throughout the dive.

I'd suggest:

* Pay close attention to your breathing rate.
* Any time your breathing rate goes up even a little, greatly reduce exertion.

 

[Gone for diving]

A tip you may already now, but for playing in currents. If you plaster your self against the bottom the current is not nearly as strong. Depending on what you are trying to do...
even just 5ft off the bottom the current tends to be stronger than just skimming bottom....

 

[Gone for diving]

Think, sleepy really works for me,

 

[WOB0.01J]

* I'm not monitoring breathing rate at all.
* I start a dive out-of-breath, such as after a swim to the dive-spot.
* Exceeding my typical slow finning-rate
* Allowing myself to get a little "out of breath" and then letting that continue throughout the dive.

Awesome break down of the issue. I wasn't CLOSELY monitoring breathing rate. Finning hard plus out of breath might be the issue here. I guess it has very little to do with the reg setting

 

[admikar]

TBH, I don't recall if I have ever seen any tests on WOB with venturi on or off, but IIRC, venturi's sole purpose is air flow to prevent or at least mitigate free flow