Dive computer sensitivity

This was sort of prompted by another thread on the cause of a violation.

I dive an Oceanic Veo 2.0, wrist mounted, on which I now have 16 dives. This is my first dive computer.

I have yet to log a dive that did not give me an ascent rate violation, regardless of my ascent rate profile. I have come to the conclusion, after some experimentation, that this is resulting from hand movement.

As a new diver still learning, I am aware that I move my hands too much. I'm working on it. Nonetheless, I also use my right hand to equalize, and this will continue. In the other thread, it was suggested that this movement could be slowed down. I don't view this as a practical suggestion, as I feel that I have other (more important) things to worry about rather than if the computer doesn't like how fast I move my hand.

So to the question, then, is this level of sensitivity common across computers?

gcarter:

I have yet to log a dive that did not give me an ascent rate violation, regardless of my ascent rate profile. I have come to the conclusion, after some experimentation, that this is resulting from hand movement.

As a new diver still learning, I am aware that I move my hands too much. I'm working on it. Nonetheless, I also use my right hand to equalize, and this will continue. In the other thread, it was suggested that this movement could be slowed down. I don't view this as a practical suggestion, as I feel that I have other (more important) things to worry about rather than if the computer doesn't like how fast I move my hand.

Click to expand...

I'm a little confused. Just to clarify, you only observe ascent rate violations during descent, right? Because that's when it would be necessary to pinch your nose to equalize your ears. Most people don't have to equalize their ears during ascent, you know.

gcarter:

So to the question, then, is this level of sensitivity common across computers?

Click to expand...

No. However, most computers on the market nowadays have a programmed ascent rate threshold, above which a "violation" is reported. This threshold can be a fixed number or one that varies with depth.

Have you considered using your left hand to pinch your nose during equalization while using your right hand to operate the power inflater (crossed hands setup)?
Or, have you thought about using an alternative method of ear clearing that doesn't require a nose-pinch?
Another option is to mount the computer in a console and clip the console off to a chest D-ring. In this way, the computer doesn't move relative to your body and you can always see the display by glancing down.

Are you descending in an out-of-control fashion? By that, I mean can you arrest your descent immediately at any point in the water column?
I've found that, during initial descent, novice divers have a tendency to dump all the air from their BCD at the surface, then struggle to equalize their ears as they plummet like a rock. They rely on kicking to maintain depth, which turns diving into a stressful event. Managing a descent should be a calm, effortless endeavor. Under the majority of conditions, there is no pressing need to descend quickly. If that's the case, then why hurry? Take your time. Let out only enough gas from your BCD in order to get neutrally buoyant. In fact, it helps to constantly aim for being neutrally buoyant throughout the descent (as well as other phases of the dive). Given a starting point of neutral buoyancy, a normal exhalation should allow you to descend easily. Hit the power inflater button as needed -- usually small but frequent bursts during initial descent.

There are other benefits to descending slowly: easier to maintain contact with buddy, easier to help out buddy if needed, more time to react to problems/issues in the environment, less likely to crash into the bottom, more time to equalize, etc.

I found the same thing with my older Oceanic computers, also wrist mounted. As long as you know the cause is arm movement and not that you are ascending too quickly, just ignore it. You can easily monitor and control your ascent rate without that particular graphic feedback. Thankfully, the Oceanic computers do not penalize you for perceived ascent rate violations.

Hi,
the Veo 2.0 has 2 levels of ascent rate "sensitivity"; when shallower than 60ft its max ascent rate (segment 5) is 30fpm ... that's on paper.

In general, dive computers measure ascent rate by looking at the delta in absolute pressure, and closer you are to the surface and more iffy things are

Question: at which depths do you happen to notice ascent rate violations? Deep? Shallow? Everywhere?

Alberto (aka eDiver)

Bubbletrubble:

I'm a little confused. Just to clarify, you only observe ascent rate violations during descent, right? Because that's when it would be necessary to pinch your nose to equalize your ears. Most people don't have to equalize their ears during ascent, you know.

Click to expand...

No, I have seen it while ascending, descending, and while stable - all from just arm movement.

Bubbletrubble:

No. However, most computers on the market nowadays have a programmed ascent rate threshold, above which a "violation" is reported. This threshold can be a fixed number or one that varies with depth.

Have you considered using your left hand to pinch your nose during equalization while using your right hand to operate the power inflater (crossed hands setup)?
Or, have you thought about using an alternative method of ear clearing that doesn't require a nose-pinch?
Another option is to mount the computer in a console and clip the console off to a chest D-ring. In this way, the computer doesn't move relative to your body and you can always see the display by glancing down.

Click to expand...

I have tried other methods, and the only one that works reliably for me at this point, it may change over time, is the nose pinch. I bought a wrist mount on purpose, for three reasons: I wanted the redundancy with the mechanical guages, the wrist mount is quicker / easier to look at with minimum distraction, and I can more comfortably manage my inflator with my left while watching my depth with my right. YMMV.

Bubbletrubble:

Are you descending in an out-of-control fashion? By that, I mean can you arrest your descent immediately at any point in the water column?
I've found that, during initial descent, novice divers have a tendency to dump all the air from their BCD at the surface, then struggle to equalize their ears as they plummet like a rock. They rely on kicking to maintain depth, which turns diving into a stressful event. Managing a descent should be a calm, effortless endeavor. Under the majority of conditions, there is no pressing need to descend quickly. If that's the case, then why hurry? Take your time. Let out only enough gas from your BCD in order to get neutrally buoyant. In fact, it helps to constantly aim for being neutrally buoyant throughout the descent (as well as other phases of the dive). Given a starting point of neutral buoyancy, a normal exhalation should allow you to descend easily. Hit the power inflater button as needed -- usually small but frequent bursts during initial descent.

There are other benefits to descending slowly: easier to maintain contact with buddy, easier to help out buddy if needed, more time to react to problems/issues in the environment, less likely to crash into the bottom, more time to equalize, etc.

Click to expand...

Again, the issue is not ascent or descent rate - it is arm movement. I have concluded that I need to accept this as being a behaviour of my particular computer - I am not looking for a solution. I am just curious as to how common this level of sensitivity is.

DiveNav:

Hi,
the Veo 2.0 has 2 levels of ascent rate "sensitivity"; when shallower than 60ft its max ascent rate (segment 5) is 30fpm ... that's on paper.

In general, dive computers measure ascent rate by looking at the delta in absolute pressure, and closer you are to the surface and more iffy things are

Question: at which depths do you happen to notice ascent rate violations? Deep? Shallow? Everywhere?

Alberto (aka eDiver)

Click to expand...

My max depth to date is 18.9M. I have noticed it at all depths within that range, which is all based on that max rate.

gcarter:

No, I have seen it while ascending, descending, and while stable - all from just arm movement.

Click to expand...

Your computer isn't the problem. Stop flailing your right arm around so much.

If the ascent rate violations are occurring while ascending and while being "stable," then it couldn't possibly be caused by arm movement related to nose-pinch ear equalization. The vast majority of divers do not have to equalize their ears under those circumstances.

The only other legitimate cause of an ascent rate violation artifact is moving your right wrist too quickly to view the display. Move it smoothly/deliberately and your problem will disappear.

Bubbletrubble:

Your computer isn't the problem. Stop flailing your right arm around so much.

If the ascent rate violations are occurring while ascending and while being "stable," then it couldn't possibly be caused by arm movement related to nose-pinch ear equalization. The vast majority of divers do not have to equalize their ears under those circumstances.

The only other legitimate cause of an ascent rate violation artifact is moving your right wrist too quickly to view the display. Move it smoothly/deliberately and your problem will disappear.

Click to expand...

I am not sure why you are focussing on the equalization. I just mentioned that as one of the reasons why I move my arms, why the computer gets moved. And I know I am moving my arms too much in general, I stated that in the original post.

I am not trying to solve a problem here, really. If the issue disappears when my arm movements settle down as my skills improve, great. Until then I am ignoring the violation - which does not mean I am ignoring my actual ascent rate, which is fine.

I really was just wondering if this level of sensitivity was common or not, that's all.

Fair enough. I kept mentioning the equalization issue because, short of responding to some sort of emergency, I can't think of any other reason to purposefully move that arm in a rapid fashion. Newer divers tend to be twitchy and wave their arms wildly about to maintain buoyancy, move through the water, change orientation, or feel more "balanced" in the water. As you gain experience, these computer issues will subside.

FWIW, I'm fairly certain that if you had gone with a Suunto-branded wristmounted computer, you would still register ascent rate violation artifacts. That's just based on my experience with Suuntos.

Bubbletrubble:

Fair enough. I kept mentioning the equalization issue because, short of responding to some sort of emergency, I can't think of any other reason to purposefully move that arm in a rapid fashion. Newer divers tend to be twitchy and wave their arms wildly about to maintain buoyancy, move through the water, change orientation, or feel more "balanced" in the water. As you gain experience, these computer issues will subside.

Click to expand...

"Twitchy" is a good word LOL. I thought I had it under better control until my son and I went diving with the GoPro. What a rude awakening, no style points for me! Getting better, but still a ways to go.

Bubbletrubble:

FWIW, I'm fairly certain that if you had gone with a Suunto-branded wristmounted computer, you would still register ascent rate violation artifacts. That's just based on my experience with Suuntos.

Click to expand...